Royce, S.G., Alsop, K., Haydon, A., Mead, L., Smith, L.D., Tesoriero, A.A., Giles, G.G., Jenkins, M.A., Hopper, J.L., and Southey, M.C. (2010) The role of SMAD4 in early-onset colorectal cancer. Colorectal Disease, 12 (3). pp. 213-219.

PDF (Published Version) - Published Version Restricted to Repository staff only

20

Abstract

Objective: Chromosomal loss within the region of 18q and loss of SMAD4 expression have been reported to be frequent somatic events during colorectal cancer tumour progression; however, their associations with age at onset have not been widely studied.

Method: We analysed 109 tumours from a population-based case-family study based on colorectal cancers diagnosed before the age of 45 years. These patients with early-onset colorectal cancer had been previously screened for germ-line mismatch repair gene mutations, microsatellite instability (that included the mononucleotide repeat in TGFβRII) and somatic k-ras mutations. We measured SMAD4 protein expression using immunohistochemistry and SMAD4 copy number using quantitative real-time PCR.

Results: Loss of SMAD4 protein expression was observed in 27/109 (25%) of cancers tested and was more commonly observed in rectal tumours (15/41, 36%) when compared with tumours arising in the colon (11/66, 17%) (P = 0.04). There was no association between SMAD4 protein expression and TGFβR11 mutation status, SMAD4 copy number, family history, MSI status, tumour stage or grade.

Conclusion: Loss of SMAD4 expression is a common feature of early-onset colorectal tumours as it is in colorectal cancers diagnosed in other age-groups. Taken together, the molecular pathways (genetic and epigenetic) now known to be involved in early-onset colorectal cancer only explain a small proportion of the disease and require further exploration.

Actions (Repository Staff Only)

Item Control Page