Colorectal cancer (CRC) is the second most commonly diagnosed cancer in the world; after lung cancer, it is the most common cause of cancer death in the US. The lifetime risk of developing it is 1 in 20.
Advances in treatment, such as development of novel chemotherapeutic drugs and technical advances in invasive treatment for metastatic lesions, mean that most patients with stage 2 colorectal cancer have their initial cancer cured by surgery alone.
Despite successful treatment, a significant number of patients relapse and subsequently die from disease progression, due to the high risk of the cancer reappearing in another part of the body after surgery to remove the primary tumor.
Moreover, the current practice of offering chemotherapy after surgery to all patients remains controversial, according to the authors of the current research.
Researchers from the Center for Gastrointestinal Cancer Research at Baylor University Medical Center in Dallas, TX, decided to investigate prognostic biomarkers that might help identify high-risk patients.
Fast facts about colorectal cancer
- The US expects to see 93,090 new cases of colon cancer in 2015
- 39,610 cases of rectal cancer are predicted
- Deaths from colorectal cancer are expected to total 49,700.
It seems they have found a potential candidate: a gene known as snoRA42.
Ribonucleic acid (RNA) carries genetic information and is considered to be one of the building blocks of life.Recent evidence suggests that a derivative of RNA called small nucleolar RNA, or snoRNA for short, is involved in cell regulation and the development of certain types of cancer.
To see if snoRNAs would indicate a likely recurrence of disease and the chances of survival, the team assessed the expression of four different snoRNAs in 274 tissue samples.
These were taken from three separate sets of bowel cancer patients and six different types of bowel cancer cells cultured in the laboratory.
The tissue samples from the bowel cancer patients included 250 taken from the tumor itself and 24 taken from normal healthy cells lining the gut.
Higher level of snoRNAs in cancerous tissue
Analysis showed that levels of all four snoRNAs were significantly higher in cancerous than in normal cells and clearly differentiated between them; higher levels of an RNA known as snoRA42 indicated a higher risk of the return of cancer in another part of the body.
In another, smaller sample of bowel cancer patients, classified as being in the early stages of their disease (stage 2), snoRA42 identified those at high risk of recurrence and shorter survival.
Additional experimental tests showed that high levels of snoRA42 in cancer cells grown in the laboratory led to uncontrolled cell division, spread to other areas, invasion of healthy tissue, increased resistance to programmed cell death and tumor growth.
Thus, snoRA42 would appear to be a reliable biological indicator for bowel cancer patients in whom the disease is likely to return, especially those at stage 2 of the disease.
The researchers call the discovery of “enormous potential clinical significance,” and predict that snoRNAs of even more significance could yet be discovered.
“Taken together, these results underscore the potential of snoRA42 expression as a useful biomarker for selecting high-risk patients that may receive more personalized treatments in future.”
They suggest that snoRA42 could enable health services to target specific patients who would benefit from chemotherapy, and to offer intensive post-treatment surveillance to enable early detection of future recurrence in those most at risk.
Medical News Today recently reported that dried plums might help prevent recurrences of colorectal cancer.
Written by Yvette Brazier