KIAA1096,a Gene on Chromosome 1q,is Amplified and Overexpressed in Bladder Cancer

Abstract

Chromosomal gain on 1q23-24 is a cytogenetic finding found in approximately 30% of bladder tumors. Currently, no defined or candidate tumor-associated genes from this region have been identified. The objective of this study was to identify and quantitate the expression of putative cancer genes located at this chromosome locus in normal urothelium, superficial, and muscle invasive bladder tumors. We examined both normal and bladder cancer tissue specimens (N = 40-80 RNA, DNA, and protein) by semiquantitative RT/PCR, genomic PCR, and by Western blotting. The KIAA1096 gene is located at 1q23-24 with no overexpression or amplification in normal urothelium, but was significantly upregulated in 30% of tumors (P = 0.0001). There was a trend towards increased expression in invasive compared to superficial lesions(P = 0.06). A significant increase in gene copy was also found in a 38% of TCC of the bladder compared to normal bladder mucosa or peripheral blood lymphocytes. Immunohistochemistry (IHC) demonstrated KIAA1096 expression in nonmalignant bladder mucosa tissue but apparent upregulation in invasive transitional cell carcinoma. Two other genes, CH1 and RGS5, which are situated in the same region of chromosome 1q, demonstrated disparate patterns of expression. In summary, KIAA1096 is a gene situated at 1q23-24, which demonstrated a pattern of RNA and DNA expression consistent with the 38% expression of cytogenetic amplification noted on previous studies. This gene may, therefore, be a putative marker for this cytogenetic phenomenon and provide an opportunity to evaluate the clinical significance of previous cytogenetic findings.