Chromosome 14q loss defines a molecular subtype of clear-cell renal cell carcinoma associated with poor prognosis.

Abstract

Loss of chromosome 14 has been associated with poor outcomes in clear-cell renal cell carcinoma. Expression of HIFα isoforms has been linked to distinct molecular phenotypes of clear-cell renal cell carcinoma. We hypothesized that chromosome 14 loss could lead to a decrease in HIF1α levels, as its gene (HIF1A) resides in this chromosome. We analyzed 112 archival clear-cell renal cell carcinoma tumor specimens with 250K SNP microarrays. We also evaluated expression of HIFα isoforms by qPCR and immunohistochemistry in a subset of 30 patients. Loss of chromosome 14q was associated with high stage (III-IV, P=0.001), high risk for recurrence (P=0.002, RR 2.78 (1.506-5.153)) and with decreased overall survival (P=0.030) in non-metastatic clear-cell renal cell carcinoma. HIF1α mRNA and protein expression was reduced in specimens with loss of 14q (P=0.014) whereas HIF2α was not. Gain of 8q was associated with decreased overall survival (P<0.0001). Our studies confirm an association between 14q loss and clinical outcome in non-metastatic clear-cell renal cell carcinoma patients and that 8q gain is a candidate prognostic marker for decreased overall survival and appears to further decrease survival in patients with 14q loss. We have also identified that differential expression of HIF1α is associated with 14q loss. Further exploration of 8q gain, 14q loss, MYC, HIF1A and EPAS1 (HIF2α) as molecular markers of tumor behavior and prognosis could aid in personalizing medicine for patients with clear-cell renal cell carcinoma.