Immunohistochemical and molecular genetic profiling of acquired cystic disease‐associated renal cell carcinoma

AIMS: Acquired cystic disease-associated renal cell carcinoma (ACD-associated RCC) is a unique neoplasm that specifically develops in the background of acquired cystic disease of the kidney. The aim was to analyse nine ACD-associated RCCs from three patients to determine their immunohistochemical and molecular characteristics using immunohistochemistry, comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH). METHODS AND RESULTS: ACD-associated RCC preferentially expressed proximal nephron phenotype (CD10+ /RCC marker+/alpha-methylacyl-CoA racemase+ /glutathione S-transferase-alpha+ /BerEP4+ /cytokeratin 7- /E-cadherin- /high-molecular-weight cytokeratin- /MOC31-). CGH combined with FISH demonstrated non-random chromosomal gains clustering on chromosomes 3 (8/9), 7 (6/9), 16 (7/9), 17 (4/9) and Y (5/9). Chromosomal losses were uncommon. The chromosomal aberrations in all multifocal tumours were not identical for the same kidney or for the same patient, indicating a 'field effect' that induces multiple independent clones. CONCLUSIONS: Although the genetic profiles of ACD-associated RCC showed some similarity to those of papillary RCC, ACD-associated RCC distinctly revealed frequent gains on chromosomes 3 and Y. ACD-associated RCC is characterized not only by its particular clinical setting and histology, but also by its unique immunohistochemical and molecular genetic profiles.