Dae Hyun Song

Differential Expression of S100A8 in Tumor and Immune Compartments of Endometrial Carcinoma and Its Clinical Relevance

Background and Objectives: S100A8 regulates inflammatory responses and immune cell activation and is overexpressed in several solid tumors. However, its clinicopathological significance in endometrial carcinoma (EC) remains unclear. This study aimed to evaluate the expression patterns of S100A8 in both tumor and immune cells of EC and examine its association with clinicopathological features. Materials and Methods: Fifty-two formalin-fixed, paraffin-embedded EC specimens were analyzed using tissue microarray-based immunohistochemistry. S100A8 expression was assessed in tumor and immune cells. The tumor proportion score (TPS), tumor staining intensity (TI), and immune proportion score (IPS) were dichotomized into low and high categories (TPS/IPS: ≤30% vs. ≥31%; TI: 0–1+ vs. 2–3+). Correlations with clinicopathological parameters were examined using the chi-square and Fisher’s exact tests. Results: A low TPS, high TI, and high IPS were observed in 51.9%, 63.5%, and 57.7% of patients, respectively. TPS and TI showed no significant correlation with clinicopathological variables, including age, tumor size, invasion depth, histologic grade, T stage, and N stage (all p > 0.05). By contrast, IPS was significantly associated with patients’ age (p = 0.044) and histologic grade (p = 0.012), with older patients and those with higher-grade tumors demonstrating a higher IPS. A positive correlation was observed between TPS and IPS (p = 0.044), whereas TI did not correlate with IPS (p = 0.253). Conclusions: S100A8 expression in immune cells, but not in tumor cells, is associated with age and tumor grade in EC. Therefore, immune-related S100A8 expression may serve as a biomarker of the tumor immune microenvironment, warranting further investigation into its prognostic and therapeutic implications.

Expression of Core Hippo Pathway Proteins in Cervical Cancer and Their Association with Clinicopathologic Parameters

Background: The Hippo signaling pathway, a highly conserved regulatory cascade, regulates tissue homeostasis, organ size, and tumor suppression. Dysregulation of this pathway contributes to oncogenesis in various human malignancies; however, its clinicopathologic relevance in cervical cancer has not been completely elucidated. Therefore, this study aimed to investigate the expression patterns of key Hippo pathway proteins and analyze their associations with tumor behavior and clinicopathologic features in cervical carcinoma. Materials and Methods: Ninety-nine cervical cancer specimens obtained from hysterectomies performed at Gyeongsang National University Hospital (2012–2019) were retrospectively analyzed. Immunohistochemical staining for Yes-associated protein (YAP), phosphorylated YAP (p-YAP), mammalian sterile-20-like kinase-1 (MST1), and large tumor suppressor kinase-1 (LATS1) was performed on tissue microarrays. Chi-square or Fisher’s exact tests and logistic regression were employed for assessing associations between marker expression and clinicopathologic variables. Functional validation was conducted via small interfering RNA-mediated YAP knockdown in Caski cervical cancer cells, with reverse transcription-polymerase chain reaction, Western blotting, and wound-healing assays assessing YAP suppression and cell migration. Results: YAP and p-YAP were expressed in 71.8% and 62.6% of tumors, respectively; MST1 in 82.8%; and LATS1 in 22.2%. YAP and p-YAP overexpression was correlated with larger tumor size (p = 0.013 and p = 0.011) and higher International Federation of Gynecology and Obstetrics stage (p = 0.007 and p < 0.001). YAP and p-YAP expression was positively correlated (odds ratio, 4.34; 95% confidence interval, 1.70–11.61). MST1 or LATS1 expression demonstrated no significant associations. In vitro, YAP silencing decreased mRNA and protein expression levels and significantly impaired cell migration, supporting its role in tumor aggressiveness. Conclusions: YAP and p-YAP overexpression are associated with advanced stage and larger tumor size in cervical cancer, indicating Hippo pathway dysregulation. YAP functional suppression attenuated migratory capacity, highlighting YAP as a promising prognostic biomarker and therapeutic target.