Investigator
Seoul National University
Expression of EGFR, PD‐L1, and the mismatch repair proteins before and following therapy in malignant serous effusions with metastatic high‐grade serous tubo‐ovarian carcinoma
AbstractAimTo compare the immunochemical expression of EGFR, PD‐L1, and the mismatch repair (MMR) proteins MLH1, PMS2, MSH2, and MSH6 between matched malignant effusions obtained before and following the administration of chemotherapy in patients with high‐grade serous tubo‐ovarian carcinoma (HGSC).MethodsIn the enrolled HGSCs, matched formalin‐fixed and paraffin‐embedded cell blocks (CBs) from effusions sampled before (treatment‐naïve patients) and during recurrence (following chemotherapy administration), in addition to their matched HGSC tissues obtained from the ovaries at initial diagnosis (treatment‐naïve patients), were subjected to EGFR, PD‐L1, and MMR immunochemical analysis.ResultsEGFR was more often overexpressed in effusions obtained after chemotherapy administration compared to both effusions (100% vs. 57.1%) and their matched tubo‐ovarian tumors (100% vs. 7.1%) from treatment‐naïve patients, respectively. EGFR immunochemistry was concordant in just 9.1% of the effusions sampled during recurrence and their paired ovarian samples before recurrence. Whereas all HGSC treatment‐naïve samples (ovarian lesions and effusions) were PD‐L1 negative, 3/11 (27.3%) malignant effusions obtained during recurrence showed PD‐L1 overexpression. Lastly, none of the tested HGSC samples exhibited MMR deficiency.ConclusionMeasuring biomarkers using CBs from malignant effusions may provide clinicians with significant information related to HGSC prognosis and therapy selection, especially in patients with resistance to chemotherapy.
Biomarkers expression among paired serous ovarian cancer primary lesions and their peritoneal cavity metastases in treatment‐naïve patients: A single‐center study
AbstractBackgroundHigh‐grade serous ovarian carcinoma (HGSOC), the most common histologic subtype of ovarian epithelial cancer, is associated with treatment resistance, enhanced recurrence rates, and poor prognosis. HGSOCs often metastasize to the peritoneal cavity, while fluid cytology examination could identify such metastases. This retrospective study aimed to identify potential biomarker discrepancies between paired HGSOC primary tissues and metastatic peritoneal fluid cytology samples, processed as cell blocks (CBs).MethodsTwenty‐four pairs of formalin‐fixed, paraffin‐embedded primary tissues and metastatic CBs from an equal number of treatment‐naïve patients were used, and immunohistochemistry (IHC) for epidermal growth factor receptor (EGFR), human epidermal growth factor receptor, programmed cell death‐1 ligand 1 (PD‐L1), and CD147 was applied.Results13/24 pairs showed discordant EGFR IHC results; in all these 13 patients, EGFR was positive (≥1+ membranous staining intensity found in at least 10% of the cancer cells) in the peritoneal, yet negative in the primary tissue samples. Notably, EGFR IHC was positive in 15/24 of the metastatic, whereas in just 2/24 of the primary HGSOC samples (p < 0.001). Although most PD‐L1 results were concordant, 5/24 and 6/24 pairs exhibited discordant results when stained with the E1L3N and 22C3 clones, respectively. Lastly, CD147 overexpression was found more often in the metastatic rather than the matched primary HGSOCs stained with CD147, though the difference was not significant.ConclusionsCytology from effusions could be considered for biomarker testing when present, even when tissue from the primary cancer is also available and adequately cellular, as it could provide additional information of potential clinical significance.
