Colorectal Cancer

Indications for Testing

Colorectal bleeding
Family history of colorectal cancer (CRC)
Clinical symptoms consistent with genetic/hereditary CRC (eg, MUTYH-associated polyposis (MAP), familial adenomatous polyposis (FAP), Turcot syndrome, Gardner syndrome)

Histology

All polyps removed should have histologic examination
Tissue is gold standard for tumor classification and further testing
- KRAS, NRAS, BRAF, PIK3CA, PTEN genes for prognostication and therapy decisions
  - PTEN by IHC is adequate testing
- Microsatellite instability (MSI)
- Mismatch repair (MMR) genes
Immunohistochemistry (IHC) – identifies MMR genes to guide MMR gene variant testing
- All tumors should be tested – ~15% of sporadic CRC will have MSI
- MLH1, MSH2, MSH6, PMS2 – MMR genes to test based on IHC results

Genetic Testing

MMR genes – should be considered for patients with newly diagnosed CRC
- Presence confirms Lynch syndrome
Gene testing for other more rare syndromes should be based on clinical presentation and family history, and in conjunction with genetic consultation (see NCCN guidelines – Genetic Familial High Risk Assessment: Colorectal, 2016; ACMG, 2015)

Prognosis

Anatomic location of tumor within colon appears to make a difference in overall survival as well as treatment response (Venook, 2016)
- Left-sided tumors have better prognosis than right-sided tumors
MMR-deficient tumors – generally more favorable prognosis
Chromosomal alterations in 8p, 17p, 18p – associated with poor prognosis
Serum markers
- Carcinoembryonic antigen (CEA) – measure prior to surgery (ASCO, 2006)
- Other potential but not validated serum markers – carbohydrate antigen (CA) 19-9, CA242, circulating tumor cells (CTC), and tissue inhibitor of metalloproteinase-1 (TIMP-1)
  - CTC – independent predictor of progression-free and overall survival

Gene testing to predict the effectiveness of therapies that target the EGFR pathway

Gene Testing to Predict the Effectiveness of Therapies that Target the EGFR Pathway
KRAS	Variants are associated with inhibited response to anti-EGFR therapy Most commonly in codons 12 and 13 of exon 2 Individuals who are candidates for anti-EGFR therapy should have testing for KRAS gene variants (ASCO, 2015; NCCN, 2015; ESMO, 2014)
BRAF	Variants are associated with inhibited response to anti-EGFR therapy Most variants are in codon 600 Recommended when no variants are found in KRAS gene (NCCN, 2015; ESMO, 2014)
NRAS	Variants are associated with relative resistance to anti-EGFR therapy (less common) Most commonly in codons 59 and 61 of exon 3, codons 117 and 146 of exon 4 Individuals who are candidates for anti-EGFR therapy should have testing for KRAS gene variants (ASCO, 2015; NCCN, 2015; ESMO, 2014)
PTEN	Variants in this gene may be associated with relative resistance to anti-EGFR therapy
PIK3CA	Exon 20 associated with relative resistance to anti-EGFR therapy (it is independent of RAS binding) Exon 9 gain of function variants may have no effect on anti-EGFR therapy (requires interaction with RAS)
ASCO = American Society of Clinical Oncology; NCCN = National Comprehensive Cancer Network; ESMO = European Society for Medical Oncology

Differential Diagnosis

Diverticulitis
Inflammatory bowel disease
- Crohn disease
- Ulcerative colitis
Irritable bowel syndrome
Hemorrhoids/fissures

Direct evidence from clinical trials concludes that fecal occult blood testing and flexible sigmoidoscopy reduces mortality from colorectal cancer (CRC); however, National Comprehensive Cancer Network recommends colonoscopy as the preferred screening method (NCCN, 2015)
Fecal occult blood testing
- 50% of confirmed colon cancer cases have a negative fecal occult blood test (FOBT)
  - If patient is at risk, consider sigmoidoscopy or colonoscopy even in the presence of a negative FOBT
- Positive FOBT mandates further evaluation (eg, colonoscopy)
Flexible sigmoidoscopy/colonoscopy – negative result does not rule out CRC
- 90% sensitivity for lesions ≥10 mm
Septin 9
- Biomarker for presence of CRC – high negative predictive values
- Indicated for individuals ≥50 years who have an average risk and no family history of CRC
- Not recommended for individuals with
  - History of previous CRC
  - Above-average risk (eg, family history of early onset CRC, hereditary CRC)
  - Previous polyp removal
- Not intended as substitute for colonoscopy – may be useful as a complement to colonoscopy or for those who are unwilling or unable to have a colonoscopy (Choosing Wisely: 15 Things Physicians and Patients Should Question, American Society of Clinical Pathology, 2016)
  - Patients with elevated level should undergo colonoscopy to rule out CRC
- Has been shown to detect cancers in cecum, ascending colon, transverse colon, splenic flexure, descending colon, sigmoid, recto-sigmoid junction, and rectum
Multi-targeted stool-based DNA testing
- Emerging screening strategy that combines a fecal immunochemical test (FIT) with testing for altered DNA biomarkers in cells shed into the stool
- Multi-targeted stool DNA testing has increased single-test sensitivity for detecting CRC compared with FIT alone
- Reasonable alternative to other stool-based and visualization-based tests (USPSTF, 2016)

Colorectal screening for persons with average risk (beginning at 50 years)

Colorectal Screening for Persons with Average Risk* (beginning at 50 years)
Organization	Recommendation
USPSTF, 2016	50-75 yrs – CRC screening recommended; no specific screening test is recommended (screening tests vary according to risks and benefits) 76-85 yrs – consider screening for certain individuals who are healthy enough for colonoscopy, and lack comorbidity that would limit life expectancy Adults in this age group who have never been screened for CRC are more likely to benefit >85 yrs – CRC screening not recommended
AAFP, 2010	50-75 yrs – one of the following screening regimens** Annual screen for colorectal cancer (CRC) using FOBT Sigmoidoscopy every 5 yrs combined with high-sensitivity FOBT every 3 yrs Colonoscopy every 10 yrs 76-85 yrs – recommend against routine screening for CRC; however, there may be considerations that support CRC screening in an individual patient >85 yrs – CRC screening not recommended
ACS, 2013	One of the following regimens** Flexible sigmoidoscopy every 5 yrs Colonoscopy every 10 yrs Double-contrast barium enema every 5 yrs CT colonography every 5 yrs No upper age limit for screening
Average risk – age ≥50 yrs; no history of adenoma or inflammatory bowel disease (IBD); negative family history (not having one first-degree or two second-degree relatives with CRC, or a clustering of Lynch syndrome-related cancers in the family) *Patients with a family member diagnosed with colon cancer <60 yrs should begin colonoscopy screenings every 5-10 yrs starting at age 40 or 10 yrs before the age of the youngest family member diagnosed USPSTF = U.S. Preventive Services Task Force; AAFP = American Academy of Family Practice, ACS = American Cancer Society

Serum carcinoembryonic antigen (CEA)
- Elevated postoperative titer predicts tumor recurrence
- Preoperative and postoperative monitoring for changes in concentration
  - Stage II or III tumors – measure every 3 months post operation, continuing for 3 years
- Patient with metastatic disease – monitoring may help evaluate treatment response
Serum circulating tumor cell count (CTC) – in metastatic tumors, monitor disease progression and response to therapy
Others
- Serum CA 19-9
- Deletion 18q – not enough data to recommend use
- 9q22.2-31.2 – promising new marker for hereditary colorectal cancers

UGT1A1 genotyping
- Uridine diphosphate glucuronosyl transferase (UGT1A1) is responsible for clearance of irinotecan, a camptothecin analogue used in treatment of advanced colon cancer
- Decreased gene expression may lead to drug toxicity (development of severe neutropenia)
  - Two gene variants responsible for 98-99% of genotypes in the Caucasian population – *1 and *28 (repeat TA sequence)
- Routine reduction of dose in *28 homozygous is not recommended (Evaluation of Genomic Applications in Practice Working Group, 2014), but may identify patients at risk for adverse events and in need of closer monitoring
  - Selective genotyping based on patient preferences and predicted dosing
    - Higher doses associated with increased risk for certain genotypes that may not occur with lower dosing
    - Patients homozygous for *1 may tolerate aggressive treatment better than patients with the *28 variant
    - Patients homozygous for *28 may require a dose reduction to minimize dose-related adverse events
5-fluorouracil (5-FU) sensitivity – genotyping of DYPD and TYMS
- 5-FU is a fluoropyrimidine drug used in the treatment of colorectal cancer and other solid tumors
- Pharmacogenetic variations in genes such as DPYD and TYMS may contribute to risk of toxicity or altered therapeutic benefits
  - DPYD variant or TYMS variant detected – most variants or mutations are associated with increased risk for 5-FU toxicity
    - Alternative chemotherapeutic agents, therapeutic drug monitoring, altered 5-FU doses, or increased surveillance for adverse drug reactions may be indicated

Colorectal cancer (CRC) is the third most common form of cancer in the U.S. It can be roughly divided into sporadic and hereditary types.

Epidemiology

Incidence – 43.7/100,000 (2012 U.S. SEER data)
- Sporadic – most common form (~80%)
- Hereditary CRCs
  - Hereditary nonpolyposis colorectal cancer (HNPCC), or Lynch syndrome – accounts for 2-4% of CRC cases in the U.S. (NCCN, 2015)
  - Familial adenomatous polyposis (FAP) – occurs in 1/10,000 live births
    - ~0.5% of total CRC cases
  - MUTYH (formerly MYH)-associated polyposis (MAP) – ~1% of Caucasians are predicted to carry an MUTYH gene variant
  - Other inherited syndromes
    - Peutz-Jeghers syndrome (PJS) – 1/200,000
    - Juvenile polyposis syndrome (JPS) – 1/100,000
    - Hereditary diffuse gastric cancer – rare
    - Serrated polyposis syndrome – uncommon
    - Cowden syndrome (multiple hamartoma syndrome)
    - Li Fraumeni syndrome – rare
Age
- Sporadic – median is 70 years
- Hereditary – usually <60 years
Sex – M>F

Genetics

Sporadic
- TP53 gene – mutated in ~75% of sporadic tumors
- DCC gene – mutated in ~70% of CRCs
- DNA mismatch repair (MMR) genes – variant or modification found in 15% of sporadic tumor
Hereditary (NCCN, 2016)
- >10-15% of all CRC associated with familial clustering
- Lynch syndrome (hereditary nonpolyposis colorectal cancer)
  Associated with microsatellite instability (MSI) and MMR gene variant/modification – usually MLH1, MSH2, MSH6, PMS2
  
  Other genes (MLH3, PMS1, EPCAM, and EXO1) have been found
- FAP
  APC gene variants
  Autosomal dominant inheritance
  
  25% of cases are de novo
  
  Syndromes
  Classic FAP and attenuated FAP forms
  
  Gardner syndrome
  
  Turcot syndrome
- MAP
  MUTYH gene variants
  Autosomal recessive inheritance
  
  Two MUTYH variants, Y165C and G382D, account for 85% of MAP in Caucasians
  
  Biallelic variants appear to create risk for cancer
- PJS
  STK11 gene variants
  
  Autosomal dominant inheritance
  
  50% of patients do not have this variant
- JPS
  SMAD4 or BMPR1A gene variants
  
  Autosomal dominant inheritance
- Li Fraumeni syndrome – TP53 variant
- Cowden syndrome (PTEN hamartoma tumor syndrome)
  PTEN gene variants
  
  Autosomal dominant with high penetrance

Risk Factors

Diet high in animal fats (Western diet)
Patients with metabolic syndrome
Inflammatory bowel disease (eg, Crohn disease, ulcerative colitis)
Adenoma/sessile serrated polyp (SSP)
First-degree relative with colorectal adenoma or invasive CRC
Ureterosigmoidostomy – carcinoma can develop ≥15 years post procedure

Pathophysiology

Most CRCs arise from adenomatous polyps
- Villous adenomas transform into adenocarcinomas more frequently than tubular adenomas
- Subset of adenocarcinomas develop from hyperplastic-appearing polyps, especially large, right-sided polyps
- Adenocarcinoma arising in a polyp is considered malignant when it penetrates into the submucosa
Other less-common tumors can occur (lymphomas, endocrine, mesenchymal)

Clinical Presentation

Symptoms vary with tumor location – most are located in sigmoid colon and rectum
- Cecum and ascending colon – tumors may be very large without causing obstruction
  - Anemia – a common presenting symptom
- Descending and transverse colon – tumors tend to obstruct and cause annular lesions (apple core or napkin ring) with abdominal pain and bloating
- Rectosigmoid – hematochezia, tenesmus, and narrowing of stool caliber
Sporadic tumors – usually single tumors
Inherited syndromes (NCCN, 2016)
- Lynch syndrome
  May have multiple tumors
  
  Median age of 40-60 years (10 years younger than sporadic colorectal carcinoma)
  
  For more information, see Lynch syndrome and Lynch syndrome testing algorithm
- FAP
  FAP (classic)
  Affected persons develop hundreds to thousands of colon polyps and subsequent CRC
  Often present with multiple tumors
  
  Presence of ≥100 polyps is sufficient for clinical diagnosis (or <100 polyps at younger ages in a family with identified FAP)
  
  Median age of onset is 39 years
  
  Increased risk for other malignancy – thyroid (papillary cribiform-morular variant), medulloblastoma, hepatoblastoma, pancreas, gastric/duodenal
  
  Possible associated findings
  Osteomas – Gardner syndrome
  
  Gastric and duodenal polyps
  
  Dental anomalies
  
  Congenital hypertrophy of the retinal pigment epithelium (CHRPE)
  
  CNS tumors – Turcot syndrome
  
  FAP (attenuated)
  10-100 polyps (average is 30) – frequently right-sided distribution
  
  Cancer appears at older age than classic FAP (mean age >50 years)
  
  Risk of other malignancy similar to classic FAP
  
  Extraintestinal manifestations of classic FAP are rare
- MAP
  100-1,000 polyps (usually <100 polyps)
  
  Median age of onset is 45-59 years
  
  Often indistinguishable from attenuated FAP – may have similar extraintestinal manifestations or serrated polyp syndrome (may have serrated polyps)
  
  Increased risk for malignancy – duodenal cancer
- PJS
  Hamartomatous gastrointestinal polyps – tend to be fewer than FAP
  
  Perioral melanin pigmentation which tend to fade when adulthood reached
  
  Increased risk for other malignancy (breast, ovary, pancreas and gallbladder)
- JPS
  Juvenile hamartomatous polyps found mainly in colon
  
  Usually diagnosed in adolescence
  
  Median age for cancer is 33 years
- Serrated polyposis syndrome
  Serrated polyps usually >10 mm
  
  Risk for CRC not as high as other syndromes
- Li Fraumeni syndrome
  Lifetime risk of CRC increased
  
  Core tumors are sarcoma, breast, adrenocortical, and brain tumors
- Cowden syndrome
  Polyps often >50 with various histologies (eg, hyperplastic, adenomatous, hamartomatous)
  
  Risk much lower for CRC than FAP or MAP
  
  Increased risk for other malignancy (eg, skin, breast, thyroid, endometrial, brain)

Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

Mismatch Repair by Immunohistochemistry 0049302
Method: Qualitative Immunohistochemistry

Recommended Use

First-line screening test for Lynch syndrome (LS)

Highly recommended prior to ordering MMR germline variant analysis; results guide subsequent genetic testing

Determines MMR protein expression (MLH1, MSH2, PMS2, and MSH6) in tumor tissue

Refer to Additional Technical Information document for further content

Clinical sensitivity – 90%

Limitations

~10% of individuals with LS will have IHC tests that show normal staining of the MMR proteins

Because the correlation of MSI with IHC is not 100%, direct testing of MSI by PCR may be helpful

Occult Blood, Fecal by Immunoassay 2007190
Method: Quantitative Immunoassay

Recommended Use

Screen for colorectal cancer (CRC)

Colonoscopy is the recommended test of choice for individuals >50 years

More sensitive than guaiac testing

Limitations

Less sensitive than colonoscopy

Microsatellite Instability (MSI), HNPCC/Lynch Syndrome, by PCR 0051740
Method: Polymerase Chain Reaction/Fragment Analysis

Recommended Use

First-line screening test for LS

Genes included – MLH1, MSH2, MSH6, and PMS2

Refer to Additional Technical Information document for further content

Clinical sensitivity – 90%

Analytic sensitivity/specificity – >99%

Limitations

15% of sporadic CRCs are also MSI-H

Preoperative chemoradiation of rectal cancer may complicate IHC interpretation and/or decrease tumor mass and make MSI testing difficult

Evaluation of pretreatment biopsies will avoid this limitation

Epi proColon 2013906
Method: Polymerase Chain Reaction

Recommended Use

The Epi proColon test is indicated to screen adults of either sex, ≥50 years, defined as average risk for CRC, who have been offered and have a history of not completing CRC screening

Tests that are available and recommended in the USPSTF 2008 CRC screening guidelines should be offered and declined prior to offering the Epi proColon test

Patients with a positive Epi proColon test result should be referred for diagnostic colonoscopy

The Epi proColon test results should be used in combination with physician's assessment and individual risk factors in guiding patient management

For more information, please refer to the Instructions for Use

Follow-up

The Epi proColon test results should be used in combination with physician's assessment and individual risk factors in guiding patient management

Patients with a positive Epi proColon test result should be referred for diagnostic colonoscopy

Colon Cancer Gene Panel, Somatic 2011616
Method: Mass Spectrometry

Recommended Use

Indicated for individuals with metastatic CRC to guide treatment with anti-EGFR monoclonal antibodies (eg, cetuximab and panitumumab)

More cost effective than ordering multiple single gene assays

Detect variants in

KRAS – codons 12, 13, 61 (MassARRAY also detects codon 146)
BRAF – codon 600
PIK3CA – codons 542, 545, and 1047
NRAS – codons 12, 13, and 61

Refer to Additional Technical Information document for further content

Clinical sensitivity

KRAS – activating variant found in ~40% of CRCs
BRAF – activating variant found in ~10% of CRCs
PIK3CA – oncogenic variant found 10-20% of CRCs
NRAS – oncogenic variant found in ~3% of CRCs

Analytical sensitivity/specificity – 100%

Limitations

Limit of detection – ~10% mutant alleles

Variants outside of codons tested will not be detected

KRAS Mutation Detection with Reflex to BRAF Codon 600 Mutation Detection 2001932
Method: Polymerase Chain Reaction/Pyrosequencing

Recommended Use

Determine eligibility for anti-EGFR (cetuximab and panitumumab) therapy in patients with metastatic colorectal cancer

Evaluate two important genes in the EGFR pathway

Detect variants in codons 12, 13, and 61

Refer to Additional Technical Information document for further content

Reflex pattern – if KRAS variant is not detected, BRAF codon 600 variant detection test will be performed

Clinical sensitivity – activating KRAS variants found in ~40% of CRCs

Analytical sensitivity/specificity – 99%

Limitations

Limit of detection – 10% mutant alleles

Oncogenic variants outside of codons tested will not be detected

A substantial portion of individuals with wild-type KRAS still fail to respond to anti-EGFR agents, implicating downstream variants

KRAS Mutation Detection 0040248
Method: Polymerase Chain Reaction/Pyrosequencing

Recommended Use

Detects activating KRAS variants (codons 12, 13, 61) associated with anti-EGFR therapy resistance

Single gene assay

Clinical sensitivity – activating KRAS variants found in ~40% of CRCs

Analytic sensitivity/ specificity – 100%

Limitations

Limit of detection – 10% mutant alleles

Oncogenic variants outside of codons tested will not be detected

A substantial portion of individuals with wild type KRAS still fail to respond to anti-EGFR agents, implicating downstream variants

BRAF Codon 600 Mutation Detection by Pyrosequencing 2002498
Method: Polymerase Chain Reaction/Pyrosequencing

Recommended Use

Detect activating BRAF mutations at codon 600, which can indicate resistance to anti-EGFR therapy in colorectal cancer

This test is also used within the Lynch syndrome reflex testing pathway (for colorectal cancer specimens only)

Single gene assay

Clinical sensitivity – activating BRAF found in ~10% of CRCs

Analytic sensitivity/specificity – 100%

Limitations

Limit of detection – 10% mutant alleles

Oncogenic variants outside of codon tested will not be detected

BRAF V600E Mutation Detection in Circulating Cell-Free DNA by Digital Droplet PCR 2013921
Method: Polymerase Chain Reaction

Recommended Use

Determine BRAF V600E mutation status in patients with solid tumors to select candidates for targeted therapy with kinase (BRAF and/or MEK) inhibitors

Monitor response to therapy and disease progression in patients carrying BRAF V600E mutation

NRAS Mutation Detection by Pyrosequencing 2003123
Method: Polymerase Chain Reaction/Pyrosequencing

Recommended Use

Predict response to anti-EGFR and MAPK pathway therapies in a variety of malignancies including CRCs

Detect activating NRAS variants (codons 12, 13, 61) associated with relative resistance to anti-EGFR therapy

Single gene assay

Clinical sensitivity – oncogenic NRAS variant found in ~3% of CRCs

Analytic sensitivity/specificity – 100%

Limitations

Limit of detection – 10% mutant alleles

Oncogenic variants outside of codons tested are not detected

Presence or absence of variants does not guarantee a positive response to anti-EGFR therapies

PTEN by Immunohistochemistry 2004115
Method: Immunohistochemistry

Recommended Use

Detect loss of PTEN expression in tumor tissue

Possibly associated with relative resistance to anti-EGFR therapy

Does not include interpretation

Clinical sensitivity/specificity – loss of expression found in up to 50% of CRCs

Stained and returned to client pathologist; consultation available if needed

PTEN with Interpretation by Immunohistochemistry 2007031
Method: Immunohistochemistry

Recommended Use

Detect loss of PTEN expression in tumor tissue

Possibly associated with relative resistance to anti-EGFR therapy

Stained and returned to client pathologist; includes interpretation

Clinical sensitivity/specificity – loss of expression found in up to 50% of CRCs

PIK3CA Mutation Detection 2004510
Method: Polymerase Chain Reaction/Pyrosequencing

Recommended Use

Predict response to anti-EGFR and AKT/mTOR pathway therapies in a variety of malignancies, including colorectal cancer

Detect activating PIK3CA variants in exons 9 (codon 542, 545) and 20 (codon 1047)

Single gene assay

Clinical sensitivity – oncogenic PIK3CA variant found in 10-20% of CRCs, mostly exons 9 (60-65%) or 20 (20-25%)

Analytic sensitivity/specificity – 100%

Limitations

Limit of detection – 10% mutant alleles

Oncogenic variants outside of codons tested will not be detected

Presence or absence of variants does not guarantee a response or lack of response to anti-EGFR therapy

Familial Mutation, Targeted Sequencing 2001961
Method: Polymerase Chain Reaction/Sequencing

Recommended Use

Useful when a pathogenic familial variant identifiable by sequencing is known

Consultation with a genetics counselor is advised

Familial Adenomatous Polyposis Panel: (APC) Sequencing and Deletion/Duplication, (MUTYH) 2 Mutations 2004915
Method: Polymerase Chain Reaction/Sequencing/Multiplex Ligation-dependent Probe Amplification

Recommended Use

Preferred diagnostic or predictive test for familial adenomatous polyposis (FAP) and MUTYH-associated adenomatous polyposis (MAP)

APC gene – up to 90% of pathogenic variants detected by sequencing; ~8-12% of pathogenic variants detected by deletion/duplication testing

MAP – Y165C and G382D represent 85% of pathogenic MUTYH gene variants in Northern European Caucasians

Refer to Additional Technical Information for further content

Clinical sensitivity

Classic FAP – ~95%
Attenuated FAP – <30%
MAP in Northern European Caucasians – ~85% (must detect 2 pathogenic variants for diagnosis)

Analytical sensitivity/specificity for both APC and MUTYH – 99%

Limitations

APC gene

Deep intronic or regulatory region variants will not be identified
Breakpoints of large deletions/duplications will not be determined

Only two pathogenic MUTYH gene variants will be tested – Y165C and G382D

Diagnostic errors can occur due to rare sequence variations

Negative result does not rule out FAP, APC-associated polyposis, or MAP due to the possibility of an undetectable variant in the specific gene(s) analyzed or a variant in another gene

Carcinoembryonic Antigen 0080080
Method: Quantitative Electrochemiluminescent Immunoassay

Recommended Use

Monitor tumor recurrence

Limitations

Not sensitive or specific enough for screening in the general population

MUTYH-Associated Polyposis (MUTYH) 2 Mutations 2004911
Method: Polymerase Chain Reaction/Sequencing

Recommended Use

Acceptable diagnostic or predictive test for MAP in Northern European Caucasians; 85% diagnostic sensitivity in this ethnicity

For non-Caucasians, refer to MUTYH gene sequencing testing

Analytical sensitivity/specificity – 98%

Limitations

Not detected – large deletions or duplications; deep intronic, regulatory region, or promoter pathogenic variants

Only two pathogenic MUTYH gene variants are tested – Y165C and G382D

Diagnostic errors can occur due to rare sequence variations

MUTYH gene variants of unknown significance may be detected

Circulating Tumor Cell Count 0093399
Method: Immunomagnetic Separation/Immunofluorescent Stain/Computer Assisted Analysis

Recommended Use

Use in metastatic tumors in conjunction with clinical data and imaging to monitor response to therapy and disease progression

Cutoffs vary by tumor cell type

Limitations

CTC test is not as accurate as imaging in assessing whether a patient has progressive disease

Doxorubicin therapy patients – allow at least 7 days following administration of dose before testing

Not detected – CTCs that do not express EpCAM; CTCs that express EpCAM but not cytokeratins 8, 18, and 19

Serial CTCs should be performed in the same laboratory

MUTYH-Associated Polyposis (MUTYH) 2 Mutations with Reflex to Sequencing 2006307
Method: Polymerase Chain Reaction/Sequencing

Recommended Use

Preferred diagnostic or predictive test for MAP in Caucasians

For non-Caucasians, order MUTYH gene sequencing

Reflex pattern – MUTYH sequencing will be performed if two pathogenic variants are not identified by targeted testing for Y165C and G382D

Gastrointestinal Hereditary Cancer Panel, Sequencing and Deletion/Duplication, 16 Genes 2013449
Method: Massively Parallel Sequencing/Exonic Oligonucleotide-based CGH Microarray/Sequencing/Multiplex Ligation-dependent Probe Amplification

Recommended Use

Preferred test for individuals with suspected Lynch syndrome or another hereditary GI cancer syndrome

Analysis of specific genes included in this panel may be available individually at ARUP

Genes included – APC, BMPR1A, CDH1, EPCAM, MLH1, MSH2, MSH6, MUTYH, PMS2, PTEN, SDHB, SDHC, SDHD, SMAD4, STK11, TP53

For more information, refer to Additional Technical Information document

Limitations

Diagnostic errors can occur due to rare sequence variations

Not determined or evaluated – Variants in genes not included on the panel; deep intronic and regulatory region variants; breakpoints for large deletions/duplications; sequence changes in EPCAM gene

Deletions/duplications may not be detected in exon 9 in BMPR1A gene; exon 1 in CDH1 and MSH2 genes; exon 8 in PMS2 gene; exons 4, 6, and 7 in STK11 gene

Individuals with hematological malignancy and/or a previous allogenic bone marrow transplant should not undergo molecular genetic testing on peripheral blood specimen; testing of cultured fibroblasts or buccal specimen is required for accurate interpretation of test results; not all predisposing genes are analyzed

Guidelines

Allegra CJ, Jessup M, Somerfield MR, Hamilton SR, Hammond EH, Hayes DF, McAllister PK, Morton RF, Schilsky RL. American Society of Clinical Oncology provisional clinical opinion: testing for KRAS gene mutations in patients with metastatic colorectal carcinoma to predict response to anti-epidermal growth factor receptor monoclonal antibody therapy. J Clin Oncol. 2009; 27(12): 2091-6. PubMed

Allegra CJ, Rumble B, Schilsky RL. Extended RAS Gene Mutation Testing in Metastatic Colorectal Carcinoma to Predict Response to Anti-Epidermal Growth Factor Receptor Monoclonal Antibody Therapy: American Society of Clinical Oncology Provisional Clinical Opinion Update 2015 Summary. J Oncol Pract. 2016; 12(2): 180-1. PubMed

American Cancer Society Guidelines for the Early Detection of Cancer. American Cancer Society. Atlanta, GA [Revised Jul 2016; Accessed: Dec 2016]

Choosing Wisely. An initiative of the ABIM Foundation. [Accessed: Jan 2017]

Duffy MJ, van Dalen A, Haglund C, Hansson L, Holinski-Feder E, Klapdor R, Lamerz R, Peltomaki P, Sturgeon C, Topolcan O. Tumour markers in colorectal cancer: European Group on Tumour Markers (EGTM) guidelines for clinical use. Eur J Cancer. 2007; 43(9): 1348-60. PubMed

Evaluation of Genomic Applications in Practice and Prevention (EGAPP) Working Group. Recommendations from the EGAPP Working Group: can UGT1A1 genotyping reduce morbidity and mortality in patients with metastatic colorectal cancer treated with irinotecan? Genet Med. 2009; 11(1): 15-20. PubMed

Hampel H, Bennett RL, Buchanan A, Pearlman R, Wiesner GL, Guideline Development Group, American College of Medical Genetics and Genomics Professional Practice and Guidelines Committee and National Society of Genetic Counselors Practice Guidelines Committee. A practice guideline from the American College of Medical Genetics and Genomics and the National Society of Genetic Counselors: referral indications for cancer predisposition assessment. Genet Med. 2015; 17(1): 70-87. PubMed

Lin JS, Piper MA, Perdue LA, Rutter CM, Webber EM, O'Connor E, Smith N, Whitlock EP. Screening for Colorectal Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force JAMA. 2016; 315(23): 2576-94. PubMed

Locker GY, Hamilton S, Harris J, Jessup JM, Kemeny N, Macdonald JS, Somerfield MR, Hayes DF, Bast RC, ASCO. ASCO 2006 update of recommendations for the use of tumor markers in gastrointestinal cancer. J Clin Oncol. 2006; 24(33): 5313-27. PubMed

NCCN Clinical Practice Guidelines in Oncology, Colon Cancer. National Comprehensive Cancer Network. Fort Washington, PA [Accessed: Nov 2015]

NCCN Clinical Practice Guidelines in Oncology, Colorectal Cancer Screening. National Comprehensive Cancer Network. Fort Washington, PA [Accessed: Nov 2015]

NCCN Clinical Practice Guidelines in Oncology, Genetic/Familial High-Risk Assessment: Colorectal. National Comprehensive Cancer Network. Fort Washington, PA [Accessed: Jan 2016]

NCCN Clinical Practice Guidelines in Oncology, Rectal Cancer. National Comprehensive Cancer Network. Fort Washington, PA [Accessed: Nov 2015]

Protocol for the Examination of Specimens from Patients with Primary Carcinoma of the Colon and Rectum. Based on AJCC/UICC TNM, 7th ed. Protocol web posting date: Jan 2016. College of American Pathologists (CAP). Northfield, IL [Revised Oct 2013; Accessed: Dec 2016]

Schmoll HJ, Van Cutsem E, Stein A, Valentini V, Glimelius B, Haustermans K, Nordlinger B, van de Velde CJ, Balmana J, Regula J, Nagtegaal ID, Beets-Tan RG, Arnold D, Ciardiello F, Hoff P, Kerr D, Köhne CH, Labianca R, Price T, Scheithauer W, Sobrero A, Tabernero J, Aderka D, Barroso S, Bodoky G, Douillard JY, Ghazaly E, Gallardo J, Garin A, Glynne-Jones R, Jordan K, Meshcheryakov A, Papamichail D, Pfeiffer P, Souglakos I, Turhal S, Cervantes A. ESMO Consensus Guidelines for management of patients with colon and rectal cancer. a personalized approach to clinical decision making. Ann Oncol. 2012; 23(10): 2479-516. PubMed

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General References

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References from the ARUP Institute for Clinical and Experimental Pathology®

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