Characteristics of <i>BRCA1</i> / <i>2</i> mutations carriers including large genomic rearrangements in high risk breast cancer patients

다국어 초록 (Multilingual Abstract)

<P><B>Purpose</B></P><P>We investigated the prevalence of <I>BRCA1/2</I> small mutations and large genomic rearrangements in high risk breast cancer patients who attended a genetic counseling clinic.</P><P><B>Methods</B></P><P>In total 478 patients were assessed for <I>BRCA1/2</I> mutations by direct sequencing, of whom, 306 were identified as non-carriers of <I>BRCA1/2</I> mutation and assessed for large rearrangement mutations by multiplex ligation-dependent probe amplification. Family history and clinicopathological characteristics of patients were evaluated.</P><P><B>Results</B></P><P>Sixty-three mutation carriers (13.2%) were identified with <I>BRCA1</I> mutations (6.3%) and <I>BRCA2</I> mutations (6.9%), respectively. Mutation frequency was affected by familial and personal factors. Breast cancer patients with family history of breast and ovarian cancer showed the highest prevalence of <I>BRCA1/2</I> mutations (67%), and triple-negative breast cancer (TNBC) patients showed high <I>BRCA1</I> mutation prevalence (25%). The three probands of <I>BRCA1</I> deletion (1%) represented both familial risk and personal or clinicopathological risk factors as two with TNBC and one with bilateral ovarian cancer.</P><P><B>Discussion</B></P><P>This is the largest study assessing large genomic rearrangement prevalence in Korea and <I>BRCA1</I> deletion frequency was low as 1% in patients without <I>BRCA1/2</I> small mutations. For clinical utility of large genomic rearrangement testing needs further study.</P>