Underexpression of hepatocyte nuclear factor-1β in chromophobe renal cell carcinoma.

AIMS

Chromophobe renal cell carcinoma (ChRCC) is an uncommon malignant renal neoplasm with a generally indolent clinical behaviour. Previous studies revealed biallelic inactivation of the hepatocyte nuclear factor-1β (HNF1β) gene in several patients with ChRCC. The aims of this study were to determine HNF1β expression in renal neoplasms and the potential of HNF1β as a diagnostic marker for ChRCC.

METHODS AND RESULTS

We performed immunohistochemical staining of 79 samples taken from patients with primary renal neoplasm [19 renal oncocytomas, 18 ChRCCs, 24 clear cell renal cell carcinomas (CCRCCs), and 18 papillary renal cell carcinomas]. HNF1β was underexpressed in 16 of 18 cases of ChRCC (88.9%). By contrast, HNF1β expression was preserved in the majority of renal oncocytoma (94.7%, 18/19) and CCRCC (95.8%, 23/24) cases. The combined use of HNF1β and cytokeratin 7 (CK7) further increased the diagnostic sensitivity and specificity; the profile of HNF1β positivity and CK7 negativity was not visible in any ChRCC sample, but was common in both renal oncocytoma (94.7%, 18/19) and CCRCC (91.7%, 22/24) samples.

CONCLUSIONS

The results suggest that a lack of HNF1β expression might play an important role in the pathogenesis of ChRCC, and may serve as a good diagnostic marker for this neoplasm.