Clinical Outcome and Morphology-Based Analysis of p53 Aberrant and Mismatch Repair Protein-Deficient Ovarian Clear Cell Carcinoma and Their Association With p16, HER2, and PD-L1 Expression.

OBJECTIVES: We studied the prevalence and prognostic significance of mismatch repair deficient (MMRD) and p53 aberrant ovarian clear cell carcinoma (CCO) and their association with other prognostic and theranostic biomarkers (p16, HER2, PD-L1). We also aimed to identify morphologic features to serve as screening tools for immunohistochemical testing for these biomarkers. METHODS: Tissue microarrays with 3-mm cores from 71 pure CCOs were immunostained with PMS2, MSH6, p53, p16, HER2, and PD-L1. Expression status was correlated with tumor recurrence/disease progression and survival. It was also correlated with morphologic features (tumor size, nuclear grade, tumor architecture, mitotic activity, presence of endometriosis, tumor budding, and tumor inflammation). RESULTS: p53 aberrant tumors were associated with shorter overall and recurrence-free survivals (P = .002 and P = .01, respectively). In multivariate analysis, p53 aberrant status and tumor stage were independently associated with recurrence/disease progression (hazard ratio [HR] = 3.31, P = .037 and HR = 1.465, P = .004, respectively). p53 aberrant status was associated with tumor budding (P = .037). MMRD, p16, HER2, and PD-L1 expression had no prognostic significance. HER2 and PD-L1 were expressed in 56% and 35% of tumors, respectively. MMRD was associated with tumor expression of PD-L1 (P > .05) but not with tumor inflammation. CONCLUSIONS: Aberrant p53 in CCO is infrequent but associated with poor prognosis independent of stage. Presence of tumor budding could be a screening tool for p53 testing. High prevalence of HER2 and PD-L1 expression indicates the eligibility of patients with CCO for ongoing clinical trials using these therapeutic targets.

Ovarian Clear Cell Carcinoma and Markers of Epithelial-Mesenchymal Transition (EMT): Immunohistochemical Characterization of Tumor Budding.

Tumor budding, largely considered a manifestation of epithelial-mesenchymal transition (EMT) is an established prognostic marker for several cancers. In a recent study, tumor budding was associated with poor clinical outcomes in early-stage ovarian clear cell carcinoma. Here, we evaluated the immune expression of 3 proteins shown to be associated with EMT (E-cadherin, ß-catenin, and glypican-3) in 72 primary tumors of ovarian clear cell carcinoma with median follow-up of 39.47 mo. E-cadherin and ß-catenin expression was further evaluated in tumor buds in 29 (40%) cases. In the tumor mass, diffuse membranous expression of E-cadherin and ß-catenin was seen in 83% (60/72) and 81% (58/72) cases, respectively. Nuclear accumulation of E-cadherin was seen in 7 (10%) cases, while none of the cases showed nuclear ß-catenin expression. Glypican-3 expression was diffuse in 33.3% (24/72), patchy in 29.2% (21/72), and absent in 37.5% (27/72) cases. Evaluation of tumor buds showed aberrant patterns of expression (complete loss/cytoplasmic accumulation/diminished, discontinuous incomplete membranous staining) of E-cadherin in 29/29 (100%) and of ß-catenin in 26/29 (90%) cases. E-cadherin, ß-catenin, and glypican-3 expression in the main tumor mass had no association with stage, lymph node status, recurrent/progressive disease, status at last follow-up, survival and histopathologic features ( P >0.05). Our finding of aberrant expression of both E-cadherin and ß-catenin in tumor buds indicates involvement of Wnt signaling pathway/EMT in tumor budding and outlines its significance as a prognostic marker especially for early-stage ovarian clear cell carcinoma.

Intratumoral budding is associated with poor clinical outcome in early-stage clear cell carcinoma of ovary.

AIMS: Clear cell carcinoma of ovary (CCC) is considered a high-grade malignancy by default and the role of histological grading for assessing clinical outcome is not established. We aimed to evaluate histopathological features associated with clinical outcome in CCC patients. METHODS AND RESULTS: Seventy-six cases of CCC with available clinical follow-up information were studied. Histopathological features, including tumour size, architectural patterns, nuclear atypia, mitotic activity, intratumoral and peritumoral inflammation, presence of endometriosis, peritumoral and intratumoral budding, were evaluated. Multivariate analysis was performed with logistic regression and Kaplan-Meier survival curves with the log-rank test were used for survival analysis. Forty cases (53%) presented at stage I. Complete response to treatment was achieved in 65%, while 35% of patients had tumour recurrence or progression of disease despite treatment. At last follow-up, 13% had died of disease, 20% were alive with disease and 67% had no evidence of disease. Higher stage (P = 0.0016) and presence of intratumoral budding (P = 0.0454) were independently associated with recurrence/disease progression. Advanced stage (P = 0.0011), presence of lymph node involvement (P = 0.0003), intratumoral budding (P = 0.0023) and peritumoral budding (P = 0.0334) were significantly associated with shorter survival. Intratumoral budding was significantly associated with recurrent/progressive disease (P = 0.0195) and also shorter survival (P = 0.0277) within the cohort of low-stage (I/II) patients as well. CONCLUSION: We have shown that besides the classic prognostic factors of stage and lymph node status, the presence of tumour budding is associated with poorer outcome in patients with CCC. Specifically, evaluation of intratumoral budding may help to more clearly predict prognosis in patients with early-stage disease.