International Journal of Molecular and Cellular Medicine (IJMCM)

Ectopic expression of Placenta-specific 1 (PLAC1), a Cancer/Testis Antigen (CTA), was reported in various tumors, but its clinical relevance and prognostic value in bladder urothelial carcinoma (UC) remain unclear. This study evaluated PLAC1 expression in the membrane, cytoplasm, and nucleus of tumor cells and its clinicopathological significance in bladder UC patients. We analyzed 177 bladder UC samples to assess nuclear, cytoplasmic, and membranous PLAC1 expression by immunohistochemistry (IHC) on tissue microarrays (TMAs) and examined its associations with clinicopathological characteristics and prognosis. Higher cytoplasmic expression of PLAC1 was associated with increased histological grade (P< 0.001), advanced pathological primary tumor (pT) staging (P= 0.038), lamina propria involvement (P= 0.013), and lamina propria/muscularis (L/M) involvement (P= 0.038). A significant association was identified between the increased nuclear expression of PLAC1 and tumor size (P= 0.036) and higher histological grades (intensity of staining, P= 0.045). PLAC1 expression was not significantly associated with disease-specific survival (DSS) or progression-free survival (PFS) in bladder UC patients.
Cytoplasmic PLAC1 expression significantly correlates with higher tumor grade and advanced stage in bladder cancer, suggesting its potential as an exploratory biomarker. The association between PLAC1 expression and tumor invasiveness warrants further functional and prospective studies to clarify its biological significance.