Chromosomal deletion of 9p21 is linked to poor patient prognosis in papillary and clear cell kidney cancer.

BACKGROUND

The ongoing approval of adjuvant systemic therapy in high-risk kidney tumor will increase the demand for prognostic assessment in these tumors. 9p21 deletion has been suggested as a possible prognostic feature in clear cell kidney cancer.

MATERIAL AND METHODS

To learn more on the prognostic relevance of 9p21 deletions in clear cell and other kidney tumors, 1,809 kidney tumor specimens were analyzed by dual-labeling fluorescence in situ hybridization (FISH) with probes for 9p21 and centromere 9 in a tissue microarray format. Results were compared to histologic tumor type, pT stage, grade, and patient outcome.

RESULTS

A total of 1,341 (74%) of tumor samples had interpretable FISH results. 9p21 deletion was found in 4.4% of 894 clear cell, 5.1% of 197 papillary, and 4.2% of 71 chromophobe carcinomas. 9p21 deletions were not found in 112 oncocytomas and in 21 clear cell tubulo-papillary cancers. In clear cell carcinomas, 9p deletions were associated with advanced stage (P = 0.009) and nodal metastasis (P = 0.0067), but not with ISUP grade (P = 0.1039) and distant metastasis (P = 0.4809). Also, in papillary carcinomas, 9p deletions were associated with advanced stage (P = 0.0008) and nodal metastasis (P = 0.0202) but not with ISUP grade (0.0904) and distant metastasis (P = 0.2022). Follow-up data were available for 789 clear cell and 177 papillary cancers. In both tumor entities, 9p21 deletions were associated with shortened overall survival, tumor-specific death, and progression-free survival in univariate analysis (P < 0.02 each). In a multivariate analysis, 9p21 deletion was an independent predictor of early tumor recurrence (P = 0.04).

CONCLUSION

9p21 deletions, 9p21 deletions identify a small subset of aggressive renal carcinomas. 9p deletion assessment may be clinically useful to identify high-risk renal cell carcinomas.