Background: T-cell receptor gamma (TCR-gamma) is involved in maintaining host cell integrity and homeostasis of the human immune system. We hypothesize that polymorphism of the TCR-gamma complex may be involved in the pathogenesis of colorectal cancer.
Methods: The microsatellite markers D7S1818 and D7S2206 located within the TCR-gamma antigen locus on chromosome 7p were amplified by polymerase chain reaction, and genotypes were determined for 22 patients with early onset of colorectal cancer (<60 years old) and for 38 population-based control subjects.
Results: Genotype BC of D7S1818 (P = .049) and haplotype AC of D7S1818/D7S2206 (P < or = .003) were associated with colorectal cancer as compared with the control population (extended Fisher's exact test).
Conclusions: This study identifies a novel genetic and clinical association between TCR-gamma and early-onset colorectal cancer. Many young patients do not fulfill the criteria for hereditary colorectal cancer syndromes and are therefore not identified by established screening programs. Markers such as D7S1818 and D7S2206 may become useful in the identification of patients at risk of developing colorectal cancer and permit earlier therapeutic intervention.