BRAF mutation in multiple primary cancer with colorectal cancer and stomach cancer

Aims: Recently, BRAF mutation testing has been introduced as a marker in differentiating Lynch syndrome from sporadic colorectal cancers or in predicting colorectal cancers with worse prognosis. Individuals with hereditary predisposition to cancer development are at an increased risk of developing multiple primary cancers. The purpose of this study is to identify mutation in the BRAF gene in multiple primary cancers with colorectal cancer and stomach cancer.

Methods: BRAF mutation was analysed in 45 patients with colorectal cancer and stomach cancer, synchronously or metachronously.

Results: Mean age was 64.07 years (range: 47-83 years). For the colorectal cancer, tumors were located at the sigmoid colon in eight patients (17.8%) and at the rectum in 22 patients (48.9%). Twenty-three patients (51.1%) had synchronous cancer. Four patients (8.9%) had family members with cancer. BRAF mutation was identified in three patients (6.7%). All three of these patients had metachronous cancers. The colorectal cancers were located in the sigmoid colon (1 patient) and the rectum (2 patients).

Conclusions: BRAF mutation rate was low in the multiple primary cancer with colorectal cancer and stomach cancer. With only BRAF gene study, it was not possible to identify any correlation with family history of colorectal cancer. Further study means considering other genes - MSI, MSH2, MLH1, MSH6.