AACR Logo Patients with a particular variant now seem to have better early-stage cancer prognosis. A latest research claims that the Jekyll-Hyde microRNA binding variant associated with poor outcome in advanced colorectal cancer anticipates improved diagnoses in early stages of cancer. Advancement in cancer identification among patients with the variant is possible only in the early stages.

The binding site supposedly responds to a molecule of the lethal-7 (let-7) family of microRNAs, which were previously linked to regulate the KRAS gene. If unregulated or mutated the gene can possibly trigger the onset of colorectal cancers. Experts assume that the ‘G’ variant at this site results in poorly controlled KRAS as it disallows correct binding of let-7 to the gene, further paving way for heightened KRAS expression. The G variant has also been correlated to an increased risk of lung cancer in moderate smokers, elevated threats of ovarian cancer, decreased survival among oral cancers patients and reduced survival in late-stage colorectal cancer independent of KRAS mutations.

At the time of the investigation, Kim M. Smits, Ph.D., lead researcher, a molecular biologist and epidemiologist in the GROW-School for Oncology and Developmental Biology at Maastricht University Medical Center, in the Netherlands and colleagues analyzed the effect of the G variant on early-stage colorectal cancer as compared to the more common ‘wild type’ T variant. Tissue from 409 early-stage colorectal cancer patients was examined by the investigators. All the participants were a part of the Netherlands Cohort Study from 1989 to 1994.

With a median survival of 7.6 years, G variant probably had a 54 percent improved survival than patients with T variant. Betterment in survival appeared while considering KRAS mutations. No death was registered among patients with a KRAS mutation and the T variant. Survival advantage was probably reversed in later stages of the cancer. Researchers presume that KRAS is controlled by another unidentified pathway in patients with the G variant. Hence such patients may develop better prognosis on activating KRAS mutation.

The research was presented at the American Association for Cancer Research special conference on Colorectal Cancer: Biology to Therapy held on October 27-30, 2010.