SNPs are single-letter variations within the four-letter DNA alphabet. They are increasingly recognized as having an important role in disease progression. Often prostate cancer is slow growing. Men with the disease often die of other causes before the malignancy turns deadly. But prostate cancer patients are usually treated with either surgery or radiation because there is no reliable way to determine if an individual patient’s prostate cancer is slow growing or aggressive.
In the newly published study, researchers analyzed DNA samples from 1,309 Seattle-based prostate cancer patients, looking for gene variants suspected of being involved in tumor progression. The analysis of 156 candidate genes identified 22 SNPs linked to prostate cancer-specific death.
In a separate analysis, the researchers examined these variants in stored DNA samples from close to 2,900 prostate cancer patients in Sweden who had been followed for an average of six and a half years. Five of the 22 SNPs emerged as being significantly associated with death from prostate cancer in this larger group of patients.
The variants included:
- LEPR, a leptin receptor gene involved in tissue growth, inflammation, the development of blood vessels and bone density. The bone density association may explain why prostate cancers often spread to the bone before spreading to other organs, the researchers suggested.
- RNASEL, a gene associated with programmed cell death, inflammation, and the ability of cells to multiply rapidly.
- Interleukin 4, which is associated with tumor growth, blood vessel development, and cancer cell migration.
- Cytochrome 1, which is a gene involved in circadian rhythms, which could affect testosterone levels.
- ARVCF, a gene that is involved in cell communication, which has previously been linked to cancer progression.
Patients who carried four or all five of the SNPs had a 50% higher risk of dying from their cancer than patients who had two or fewer of the SNP variants. The next step is to confirm the findings in different groups of patients and to determine if these five SNPs or any of the other identified gene variants are useful for predicting death from prostate cancer.
Finding better tests to identify patients who will benefit from therapy is an important goal for reducing the harms from prostate cancer overtreatment, along with finding more effective targeted therapies that do not have life-altering side effects. Since Black men have a higher chance of dying from their prostate cancer, they should start prostate cancer screening with yearly PSA tests
and physical exams at age 40, and even earlier if a strong family
history of prostate cancer exists.
For more information on prostate cancer, prevention, and treatment, read: African American & Prostate Cancer