ESMO Asia Virtual Congress 2020

Abstract 243P

Background

Target sequencing of epithelial ovarian cancer (EOC) has been widely used in clinical to detect the status of BRCA1/2 and genes in homologous recombination repair (HRR) pathway.

Methods

In a prospective study, unselected 215 EOC patients underwent germline and somatic testing with a 25-gene panel, of which 147 patients received target sequencing of 508 genes in OseqT panel. The sensitivity to platinum-based chemotherapy, OS and PFS were explored in various mutation categories.

Results

In 215 patients. 57 (26.51%) patients carried BRCA1 (46, 21.4%) or BRCA2 (14, 6.5%) pathogenic or likely pathogenic variants,3 of them carried both BRCA1 and BRCA2 variants. BRCA1/2 pathogenic carriers had significantly superior PFS and OS than non-mutated group. Deleterious mutation in HRR and MMR related genes can be found in 70 (32.6%) and 3 (1.4%) patients. Among 147 patients using OseqT panel for sequencing, 103 (70.1%), 15 (10.2%), 8 (5.4%), and 15 (10.2%) patients carried mutations of TP53, BRCA1, BRCA2, and PIK3CA mutations. There are also 2, 2 and 3 patients carrying mutations of p.E542K, p.E545K and p.H1047R mutations in PIK3CA , respectively. Mutations in ARID1A (11 patients, 7.4%), NF1 (7, 4.7%) and PTEN (6, 4.1%) can also be detected. In 118 patients received MSI testing, 22 (18.6%) of them are microsatellite instability (MSI)-low.

Conclusions

While BRCA1/2 and HRR related gene is still the most important target for gene test of EOC patient. The high prevalence of other cancer related gene such as PIK3CA cannot be overlooked. Large panel containing more cancer related genes may provide extra suggestions for doctors.