INTRODUCTION: Ovarian cancer is one of the leading causes of mortality in women. In 2020, 5,395 (6.2%) of diagnosed malignancies in females were ovarian in origin. It also ranked second among gynecologic malignancies after cervical cancer. The prevalence in Asian /Pacific women is 9.2 per 100,000 population. Increased mortality and poor prognosis in ovarian cancer are caused by asymptomatic growth and delayed or absent symptoms for which about 70% of women have an advanced stage (III/IV) by the time of diagnosis. The most associated gene mutations are Breast Cancer gene 1 (BRCA1) which is identified in chromosome 17q21 and Breast Cancer gene 2 (BRCA2) identified in chromosome 13. Both proteins function in the double-strand DNA break repair pathway especially in the large framework repair molecules. Olaparib is a first-line drug used in the management of ovarian cancer. It targets affected cells by inhibition of poly (ADP-ribose) polymerase (PARP) activity which induces synthetic lethality in mutated BRCA1/2 cancers by selectively targeting tumor cells that fail to repair DNA double-strand breaks (DSBs). OBJECTIVE: The study aims to determine the prevalence of pathogenic somatic mutations in BRCA1 and BRCA2 among patients diagnosed of having ovarian cancer, to characterize the identified variants into benign/ no pathogenic variant identified, variant of uncertain significance (VUS), and pathogenic, and to determine the relationship of specific mutations detected with histomorphologic findings and clinical attributes. METHODOLOGY: Ovarian cancer tissues available at the St. Luke’s Medical Center Human Cancer Biobank and formalin-fixed paraffin-embedded (FFPE) tissue blocks diagnosed as ovarian cancer from the year 2016 to 2020 were included. Determination of the prevalence of somatic BRCA1 and BRCA2 mutations using Next Generation Sequencing (NGS). RESULTS: A total of 60 samples were processed, and three samples were excluded from the analysis due to an inadequate number of cells. In the remaining 57 samples diagnosed ovarian tumors, pathogenic BRCA1/2 variants were identified in 10 (17.5%) samples. Among the BRCA1/2 positive samples, 3 (5.3%) BRCA1 and 7 (12.3%) BRCA2 somatic mutations were identified. CONCLUSION Identification of specific BRCA1/2 mutations in FFPE samples with NGS plays a big role in the management of ovarian cancer, particularly with the use of targeted therapies such as Olaparib. The use of this drug could provide a longer disease-free survival for these patients. Furthermore, we recommend that women diagnosed with ovarian cancer should be subjected to genetic testing regardless of the histologic subtypes or clinical features. Lastly, genetic testing should be done along with proper genetic counseling, especially for patients who are susceptible to these mutations.
ovarian cancer

Background: Gastrointestinal stromal tumors (GIST) is defined as specific, typically kit (CD117)-positive and CKIT or platelet-derived growth factor receptor alpha (PDGFRA) mutation-driven mesenchymal tumors that can occur anywhere in the GI tract. GIST diagnosis relies heavily on immunohistomorphology. However, with the advent of molecular testing, the classification, diagnosis and targeted-therapy for gastrointestinal mesenchymal tumors have been greatly improved. In the Philippines, molecular testing is not yet readily available as in other countries. The local molecular profile of gastrointestinal stromal tumors is a point of investigation as treatment may be more tailored to the patients’ needs. Objective: This study aims to determine the prevalence of CKIT and PDGFRA mutations among formalin-fixed and paraffin embedded gastrointestinal stromal tumors and other gastrointestinal mesenchymal tumors in St. Luke’s Medical Center – Quezon City. Methods: A retrospective cross-sectional study of formalin fixed and paraffin embedded tumor samples diagnosed as Gastrointestinal Stromal Tumor from January 1, 2009 to December 31, 2017 will be analyzed for KIT and PDGFRA mutations. Result: The epidemiology of GIST remains constant in that mean age group is the 5th to 6th decade, with equal gender distribution, and stomach followed by small bowel are the most common sites. Mutational analysis of the GISTs showed predominantly KIT Exon 11 (47.83%) followed by CKIT Exon 9 (13.04%) and PDGFRA Exon 18 (10.87%). For KIT Exon 11, deletion is the most common mutations followed by point mutations. No mutation is detected in 47.83% of GISTs. Conclusion Mutational analysis for CKIT-PDGFRA is warranted among GIST patients, as it may significantly influence treatment protocol in our patients.
Gastrointestinal Stromal Tumors