Deletions of chromosomes 3p and 14q molecularly subclassify clear cell renal cell carcinoma

The short arm of chromosome 3 (3p) harbors the von Hippel-Lindau (VHL) tumor suppressor gene, and the long arm of chromosome 14 (14q) harbors the hypoxia-inducible factor 1α (HIF-1α) gene. The objective of this study was to evaluate the significance of 3p loss (loss VHL gene) and 14q loss (loss HIF-1α gene) in clear cell renal cell carcinoma (ccRCC).

In total, 288 ccRCC tumors underwent a prospective cytogenetic analysis for alterations in chromosomes 3p and 14q. Tumors were assigned to 1 of 4 possible chromosomal alterations: VHL +3p/+14q (VHL wild type [VHL-WT]), VHL +3p/-14q (VHL-WT plus HIF2α [WT/H2]), -3p/+14q (HIF1α and HIF2α [H1H2]), and -3p/-14q (HIF2α [H2]).

Among patients who had loss of 3p, tumors with -3p/-14q (H2) alterations were larger (P = .002), had higher grade (P = .002) and stage (P = .001), and more often were metastatic (P = .029) than tumors that retained 14q (H1H2). All patients who had tumors with -3p/-14q (H2) had worse cancer-specific survival (P = .014), and patients who had localized disease (P = .012) and primary T1 (pT1) tumors (P = .008) had worse recurrence-free survival. In patients who had pT1 tumors, combined 3p/14q loss was an independent predictor of recurrence-free survival (hazard ratio, 11.19; 95% confidence interval, 1.91-65.63) and cancer-specific survival (hazard ratio, 15.93; 95% confidence interval, 3.09-82.16). The current investigation was limited by its retrospective design, single-center experience, and a lack of confirmatory protein analyses.

Loss of chromosome 3p (the VHL gene) was associated with improved survival in patients with ccRCC, whereas loss of chromosome 14q (the HIF-1α gene) was associated with worse outcomes. The results of the current study support the hypothesis that HIF-1α functions as an important tumor suppressor gene in ccRCC.