Dissecting the Origin of Heterogeneity in Uterine and Ovarian Carcinosarcomas

Molecular characteristics of tubo-ovarian carcinosarcoma at different anatomic locations

Carcinosarcoma (CS) is an uncommon and clinically aggressive malignancy. The objective of the present study was to characterize the molecular features of CS at various anatomic locations, including serous effusions. Specimens (n = 32) consisted of 25 biopsies/surgical resection specimens and 7 serous effusions (6 peritoneal, 1 pleural) from 25 patients. Fresh-frozen cell pellets and surgical specimens underwent targeted next-generation sequencing covering 50 unique genes. A total of 31 mutations were found in 25 of the 32 tumors studied, of which 1 had 3 mutations, 4 had 2 different mutations, and 20 had a single mutation. The most common mutations were in TP53 (n = 25 in 24 tumors; 1 tumor with 2 different mutations), with less common mutations found in RB1 (n = 2), MET (n = 1), KRAS (n = 1), PTEN (n = 1), and KIT (n = 1). Patient-matched specimens harbored the same TP53 mutation. Tumors with no detected mutations were more common in serous effusion specimens (3/7; 43%) compared with surgical specimens (4/25; 16%). In conclusion, the molecular landscape of CS is dominated by TP53 mutations, reinforcing the observation that the majority of these tumors develop from high-grade serous carcinoma. Whether CS cells in serous effusions differ from their counterparts in solid lesions remains uncertain.

Compartment-specific multiomic profiling identifies SRC and GNAS as candidate drivers of epithelial-to-mesenchymal transition in ovarian carcinosarcoma

BACKGROUND

Ovarian carcinosarcoma (OCS) is an exceptionally aggressive and understudied ovarian cancer type harbouring distinct carcinomatous and sarcomatous compartments. Here, we seek to identify shared and compartment-specific events that may represent potential therapeutic targets and candidate drivers of sarcomatous compartment formation through epithelial-to-mesenchymal transition (EMT).

METHODS

We performed multiomic profiling (exome sequencing, RNA-sequencing, microRNA profiling) of paired carcinomatous and sarcomatous components in 12 OCS cases.

RESULTS

While paired sarcomatous and carcinomatous compartments demonstrate substantial genomic similarities, multiple loci are recurrently copy number-altered between components; regions containing GNAS and SRC are recurrently gained within the sarcomatous compartment. CCNE1 gain is a common event in OCS, occurring more frequently than in high grade serous ovarian carcinoma (HGSOC). Transcriptomic analysis suggests increased MAPK activity and subtype switching toward poor prognosis HGSOC-derived transcriptomic subtypes within the sarcomatous component. The two compartments show global differences in microRNA profiles, with differentially expressed microRNAs targeting EMT-related genes (SIRT1, ZEB2) and regulators of pro-tumourigenic pathways (TGFβ, NOTCH); chrX is a highly enriched target of these microRNAs and is also frequently deleted across samples. The sarcomatous component harbours significantly fewer CD8-positive cells, suggesting poorer immune engagement.

CONCLUSION

CCNE1 gain and chrX loss are frequent in OCS. SRC gain, increased GNAS expression and microRNA dysregulation represent potential mechanisms driving sarcomatous compartment formation.

Prognostic Value of Lymph Node Ratio in Patients with Uterine Carcinosarcoma

Uterine carcinosarcoma is a rare high-grade endometrial cancer. Controversy has surrounded a number of aspects in the diagnosis and management of this unique clinicopathological entity, including the efficacy of adjuvant therapy, which has been questioned. An unusual surgico-pathological parameter with prognostic significance in a number of tumour sites is the lymph node ratio (LNR). The availability of data in this respect has been scarce in the literature. The primary aim of this collaborative study was to evaluate the prognostic value of LNR in patients with uterine carcinosarcoma. LNR is a recognized lymph node metric used to stratify prognosis in a variety of malignancies. In this European multinational retrospective study, 93 women with uterine carcinosarcoma were included in the final analysis. We used t-tests and ANOVA for comparison between quantitative variables between the groups, and chi-square tests for qualitative variables. A multivariate analysis using Cox regression analysis was performed to determine potential prognostic factors, including the LNR. Patients were grouped with respect to LNR in terms of 0%, 20% > 0% and >20%. The analysis revealed LNR to be a significant predictor of progression-free survival (HR 1.69, CI (1.12-2.55), p = 0.012) and overall survival (HR 1.71, CI (1.07-2.7), p = 0.024). However, LNR did not remain a significant prognostic factor on multivariate analysis. Due to limitations of the retrospective study, a prospective large multinational study, which takes into effect the most recent changes to clinical practice, is warranted to elucidate the value of the pathophysiological metrics of the lymphatic system associated with prognosis.