[Application and clinical significance of TCGA molecular classification in endometrial cancer]

Objective: To explore the application and clinical significance of the cancer genome atlas (TCGA) molecular classification in endometrial cancer (EC). Methods: Sixty-six EC patients collected from December 2018 to March 2021 from Peking University People's Hospital were categorized into four subgroups based on TCGA molecular classification tested by next generation sequencing. The correlation among four molecular subgroups and the clinical-pathological features including prognosis were analyzed. Results: (1) Clinical and pathological features: median age at diagnosis was 56 years (range: 24-78 years). The cases were distributed as follows: 3 (5%) cases DNA polymerase epsilon (POLE) ultra-mutated, 11 (17%) cases high microsatellite instability (MSI-H) including 2 Lynch syndrome, 42 (64%) cases low copy-number (CN-L) and 10 (15%) cases high copy-number (CN-H). There were significant differences among four subtypes in the combination of other tumors, tumor family history, surgical method, International Federation of Gynecology and Obstetrics (FIGO, 2009) stage, depth of muscle invasion and lymph vascular space invasion (all P<0.05). The proportions of patients in CN-H subgroup with advanced FIGO stage (stage Ⅲ-Ⅳ), deep muscle invasion and positive lymph-vascular space invasion were significantly increased. There were no significant differences in age, menopausal status, body mass index, metabolic syndrome-related complications, preoperative serum CA₁₂₅ and human epididymis protein 4 levels, tumor size, pathological grade (only endometrioid cancer), and lymph node metastasis among the 4 TCGA molecular types (all P>0.05). (2) Immuno-related molecular analysis: among 66 EC patients, 27 patients underwent immunohistochemical analysis of programmed cell death 1 ligand 1 (PD-L1) protein, and 28 patients underwent tumor mutation burden (TMB) detection. POLE and MSI-H subgroups contained TMB than those in CN-L and CN-H (P<0.05).(3) Prognosis: the median follow-up time was 10 months (range: 0-28 months). The progression-free survival rate of TCGA molecular types were 100% (POLE ultra-mutated), 100% (MSI-H), 98% (CN-L), and 80% (CN-H) respectively and had significant differences (P=0.034). The overall survival were 100% (POLE ultra-mutated), 100% (MSI-H), 98% (CN-L), and 90% (CN-H) respectively, but there were not statistically significant difference (P=0.361). POLE ultra-mutated and MSI-H subgroups had the best survival, while CN-H had the worst. Conclusion: TCGA molecular classification has feasibility and clinical value in clinical application of EC, which is helpful to identify the prognosis of patients.