Mieke R Van Bockstal

Stemness in high-grade serous carcinoma of tubo-ovarian origin causes multiple immunohistochemical pitfalls: a case report

Immunologic impact of chemoradiation in cervical cancer and how immune cell infiltration could lead toward personalized treatment

We investigated the potential of tumor‐infiltrating immune cells (ICs) as predictive or prognostic biomarkers for cervical cancer patients. In total, 38 patients treated with (chemo)radiotherapy and subsequent surgery were included in the current study. This unique treatment schedule makes it possible to analyze IC markers in pretreatment and posttreatment tissue specimens and their changes during treatment. IC markers for T cells (CD3, CD4, CD8 and FoxP3), macrophages (CD68 and CD163) and B cells (CD20), as well as IL33 and PD‐L1, were retrospectively analyzed via immunohistochemistry. Patients were grouped in the low score or high score group based on the amount of positive cells on immunohistochemistry. Correlations to pathological complete response (pCR), cause‐specific survival (CSS) and metastasis development during follow‐up were evaluated. In analysis of pretreatment biopsies, significantly more pCR was seen for patients with CD8 = CD3, CD8 ≥ CD4, positive IL33 tumor cell (TC) scores, IL33 IC < TC and PD‐L1 TC ≥5%. Besides patients with high CD8 scores, also patients with CD8 ≥ CD4, CD163 ≥ CD68 or PD‐L1 IC ≥5% had better CSS. In the analysis of posttreatment specimens, less pCR was observed for patients with high CD8 or CD163 scores. Patients with decreasing CD8 or CD163 scores between pretreatment and posttreatment samples showed more pCR, whereas those with increasing CD8 or decreasing IL33 IC scores showed a worse CSS. Meanwhile, patients with an increasing CD3 score or stable/increasing PD‐L1 IC score showed more metastasis during follow‐up. In this way, the intratumoral IC landscape is a promising tool for prediction of outcome and response to (chemo)radiotherapy.

Use of p53 immunohistochemistry can improve diagnostic agreement for differentiated vulvar intraepithelial neoplasia ( dVIN ): an international reproducibility study

Aims Differentiated or HPV‐independent vulvar intraepithelial neoplasia (dVIN) can progress rapidly to invasive cancer and accurate pathological diagnosis is essential to facilitate appropriate interventions. Histological similarities of dVIN with non‐neoplastic lesions, however, often make the diagnosis less reproducible. We investigated among a diverse group of pathologists whether the diagnostic agreement improves with the use of p53 immunohistochemistry (IHC) interpreted using the pattern‐based schema. Methods and results Fifty haematoxylin–eosin (HE) stained archival slides (30 dVIN and 20 non‐dysplastic vulvar lesions) were selected and p53‐IHC was performed. Twenty‐four board‐certified pathologists from eight countries first assessed the HE slides alone, and after a washout period, re‐evaluated them alongside the p53‐IHC slides. During both rounds, slides were diagnosed as dVIN, favour dVIN, favour no‐VIN or no‐VIN. p53‐IHC was scored as wild‐type or mutant (diffuse, basal, cytoplasmic or null). Kappa ( κ ) statistics and McNemar's test were used for statistical analyses. Overall diagnostic agreement for dVIN saw a significant increase in the Kappa value ( κ  = 0.6 vs. κ  = 0.4, P  = 0.002) when HE and p53‐IHC slides were assessed together compared with histology assessment alone, although the level of agreement remained moderate. For p53‐IHC assessment, overall agreement was substantial ( κ  = 0.7). Diagnoses changing from no‐VIN/favour no‐VIN to dVIN correlated significantly with the identification of a p53‐mutant pattern ( P  < 0.001). Conclusions Our findings indicate that p53‐IHC is a robust ancillary tool that can be reproducibly interpreted by pathologists with varying experience levels and supports the routine use of p53‐IHC in cases where dVIN is considered in the differential diagnosis.