RT Journal Article
SR Electronic
T1 Colorectal carcinoma from Saudi Arabia. Analysis of MLH-1, MSH-2 and p53 genes by immunohistochemistry and tissue microarray analysis.
JF Saudi Medical Journal
JO Saudi Med J
FD Prince Sultan Military Medical City
SP 323
OP 328
VO 27
IS 3
A1 Khawla S. Al-Kuraya
A1 Prashant P. Bavi
A1 Adnan A. Ezzat
A1 Fouad A. Al-Dayel
A1 Shahab Uddin
A1 Valerie L. Atizado
A1 Naif A. Al-Jomah
A1 Samir S. Amr
A1 Salwa S. Sheikh
A1 Guido Sauter
A1 Ronald Simon
YR 2006
UL http://smj.org.sa/content/27/3/323.abstract
AB OBJECTIVE: To document the incidence and role of p53 and DNA mismatch repair proteins in colorectal carcinomas, and to evaluate the relative frequency of major molecular pathways in colorectal cancers from Saudi Arabia.METHODS: We collected the formalin fixed, paraffin embedded tissues from 154 colorectal tumors (83 patients from King Faisal Specialist Hospital and Research Centre and 71 from Saudi Aramco Dhahran Health Centre) between January 1989 and December 2003. We analyzed the p53 and mismatch repair gene expression (hMSH-2, hMLH-1) by immunohistochemistry in tissue microarray format.RESULTS: Expression loss of at least one mismatch repair gene was found in 33.8% of cases and significantly associated with the right-sided tumor location (p=0.0047). The p53 positivity was observed in 57.5% of tumors, and was inversely linked to expression loss of mismatch repair genes (p=0.0102).CONCLUSION: The strong confirmation of the previously established associations between tumor phenotype, and mismatch repair gene alteration provided strong evidence for the validity of our experimental approach. Together with the higher incidence of right sided location in Saudi (46.6%) than in Western colon cancers (34.9%), the observed high prevalence of mismatch gene expression loss in Saudi tumors argues for a higher importance of microsatellite instability in this population. If confirmed, it will be interesting to see whether an increased level of familial or sporadic microsatellite instability cases is causing this variation.