Chromosomal instability detected by interphase fluorescence in situ hybridization and its relation to p53 alteration in prostate carcinoma in Saudi patients

OBJECTIVE: Chromosomal instability (CIN) is a feature of human neoplasm. The p53 mutation has been shown to be associated with CIN in many human dysplastic and neoplastic lesions. The objective of this study was to examine CIN and p53 mutations in prostate carcinoma (Pca) resected from Saudi patients.

METHODS: Testing of p53 alteration using immunohistochemistry was performed on 28 archived prostatic carcinoma specimens containing Pca foci from Saudi patients seen at King Abdul-Aziz University Hospital, Jeddah, Kingdom of Saudi Arabia. Chromosomal instability was evaluated in the same tissues by interphase in situ hybridization (IFISH) using centromere probes for chromosome 7 and 8. Immunohistochemistry and IFISH were performed at Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada in 2001.

RESULTS: The p53 immunoreactivity was found in 29% in Pca and 0% in benign epithelium. Interphase in situ hybridization revealed numerical chromosomal alterations in keeping with CIN in 63% of p53 positive and 20% p53 negative Pca. No evidence of CIN was seen in non-neoplastic epithelium.

CONCLUSION: We concluded that CIN as determined by IFISH is present in Pca from Saudi patients similarly to those reported in western countries. The p53 mutation occurs relatively infrequently in Pca and is associated with the presence of CIN at least in a subset of Pca.