Molecular Evaluation of Low-grade Low-stage Endometrial Cancer With and Without Recurrence

Endometrioid Endometrial RNA Index Predicts Recurrence in Stage I Patients

PURPOSE

Risk prediction with genomic and transcriptomic data has the potential to improve patient outcomes by enabling clinicians to identify patients requiring adjuvant treatment approaches, while sparing low-risk patients from unnecessary interventions. Endometrioid endometrial carcinoma (EEC) is the most common cancer in women in developed countries, and rates of endometrial cancer are increasing.

EXPERIMENTAL DESIGN

We collected a 105-patient case-control cohort of stage I EEC comprising 45 patients who experienced recurrence less than 6 years after excision, and 60 Fédération Internationale de Gynécologie et d'Obstétrique grade-matched controls without recurrence. We first utilized two RNA-based, previously validated machine learning approaches, namely, EcoTyper and Complexity Index in Sarcoma (CINSARC). We developed Endometrioid Endometrial RNA Index (EERI), which uses RNA expression data from 46 genes to generate a personalized risk score for each patient. EERI was trained on our 105-patient cohort and tested on a publicly available cohort of 263 patients with stage I EEC.

RESULTS

EERI was able to predict recurrences with 94% accuracy in the training set and 81% accuracy in the test set. In the test set, patients assigned as EERI high-risk were significantly more likely to experience recurrence (30%) than the EERI low-risk group (1%) with a hazard ratio of 9.9 (95% CI, 4.1-23.8; P < 0.001).

CONCLUSIONS

Tumors with high-risk genetic features may require additional treatment or closer monitoring and are not readily identified using traditional clinicopathologic and molecular features. EERI performs with high sensitivity and modest specificity, which may benefit from further optimization and validation in larger independent cohorts.

Explore the alterations of downstream molecular pathways caused by ARID1A mutation/knockout in human endometrial cancer cells

PURPOSE

As one of the most common gynecologic malignancies, endometrial cancer (EC) is driven by multiple genetic alterations that may be targeted for treatments. AT-rich interaction domain 1A (ARID1A) gene mutations were reported as early events in endometrial carcinogenesis.

METHODS

To explore the alterations of downstream molecular pathways caused by ARID1A mutations and the associated therapeutic implications, we edited ARID1A gene in human endometrial cancer cell line Ishikawa using the Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-Associated Proteins (CRISPR/Cas9) technology. We successfully constructed a stable Ishikawa cell line with a confirmed 10 bp deletion on the ARID1A gene, which resulted in a code-shift mutation and gene knockout.

RESULTS

Compared with unedited wild-type cells, ARID1A knockout (KO) led to reduced apoptosis, accelerated transformation from G0/G1 to S phase, and enhanced cell proliferation. ARID1A deficiency would reduce the protein levels of p21, caspase 7, and caspase 9 in Ishikawa endometrial cancer cells compared with the wild-type cells. In addition, ARID1A KO resulted in high levels of microsatellite instability (MSI-H). Moreover, transcriptomic analyses showed that ARID1A KO can lead to activated phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling. Furthermore, experimental analyses demonstrated that ARID1A KO cells had reduced expression of genetic instability-associated markers mutL homologue 1 (MLH1) and progesterone receptor B (PR) and increased p-Akt expression.

CONCLUSION

These findings support further exploration of ARID1A as a therapeutic target for EC and provide insight into developing more effective treatments in EC, such as the combinatory use of immune checkpoint inhibitors.

[Molecular classification of endometrial carcinoma-a short summary for clinical use]

BACKGROUND

Histopathological examination is still the backbone for the diagnosis and treatment decision making in endometrial carcinoma (EC). The binary classification of EC into type 1 (mostly endometrioid) and type 2 (mostly serous), although still helpful, showed overlapping clinical, morphological and molecular features and was not very prognostic discriminatory for all subtypes of EC.

METHODS

Analysing the most recent studies dealing with the molecular classification of EC and the recommendations of the German S3-guidelines for EC.

RESULTS AND CONCLUSION

Based on the comprehensive molecular study of The Cancer Genome Atlas Project (TCGA) four distinct molecular subtypes have been identified: EC with POLE mutation (POLEmut), with loss of mismatch repair proteins (MMR deficiency; dMMR), or with TP53 mutation (p53mut) and without any of these alterations, termed NSMP (no specific molecular profile). The molecular classification of EC presents a morphomolecular approach, based on histopathological evaluation (tumor diagnosis, subtyping, grading), immunohistochemistry (MMR, p53) and molecular analyses for POLE. The incorporation of this molecular classification is recommended for clinical use by the World Health Organisation (WHO) as well as many national guidelines and international societies. Due to the heterogeneity of NSMP-EC, which is the largest molecular group, additional research is indicated to further characterise these tumors.

Genomic Determinants of Early Recurrences in Low-Stage, Low-Grade Endometrioid Endometrial Carcinoma

Low-stage, low-grade endometrioid endometrial carcinoma (EEC), the most common histologic type of endometrial cancer, typically has a favorable prognosis. A subset of these cancers, however, displays an aggressive clinical course with early recurrences, including distant relapses. All statistical tests were 2-sided. Using a combination of whole-exome and targeted capture sequencing of 65 FIGO stage IA and IB grade 1 EECs treated with surgery alone, we demonstrate that chromosome 1q gain (odds ratio [OR] = 8.09, 95% confidence interval [CI] = 1.59 to 54.6; P = .02), PIK3CA mutation (OR = 9.16, 95% CI = 1.95 to 61.8; P = .01), and DNA mismatch repair-deficient molecular subtype (OR = 7.92, 95% CI = 1.44 to 87.6; P = .02) are independent predictors of early recurrences within 3 years in this patient population. Chromosome 1q gain was validated in an independent dataset of stage I grade 1 EECs subjected to whole-exome sequencing. Our findings expand on the repertoire of genomic parameters that should be considered in the evaluation of patients with low-stage, low-grade EEC.