Uncommon Human Telomerase Reverse Transcriptase Promoter Mutations Are Associated With Poor Survival in Ovarian Clear Cell Carcinoma

Suppressor-type TERT mutations associated with recurrence in ovarian clear cell carcinoma

Several cancers harbor "enhancer-type" mutations of the telomerase reverse transcriptase (TERT) promoter for immortalization. Here, we report that 8.6% (8/93) of ovarian clear cell carcinomas (OCCCs) possess the "suppressor-type" TERT promoter mutation. The recurrence rate of OCCCs with "suppressor-type" TERT promoter mutations was 62.5% (5/8) and was significantly higher than that of the "unaffected-type" with no mutation (20.8%, 15/72) or "enhancer-type" TERT promoter mutations (7.7%, 1/13). Our findings show that the acquired suppression of TERT is closely associated with OCCC development and recurrence, indicating the need for further research on telomerase suppression in cancers.

A comprehensive molecular analysis of 113 primary ovarian clear cell carcinomas reveals common therapeutically significant aberrations

BACKGROUND

Molecular aberrations occurring in primary ovarian clear cell carcinoma (OCCC) can be of diagnostic, predictive, and prognostic significance. However, a complex molecular study including genomic and transcriptomic analysis of large number of OCCC has been lacking.

METHODS

113 pathologically confirmed primary OCCCs were analyzed using capture DNA NGS (100 cases; 727 solid cancer related genes) and RNA-Seq (105 cases; 147 genes) in order to describe spectra and frequency of genomic and transcriptomic alterations, as well as their prognostic and predictive significance.

RESULTS

The most frequent mutations were detected in genes ARID1A, PIK3CA, TERTp, KRAS, TP53, ATM, PPP2R1A, NF1, PTEN, and POLE (51,47,27,18,13,10,7,6,6, and 4%, respectively). TMB-High cases were detected in 9% of cases. Cases with POLE^mut and/or MSI-High had better relapse-free survival. RNA-Seq revealed gene fusions in 14/105 (13%) cases, and heterogeneous expression pattern. The majority of gene fusions affected tyrosine kinase receptors (6/14; four of those were MET fusions) or DNA repair genes (2/14). Based on the mRNA expression pattern, a cluster of 12 OCCCs characterized by overexpression of tyrosine kinase receptors (TKRs) AKT3, CTNNB1, DDR2, JAK2, KIT, or PDGFRA (p < 0.00001) was identified.

CONCLUSIONS

The current work has elucidated the complex genomic and transcriptomic molecular hallmarks of primary OCCCs. Our results confirmed the favorable outcomes of POLE^mut and MSI-High OCCC. Moreover, the molecular landscape of OCCC revealed several potential therapeutical targets. Molecular testing can provide the potential for targeted therapy in patients with recurrent or metastatic tumors.

Molecular Landscape of Mullerian Clear Cell Carcinomas Identifies The Cancer Genome Atlas-like Prognostic Subgroups

Mullerian clear cell carcinoma (CCC) is often aggressive and chemoresistant. The prognostic significance of molecular subclassification of endometrioid carcinomas is well established. However, less is known about the molecular landscape of CCC. The aim of this study was to better characterize the genetic landscape of a large cohort of CCC and correlate these findings with clinicopathologic features. CCC of the ovary (n = 72), endometrium (n = 24), and peritoneum/abdominal wall (n = 5) were retrospectively identified. Tumors had undergone tumor-only targeted sequencing using a hybrid capture next-generation sequencing panel. Median tumor mutational burden was 6.8 mutations/megabase (range, 1.3-185, 21% were ≥10 mutations/Mb). The most frequently mutated genes were ARID1A (48%), PIK3CA (45%), TP53 (23%), and PTEN (10%). ERBB2 amplification occurred in 4%. When classified according to the Cancer Genome Atlas/the Proactive Molecular Risk Classifier for Endometrial Cancer endometrial carcinoma molecular subgroups, 3 (3%) were POLE ultramutated, 5 (5%) were microsatellite instability-high (MSI-H), 20 (20%) were TP53-mutant subgroup, and 73 (72%) were no specific molecular profile (NSMP). Immunohistochemical expression of estrogen receptor, progesterone receptor, and programmed death-ligand 1 were not associated with the molecular subgroup. POLE and MSI-H tumors were characterized by an excellent prognosis, and the TP53-mutant subgroup had a worse disease-free survival than NSMP. NSMP tumors could be further substratified as high-risk NSMP if they lacked PIK3CA, PIK3R1, and ARID1A mutations, and/or harbored a TERT-promoter mutation. The Cancer Genome Atlas and NSMP-specific stratifications were prognostic for both the entire cohort and the subset of stage I ovarian tumors. On multivariable analysis, stage, lymphovascular invasion, and tumor mutational burden were prognostic for disease-free survival, whereas advanced stage and TP53-mutant subgroup - but not a TP53 mutation in isolation - were negative prognostic factors for overall survival. These data suggest that routine molecular profiling of Mullerian CCC may be warranted for both prognosis and identification of potential targeted treatments, such as immunotherapy and anti-HER2 agents.

Clear cell carcinoma of the ovary: a clinical and molecular perspective

Clear cell carcinoma of the ovary has distinct biology and clinical behavior. There are significant geographical and racial differences in the incidence of clear cell carcinoma compared with other epithelial ovarian tumors. Patients with clear cell carcinoma are younger, tend to present at an early stage, and their tumors are commonly associated with endometriosis, which is widely accepted as a direct precursor of clear cell carcinoma and has been identified pathologically in approximately 50% of clear cell carcinoma cases. The most frequent and important specific gene alterations in clear cell carcinoma are mutations of AT-rich interaction domain 1A (ARID1A) (~50% of cases) and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) (~50% cases). More broadly, subgroups of clear cell carcinoma have been identified based on C-APOBEC (apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like) and C-AGE (age-related) mutational signatures. Gene expression profiling shows upregulation of hepatocyte nuclear factor 1-beta (HNF1β) and oxidative stress-related genes, and has identified epithelial-like and mesenchymal-like tumor subgroups. Although the benefit of platinum-based chemotherapy is not clearly defined it remains the mainstay of first-line therapy. Patients with early-stage disease have a favorable clinical outcome but the prognosis of patients with advanced-stage or recurrent disease is poor. Alternative treatment strategies are required to improve patient outcome and the development of targeted therapies based on molecular characteristics is a promising approach. Improved specificity of the histological definition of this tumor type is helping these efforts but, due to the rarity of clear cell carcinoma, international collaboration will be essential to design appropriately powered, large-scale clinical trials.

Genomic profiling of primary and recurrent adult granulosa cell tumors of the ovary

Adult-type granulosa cell tumor (aGCT) is a rare malignant ovarian sex cord-stromal tumor, harboring recurrent FOXL2 c.C402G/p.C134W hotspot mutations in 97% of cases. These tumors are considered to have a favorable prognosis, however aGCTs have a tendency for local spread and late recurrences, which are associated with poor survival rates. We sought to determine the genetic alterations associated with aGCT disease progression. We subjected primary non-recurrent aGCTs (n = 7), primary aGCTs that subsequently recurred (n = 9) and their matched recurrences (n = 9), and aGCT recurrences without matched primary tumors (n = 10) to targeted massively parallel sequencing of ≥410 cancer-related genes. In addition, three primary non-recurrent aGCTs and nine aGCT recurrences were subjected to FOXL2 and TERT promoter Sanger sequencing analysis. All aGCTs harbored the FOXL2 C134W hotspot mutation. TERT promoter mutations were found to be significantly more frequent in recurrent (18/28, 64%) than primary aGCTs (5/19, 26%, p = 0.017). In addition, mutations affecting TP53, MED12, and TET2 were restricted to aGCT recurrences. Pathway annotation of altered genes demonstrated that aGCT recurrences displayed an enrichment for genetic alterations affecting cell cycle pathway-related genes. Analysis of paired primary and recurrent aGCTs revealed that TERT promoter mutations were either present in both primary tumors and matched recurrences or were restricted to the recurrence and absent in the respective primary aGCT. Clonal composition analysis of these paired samples further revealed that aGCTs display intra-tumor genetic heterogeneity and harbor multiple clones at diagnosis and relapse. We observed that in a subset of cases, recurrences acquired additional genetic alterations not present in primary aGCTs, including TERT, MED12, and TP53 mutations and CDKN2A/B homozygous deletions. Albeit harboring relatively simple genomes, our data provide evidence to suggest that aGCTs are genetically heterogeneous tumors and that TERT promoter mutations and/or genetic alterations affecting other cell cycle-related genes may be associated with disease progression and recurrences.