According to the researchers, the mutation in the genes that help restore DNA damage may help to predict the prognosis of patients with bladder cancer and other related cancers.
The researchers found that patients with bladder cancer who had mutations in the RB1 gene - proteins that help repair DNA damage, do not live as long as patients without the mutation.
Monica Joshi, assistant professor of medicine, State Institute of Cancer State of Pennsylvania, said that because the researchers are trying to develop better treatments for cancer patients, it is important to find biomarkers that can help researchers to understand the differences between patients and their forecasts .
"We understand that not every patient with cancer is the same - Joshi said." We see that some patients respond to therapy while others do not. Treatments such as chemotherapy and immunotherapy, has a 100 per cent response. Therefore, we are trying to go deeper, to better understand the biological differences between patients. "
According to researchers, mutations or defects in DNA regeneration genes, like ATM and the RB1, play a role in tumor growth and how the cancer responds to treatment, and are often found in patients with bladder cancer .
Previous studies have shown a link between the mutant genes of DNA repair, and patients who respond better to certain types of chemotherapy. Joshi said that this may be because the drug used in the treatment works best in cells when they divide.
"These genes help repair DNA damage, but when these genes are mutated, they actually decrease the reduction reaction, allowing the proliferating tumor cells with defective DNA", - said Joshi. "And when these tumor cells proliferate, during this time they may be more susceptible to certain treatments, such as chemotherapy."
Joshi and other researchers want to learn more about how ATM and RB1 genes predict outcome of patients with bladder cancer and analyze information from two separate data sets.
The first set of data "detection" includes the information on 130 patients with bladder cancer from the Atlas of cancer genome, public database of genomic data and cancers. The second set of "validation" data included information on 81 patients with the disease of the urinary puzyryrya or other related cancers of the three academic medical centers.
Mutations in the ATM or the RB1 gene were found in 24 percent of patients in the data set to detect and 22.2 percent of patients in the validation data set. Patients of both data sets with these mutations tended to live so long.
Two years later, a significant difference was observed in the set of detection data, in which about 15 percent of patients with mutations were still alive compared to 45 percent of patients with no mutations. A similar (though not statistically significant) trend noted in the validation data set, where about 50% of patients with mutations were still alive, not 60% of patients without the mutation.
"It would be interesting to explore these two specific genes and see which of them can make patients worse state," - said Joshi.
The results may help researchers determine where to focus its work in the future.
"If we know that patients with this gene have a poor prognosis, we can focus our efforts to learn more about why this might happen, so we can improve treatment for these patients," - said Joshi. "After this study, we can not find the answer, but I think it helps pave the way for future development of targeted therapy of bladder cancer."