Antonio d’Amati

Interobserver Agreement in Immunohistochemical Evaluation of Folate Receptor Alpha (FRα) in Ovarian Cancer: A Multicentre Study

Folate receptor alpha (FRα) is a high-affinity folate transporter overexpressed in various epithelial malignancies, particularly high-grade serous ovarian carcinoma. Given its restricted expression in normal tissues and accessibility in tumors, FRα is an emerging therapeutic target. Immunohistochemistry (IHC) is the standard method for FRα assessment; however, interpretation is semi-quantitative and prone to interobserver variability. This study aimed to evaluate interobserver agreement among 12 pathologists in the IHC assessment of FRα in ovarian cancer, focusing on internal control adequacy, staining intensity, and the percentage of FRα-positive tumor cells. Thirty-seven high-grade serous ovarian carcinoma cases were stained using the VENTANA FOLR1 (FOLR1-2.1) RxDx Assay. A reference panel of four expert pathologists established consensus diagnoses. Twelve pathologists independently assessed the slides, recording internal control adequacy, staining intensity (positive vs. negative), and percentage of FRα-positive tumor cells. Interobserver agreement was measured using Fleiss’ kappa and intraclass correlation coefficient (ICC). Agreement on internal control adequacy was almost perfect (κ = 0.84). Substantial agreement was observed for staining intensity (κ = 0.76), while percentage estimation showed almost perfect concordance (ICC = 0.89). Discrepancies were primarily confined to borderline cases (65–85% positivity) and tumors with intermediate staining, reflecting interpretive challenges near clinical decision thresholds. Pathologists demonstrated high reproducibility in FRα IHC assessment, particularly in estimating percentage positivity and control adequacy. These findings support the clinical utility of FRα IHC but underscore the need for standardized scoring criteria and potential integration of digital tools to enhance consistency, especially in borderline cases.

Folate Receptor Alpha in Advanced Epithelial Ovarian Cancer: Diagnostic Role and Therapeutic Implications of a Clinically Validated Biomarker

Folate receptor alpha (FRα), a glycosylphosphatidylinositol-anchored glycoprotein encoded by the FOLR1 gene, plays a crucial role in folate transport during cell growth and development. While minimally expressed in most normal adult tissues, FRα is frequently overexpressed in several epithelial malignancies, particularly in high-grade serous ovarian carcinoma. An immunohistochemical (IHC) evaluation of FRα expression using the VENTANA FOLR1 (FOLR1-2.1) RxDx Assay is now approved as a companion diagnostic for selecting patients eligible for mirvetuximab soravtansine, an FRα-targeted antibody–drug conjugate. Clinical trials such as SORAYA and MIRASOL have demonstrated significant clinical benefit in platinum-resistant epithelial ovarian cancer patients with high FRα expression (≥75% of tumor cells with moderate to strong membrane staining). This review summarizes the biological significance of FRα in ovarian cancer progression, its predictive value for targeted therapy, and the technical aspects of IHC assessment, including scoring interpretation and pre-analytical variables. We also discuss heterogeneity in FRα expression across histological subtypes and tumor sites, as well as the impact of archival versus fresh tissue. Understanding FRα expression patterns across histologic subtypes and tissue samples is critical for optimizing clinical decision-making and expanding the role of FRα-targeted therapies in gynecologic oncology.

Rethinking certainty: a retrospective study on diagnostic revisions in gynecologic pathology

Mismatch Repair Deficiency as a Predictive and Prognostic Biomarker in Endometrial Cancer: A Review on Immunohistochemistry Staining Patterns and Clinical Implications

Among the four endometrial cancer (EC) TCGA molecular groups, the MSI/hypermutated group represents an important percentage of tumors (30%), including different histotypes, and generally confers an intermediate prognosis for affected women, also providing new immunotherapeutic strategies. Immunohistochemistry for MMR proteins (MLH1, MSH2, MSH6 and PMS2) has become the optimal diagnostic MSI surrogate worldwide. This review aims to provide state-of-the-art knowledge on MMR deficiency/MSI in EC and to clarify the pathological assessment, interpretation pitfalls and reporting of MMR status.

Beyond the WHO 2020 Classification of Female Genital Tumors: Types of Endometrial Cancer: A Pathological and Molecular Focus on Challenging Rare Variants

Endometrial carcinoma is a heterogeneous group of malignancies characterized by distinct histopathological features and genetic underpinnings. The 2020 WHO classification has provided a comprehensive framework for the categorization of endometrial carcinoma. However, it has not fully addressed the spectrum of uncommon entities that are currently not recognized by the 2020 WHO and have only been described in the form of small case series and case reports. These neoplasms represent a real diagnostic challenge for pathologists; furthermore, their therapeutic management still remains controversial and information regarding tumor prognosis is very limited. This review aims to elucidate these lesser-known variants of endometrial carcinoma. We discuss the challenges of identifying these rare subtypes and the molecular alterations associated with them. Furthermore, we propose the need for expanded classification systems that include these variants to enhance clinical outcomes and research efforts. We believe that a better histological typing characterization of these entities may lead to more reproducible and accurate diagnoses and more personalized treatments. By raising awareness of these rare entities, we also hope to encourage further investigation and integration into clinical practice to improve patient care in endometrial carcinoma.

Reproductive and Oncologic Outcomes in Young Women with Stage IA and Grade 2 Endometrial Carcinoma Undergoing Fertility-Sparing Treatment: A Systematic Review

Background: Endometrial cancer (EC) is the most common gynecological malignancy in both Europe and the USA. Approximately 3–5% of cases occur in women of reproductive age. Fertility-sparing treatment (FST) options are available, but very limited evidence regarding grade 2 (G2) ECs exists in the current literature. This systematic review aimed to comprehensively evaluate reproductive and oncologic outcomes among young women diagnosed with stage IA or G2EC disease who underwent FST. Methods: A comprehensive search of the literature was carried out on the following databases: MEDLINE, EMBASE, Global Health, The Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Cochrane Methodology Register), the Health Technology Assessment Database, and Web of Science. Only original studies that reported the oncologic and reproductive outcomes of patients with stage IA and G2EC tumors who underwent FST were considered eligible for inclusion in this systematic review (CRD42023484892). Studies describing only the FST for endometrial hyperplasia or G1 EC were excluded. Results: Twenty-two papers that met the abovementioned inclusion criteria were included in the present systematic review. Preliminary analysis suggested encouraging oncologic and reproductive outcomes after FST. Conclusions: The FST approach may represent a feasible and safe option for women of childbearing age diagnosed with G2EC. Despite these promising findings, cautious interpretation is warranted due to inherent limitations, including heterogeneity in study designs and potential biases. Further research with standardized methodologies and larger sample sizes is imperative for obtaining more robust conclusions.

Atypical glandular cells and predictive features of malignancy in Pap smears: A retrospective monocentric study

Abstract Objective The introduction of cytological screening with the Papanicolau smear significantly reduced cervical cancer mortality. However, Pap smear examination can be challenging, being based on the observer ability to decode different cytological and architectural features. This study aims to evaluate the malignancy rate of AGC (atypical glandular cells) category, investigating the relationships between cytological and histological diagnosis. Methods Eighty‐nine patients, diagnosed as AGC at cytological evaluation and followed up with biopsy or surgical procedure at Policlinico Gemelli Hospital, Rome, Italy, were included in the study. The cytopathological architectural (feathering, rosette formation, overlapping, loss of polarity, papillary formation, three‐dimensional formation) and nuclear (N/C ratio, nuclear enlargement and hyperchromasia, mitoses, nuclei irregularity, evident nucleoli) features of AGC were evaluated. Statistical analyses were performed to assess cyto‐histological correlation and determine the relevance of architectural and nuclear features in the diagnosis of malignancy. Results Of the 89 AGC patients, 48 cases (53.93%) were diagnosed as AGC‐NOS and 41 (46.07%) were diagnosed as AGC‐FN, according to the Bethesda classification system. The follow‐up biopsies or surgical resections revealed malignancy in 46 patients (51.69%). The rates of malignancy for AGC‐NOS and AGC‐FN were 35.41% and 70.73% respectively. Furthermore, analysing cytopathological features, we found that both architectural and nuclear criteria were statistically significant ( p  < 0.05). Only overlapping, nuclear irregularity and increased N/C ratio were not found to be statistically significant for detecting malignancy. Conclusions Cytological diagnosis of glandular lesions remains a valid tool, when appropriate clinical correlation and expert evaluation are available.