Microsatellite alteration and immunohistochemical expression profile of chromosome 9p21 in patients with sporadic renal cell carcinoma following surgical resection.

BACKGROUND: Long-term prognostic significance of loss of heterozygosity on chromosome 9p21 for localized renal cell carcinoma following surgery remains unreported. The study assessed the frequency of deletions of different loci of chromosome 9p along with immunohistochemical profile of proteins in surgically resected renal cancer tissue and correlated this with long-term outcomes. METHODS: DNA was extracted from renal tumours and corresponding normal kidney tissues in prospectively collected samples of 108 patients who underwent surgical resection for clinically localized disease between January 2001 and December 2005, providing a minimum of 9 years follow-up for each participant. After checking quality of DNA, amplified by PCR, loss of heterozygosity (LOH) on chromosome 9p was assessed using 6 microsatellite markers in 77 clear cell carcinoma. Only 5 of the markers showed LOH (D9S1814, D9S916, D9S974, D9S942, and D9S171). Protein expression of p15(INK4b), p16(INK4a), p14(ARF), CAIX, and adipose related protein (ADFP) were demonstrated by immunostaining in normal and cancer tissues. Loss of heterozygosity for microsatellite analysis was correlated with tumour characteristics, recurrence free, cancer specific, and overall survival, including significance of immunohistochemical profile of protein expressions. RESULTS: The main deletion was found at loci telomeric to CDKN2A region at D9S916. There was a significant correlation between frequency of LOH stage (p = 0.005) and metastases (p = 0.006) suggesting a higher LOH for advanced and aggressive renal cell carcinoma. Most commonly observed LOH in the 3 markers: D9S916, D9S974, and D9S942 were associated with poor survival, and were statistically significant on multivariate analysis. Immunohistochemical expression of p14, p15, and p16 proteins were either low or absent in cancer tissue compared to normal. CONCLUSIONS: Loss of heterozygosity of p921 chromosome is associated with aggressive tumours, and predicts cancer specific or recurrence free survival on long-term follow-up. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12885-016-2514-8) contains supplementary material, which is available to authorized users

Deletions of chromosome 8p and loss of sFRP1 expression are progression markers of papillary bladder cancer

Many molecular alterations are known to occur in urothelial carcinoma of the bladder, but their significance for tumor progression is poorly understood. Deletions of chromosome 8p are frequently found in several tumor types and are often associated with progressive disease. In all, 99 bladder tumors were screened for deletions at 8p using loss of heterozygosity (LOH) and multicolor fluorescence in situ hybridization FISH analyses. Allelic loss on chromosome 8p in at least one marker was found in 25/99 (25%) tumors. There was a significant correlation of 8p deletions with invasive tumor growth and a highly significant association with papillary growth pattern in patients with invasive disease. cDNA array analyses revealed that secreted Frizzled-related protein 1 (sFRP1), an antagonist of Frizzled receptors and Wnt pathway activation on chromosome 8p12-11.1, is frequently downregulated in bladder cancer. To investigate sFRP1 as a candidate for a putative progression-related gene on 8p, urothelial cell lines and primary urothelial carcinomas were screened for sFRP1 expression using quantitative real-time PCR, Northern blot, immunofluorescence and immunohistochemistry (IHC). Of the investigated bladder cancers, 38% showed loss of sFRP1 expression by quantitative RT-PCR. Evaluation of the protein expression by IHC using tissue microarrays containing 776 bladder cancers revealed loss or strong reduction of sFRP1 expression in 66% of cases. SFRP1 loss was associated with higher tumor stage and grade and shorter overall survival. In addition, loss of sFRP1 was an independent indicator of poor survival in patients with papillary but not with muscle invasive bladder cancer. There were neither mutations in the coding region of sFRP1 nor homozygous deletions at 8p12-11.21. However, promoter methylation was detected using methylation-specific PCR in 29% of cases. In conclusion, we could show a close correlation of chromosome 8p deletions and progression of papillary bladder tumors. The sFRP1 gene on chromosome 8p12-11.1 could be a candidate gene for the predicted, progression-related tumor suppressor gene in bladder cancer and could contribute to urothelial carcinogenesis