Diagnosis
➤ There is insufficient evidence to recommend PTEN analysis [expression by
immunohistochemistry (IHC) or deletion by fluorescence in situ hybridization
(FISH)] in colorectal carcinoma tissue for patients who are being considered for
therapy selection outside of a clinical trial.
(NR-Ins-U-Ins)
➤ Metastatic or recurrent colorectal carcinoma tissues are the preferred
specimens for treatment predictive biomarker testing and should be used if
such specimens are available and adequate. In their absence, primary tumor
tissue is an acceptable alternative, and should be used.
(EC-Ina/Ins-B/H-L)
➤ Formalin fixed paraffin embedded tissue is an acceptable specimen for
molecular biomarker mutational testing in colorectal carcinoma. Use of other
specimens (e.g. cytology specimens) will require additional adequate validation,
as would any changes in tissue processing protocols.
(EC-Ina/Ins-B/H-L)
➤ Laboratories must use validated colorectal carcinoma molecular biomarker
testing methods with sufficient performance characteristics for the intended
clinical use. Colorectal carcinoma molecular biomarker testing validation should
follow accepted standards for clinical molecular diagnostics tests. (S-C/A-B-
H/I)
➤ Performance of molecular biomarker testing for colorectal carcinoma must be
validated in accordance with best laboratory practices. (S-C/A-B-H/I)
➤ Laboratories must validate the performance of IHC testing for colorectal
carcinoma molecular biomarkers (currently IHC testing for MLH1, MSH2, MSH6,
and PMS2) in accordance with best laboratory practices.
(S-C/A-B-H/I)
➤ Laboratories must provide clinically appropriate turnaround times and optimal
utilization of tissue specimens by using appropriate techniques (e.g. multiplexed
assays) for clinically relevant molecular and immunohistochemical biomarkers
of colorectal cancer. (EC-Ina/Ins-B/H-L)
➤ Molecular and IHC biomarker testing in colorectal carcinoma should be initiated
in a timely fashion based upon the clinical scenario and in accordance with
institutionally accepted practices. (EC-Ina/Ins-B/H-L)
Note: Test ordering can occur on a case-by-case basis or by policies established by the medical
staff.
➤ Laboratories should establish policies to ensure efficient allocation and
utilization of tissue for molecular testing, particularly in small specimens. (EC-
Ina/Ins-B/H-L)
➤ Members of the patient's medical team, including pathologists, may initiate
colorectal carcinoma molecular biomarker test orders in accordance with
institutionally accepted practices. (EC-Ina/Ins-B/H-L)
