Detection of BRCA1/2 mutations in breast cancer patients from Thailand and Pakistan.

To the Editor : Women carrying a highly penetrant mutation in the genes BRCA1 (breast cancer 1) or BRCA2 have a 60–85% lifetime risk of breast cancer and a 15–40% lifetime risk of ovarian cancer (1). In Asia, the contribution of BRCA1/2 to breast cancer and the ethnic distribution of the different type of mutations remain relatively unexplored. We performed BRCA1/2 mutation screening using high-resolution melting curve analysis followed by Sanger sequencing (2) in an unselected hospital-based series of 77 breast cancer Pakistani patients residing in the Balochistan province (age range, 30–70; median age of disease onset, 47) and 121 early-onset patients and 9 patients with family history of breast cancer originating from Thailand (age range, 17–62; median age of disease onset, 36). All tested cases were, to our knowledge, unrelated. In BRCA1, one known nonsense mutation and three novel truncating mutations were observed in one or the other population. In BRCA2, one missense mutation causing aberrant splicing of the gene (3) and three novel truncating mutations were identified (Table 1). None of these mutations were observed in healthy subjects of respective population (85 controls from Balochistan and 190 controls from Thailand, respectively).