[Morphological and immunohistochemical characteristics of the molecular subtypes of urothelial carcinomas].

Unlabelled: The molecular subtypes of urothelial carcinoma in each classification scheme have characteristic immunohistochemical features. At the same time, the results of conducted studies often demonstrate a discrepancy between the genomic profile of urothelial carcinoma and its immunophenotype, which complicates the immunohistochemical verification of the molecular subtypes of these tumors.

Objective: To compare the morphological and immunophenotypic characteristics of the molecular subtypes of urothelial carcinoma.

Material And Methods: Surgical specimens from 196 patients diagnosed with urothelial carcinoma of the renal pelvis and bladder were investigated. Paraffin-embedded sections were immunohistochemically examined using the standard protocol. Antibodies against CK5/6, CK17, Rb1 (Dako), CK14, CK18, CK20, Cyclin D1, Cyclin E1, Cyclin A, Cyclin B, Chromogranin, E-Cadherin, P-Cadherin, p16, Uroplakin II, TUBB2B, Vimentin, ZEB-2 ('Novocastra'), CD44, GATA-3, and Uroplakin III ('Cell Marque') were used.

Results: Out of 68 (35%) superficial papillary urothelial carcinomas, 24 (12%) tumors constituted Molecular Class I and 12 (6%) and 32 (16%) ones did Molecular Classes II and III, respectively. Of the 128 (65%) muscle-invasive urothelial carcinomas, 57 (29%) tumors were referred to as the luminal-papillary molecular subtype, and 24 (12%) and 14 (7%) were as the luminal-infiltrated and luminal molecular subtypes, respectively. The basal squamous molecular subtype was verified in 31 (16%) neoplasms and the neuronal phenotype was detected in 2 (1%) cases.

Conclusion: Most pT tissues correspond to Molecular Class II. In the muscle-invasive urothelial carcinoma group, the neoplasms with a luminal phenotype predominate over the tumors with basal and neuronal phenotypes.