Viktor Hlaváč

Targeted DNA sequencing of high‐grade serous ovarian carcinoma reveals association of TP53 mutations with platinum resistance when combined with gene expression

AbstractHigh‐grade serous ovarian carcinoma (HGSC) is the most common subtype of ovarian cancer and is among the most fatal gynecological malignancies worldwide, due to late diagnosis at advanced stages and frequent therapy resistance. In 47 HGSC patients, we assessed somatic and germline genetic variability of a custom panel of 144 known or suspected HGSC‐related genes by high‐coverage targeted DNA sequencing to identify the genetic determinants associated with resistance to platinum‐based therapy. In the germline, the most mutated genes were DNAH14 (17%), RAD51B (17%), CFTR (13%), BRCA1 (11%), and RAD51 (11%). Somatically, the most mutated gene was TP53 (98%), followed by CSMD1/2/3 (19/19/36%), and CFTR (23%). Results were compared with those from whole exome sequencing of a similar set of 35 HGSC patients. Somatic variants in TP53 were also validated using GENIE data of 1287 HGSC samples. Our approach showed increased prevalence of high impact somatic and germline mutations, especially those affecting splice sites of TP53, compared to validation datasets. Furthermore, nonsense TP53 somatic mutations were negatively associated with patient survival. Elevated TP53 transcript levels were associated with platinum resistance and presence of TP53 missense mutations, while decreased TP53 levels were found in tumors carrying mutations with predicted high impact, which was confirmed in The Cancer Genome Atlas data (n = 260). Targeted DNA sequencing of TP53 combined with transcript quantification may contribute to the concept of precision oncology of HGSC. Future studies should explore targeting the p53 pathway based on specific mutation types and co‐analyze the expression and mutational profiles of other key cancer genes.

Whole-exome sequencing of epithelial ovarian carcinomas differing in resistance to platinum therapy

Epithelial ovarian carcinoma (EOC) is highly fatal because of the risk of resistance to therapy and recurrence. We performed whole-exome sequencing of blood and tumor tissue pairs of 50 patients with surgically resected EOC. Compared with sensitive patients, platinum-resistant patients had a significantly higher somatic mutational rate inTP53and lower in several genes from the Hippo pathway. We confirmed the pivotal role of somatic mutations in homologous recombination repair genes in platinum sensitivity and favorable prognosis of EOC patients. Implementing the germline homologous recombination repair profile significantly improved the prediction. In addition, distinct mutational signatures, for example, SBS6, and overall mutational load, somatic mutations inPABPC1,PABPC3, andTFAMco-segregated with the resistance status, high-grade serous carcinoma subtype, or overall survival of patients. We generated germline and somatic genetic landscapes of prognostically different subgroups of EOC patients for further follow-up studies focused on utilizing the observed associations in precision oncology.

Molecular Classification in Relation to Prevention of Endometrial Cancer Recurrence and Lifestyle Factors

Endometrial cancer (EC) is one of the most prevalent cancers in women worldwide with a significantly increasing incidence, especially in developed countries. One of the reasons for the increase in the incidence of this disease is the rising incidence of obesity as the biggest risk factor for the development of this disease. Other important risk factors are hypertension, diabetes mellitus and the general ageing of the population. These risk factors are not only associated with a higher risk of developing the disease, but also, for example, with post-operative complications affecting the quality of life of patients after surgery. The molecular classification of endometrial cancer, which has been introduced into clinical practice in recent years, is currently helping physicians to make treatment decisions for individual patients and predict prognosis. In this project, we would like to focus on the relationship of this molecular classification with genomic mutational signatures detected by whole-exome sequencing and their association with lifestyle risk factors for endometrial cancer (obesity - BMI, hypertension, diabetes mellitus), including the extent of staging lymphadenectomy. Identification and detailed analysis of dominant mutational profiles associated with a specific molecular subtype of EC and their influence on the presence of lifestyle risk factors may have a major impact on both disease development and prevention of disease recurrence. The possible relationship of the mutational profile with the extent of staging lymphadenectomy may help in deciding the extent of this surgical procedure, which subsequently affects the quality of life of patients, especially in patients with high BMI. Given the widespread prevalence of lifestyle risk factors in the developed world, a detailed understanding of the relationship between the genetic profile, its alterations and the prevalence of these risk factors, with potentially major implications for treatment success, is crutial.