Table 2.

Steps for the immunohistochemistry testing

(1) Do an immunohistochemistry 4-panel test for MLH1, MSH2, MSH6 and PMS2.

(2) If the MLH1 immunohistochemistry result is abnormal, use sequential BRAF

(3) V600E and MLH1 promoter hypermethylation testing to differentiate sporadic and Lynch syndrome-associated colorectal cancers. First do a BRAF V600E test.

(4) If the BRAF V600E test is negative, do an MLH1 promoter hypermethylation test.

(5) If the MLH1 promoter hypermethylation test is negative, confirm Lynch syndrome by genetic testing of germline DNA.

In term of steps 2–4, if the MSH2, MSH6 or PMS2 immunohistochemistry results are abnormal, confirm Lynch syndrome by subsequent genetic testing of germline DNA