About 5-10% of breast cancer and 10-15% of ovarian cancer are hereditarily related. The Breast Cancer Registry encountered many breakthroughs in the past 15 years. Genetic testing has been offered to >4700 high-risk patients over the past decade under a research program. Laboratory technology improved from deciphering DNA codes with a capacity of 600 base pairs per test, in classical Sanger sequencing, to 1 terabyte of data, in the latest next-generation sequencing and nanopore sequencing technology. The testing panel was extended from merely two genes (BRCA1 and BRCA2) to a more comprehensive detailed analysis of 93 genes, and ad hoc whole exome/genome surveillance. The mutation pickup rate increased from 10.7% (only BRCA1 and BRCA2 genes) to 14.7% (extended panel). Mutations were often identified in patients with multiple cancers (30%), triple-negative breast cancer (24%), bilateral breast cancers (21%) or male breast cancer (18%). We learned that family history is the major factor for those cancer-free high-risk subjects. The aggregated pathogenic mutation rate of the 6 Hereditary Breast and Ovarian Cancer HBOC genes (BRCA1, BRCA2, CDH1, PALB2, PTEN and TP53) increased from 4.6% to 17.8% with increases in young-onset breast cancer family members, and a further rise to 50% for those with young-onset breast cancer and ovarian cancer in their family. Currently, these important genetic services for hereditary breast and ovarian cancers in Hong Kong are funded together by the Hospital Authority (BRCA testing for ovarian cancer) and charity The Registry. HA supports the genetic counseling service and the partially support the subsequent cascade of surgical/medical management of individuals. Our charity-supported ( The Registry ) offers advanced genetic testing in a state-of-the-art laboratory, annual intensive breast screening health service and use of parp inhibitors of metastatic ovarian cancer patients.
