A study presented at a symposium recently shows how differences in colorectal cancer between younger and older patients may be distinguished genetically – a finding that could pave the way for better treatments for younger patients.
The study was presented earlier this month at the 2016 Gastrointestinal Cancers Symposium in San Francisco, CA.
It shows “distinct genetic differences” in tumors sampled from younger and older colorectal cancer patients, says investigator Christopher Lieu, assistant professor of medical oncology at the University of Colorado School of Medicine, located at the Anschutz Medical Campus in Aurora.
While the overall rate of colorectal cancer in the US is falling, it masks a rising rate in the 10% or so of patients who are aged 50 and under, note the researchers.
Prof. Lieu and colleagues note recent data also suggests that younger patients are at higher risk of disease progression and death from the cancer.
The purpose of the new study is to look more closely at any genetic causes that might explain why colorectal cancer appears to be more aggressive when it hits younger people.
Prof. Lieu and colleagues compared 9 tumors from patients of median age 31 with 9 tumors from patients of median age 73. Using a high throughput sequencer, they extracted “45 million reads” from each sampled tumor and looked for “enriched genes,” that is, genes that are over-represented.
The researchers note that they found, “in total 77 genes were […] enriched in younger patients compared with older patients and 23 genes were enriched in older patients compared with young patients.”
Many of the enriched genes of the younger patients’ tumors are known to be important for signaling pathways involved with cell proliferation commonly associated with cancer: for instance ERBB2, NOTCH3 and CAV1.
In contrast, in the older patients’ tumors, they found the enriched genes were mostly involved in cell differentiation as opposed to cell proliferation – for instance CDX2, HMGB3 and EPHB2. Cell differentiation is where stem-like immature cells mature in tissue-specific cell types.
The researchers point out FDA-approved therapies that target one of the genes that came up in the younger patient sample – ERBB2 (Her2/neu) – are already available.
Should the findings be confirmed with larger groups of people, then the researchers plan to explore setting up trials of drugs that target the tumor drivers. They are partway there, in that they already have a collection of tumor samples grown from the tissues of young colorectal cancer patients – which are needed for preclinical genetic and drug testing.
Prof. Lieu concludes:
“If I were to shoot for the stars, I would say that our end goal is to be able to offer better treatments for this population of young colorectal cancer patients that seems to be at higher risk from the disease.”
Meanwhile, Medical News Today recently learned about the discovery of a biomarker that may predict which patients with stage 2 cancer of the colon may benefit from post-surgery chemotherapy.