Genomic Sub-Classification of Ovarian Clear Cell Carcinoma Revealed by Distinct Mutational Signatures

Area of Science:

• Oncology
• Genomics
• Molecular Biology

Background:

• Ovarian clear cell carcinoma (OCCC) has a poor prognosis and chemoresistance.
• OCCC exhibits unique molecular alterations compared to other ovarian cancer subtypes.

Purpose of the Study:

• To identify patient subgroups within OCCC.
• To characterize the molecular features and mutational signatures of these subgroups.
• To explore potential clinical relevance for targeted therapies.

Main Methods:

• Analysis of mutational profiles using a 409-gene panel in 55 OCCC patients.
• Assessment of genomic instability via microsatellite assay.
• Identification of molecular subgroups and their associated mutational signatures using COSMIC.

Main Results:

• ARID1A (49.1%) and PIK3CA (41.8%) mutations were the most frequent.
• Co-occurrence of ARID1A and PIK3CA mutations was observed in 36.1% of patients.
• Three distinct molecular subgroups were identified: 'PIK3CA', 'Double hit' (ARID1A/PIK3CA), 'ARID1A', and 'Undetermined', each with unique mutational signatures.

Conclusions:

• OCCC exhibits diverse mutational landscapes, suggesting potential for subgroup-specific therapeutic approaches.
• The identified molecular subgroups may inform personalized treatment strategies.
• Further validation in larger cohorts is necessary to confirm these findings.