The presence of molecular tags on a gene may be a new marker for predicting a prostate cancer’s aggressiveness and likelihood of recurrence, and help to identify those patients who would benefit from interventions, and spare those in need of continued monitoring from unnecessary treatment.
The gene in question, called PITX2, has previously been explored in breast and lung cancer, where studies have shown that its extensive methylation is linked to disease progression. Methylation — the attachment of chemical methyl groups to the DNA — is a cellular method of silencing a gene.
Methylation of PITX2 gene has also been explored in prostate cancer, but earlier studies all looked at cancer recurrence after surgical removal of the prostate. This time, researchers looked at tissue biopsies gathered before surgery to identify the marker — meaning a simple biopsy might be sufficient for patients as well.
To explore if the molecular labeling of the gene could serve as a biomarker for aggressive cancer in these patients, researchers compared a variety of tissue samples: 24 tumor samples, 24 samples of normal prostate tissue adjacent to cancerous tissue, and 22 biopsy samples from people with benign prostatic hyperplasia (BPH), or noncancerous prostate enlargement.
Levels of PITX2 methylation were substantially higher in cancerous tissue, compared to normal tissue or that obtained from BPH patients, they reported.
Next, the team confirmed previous data, showing that PITX2 methylation in tissue from biopsies during surgical prostate removal correlated to biochemical recurrence. This term denotes two consecutive increases in prostate specific antigen (PSA) levels above a threshold value.
The researchers then returned to study needle core biopsies in another set of 32 prostate cancer patients and in 31 patients with BPH. In total, they collected 753 biopsies from patients, and showed that methylation levels were linked to the cancer’s severity.
Physicians often differ on how to treat prostate cancer, and a recent study demonstrated that radical treatment did not provide patients with any survival benefits but was linked to plenty of side effects.
In light of such findings, it becomes even more crucial to carefully identify patients at higher risk for cancer recurrence and likely in need of active treatment — whether pharmacological, radiotherapeutic, or surgical.
“This study not only confirms the prognostic value of PITX2 methylation in prostate cancer, but it also demonstrates its applicability to prostate biopsies,” Glen Kristiansen, MD, of the Institute of Pathology at the University Hospital Bonn in Germany, and the study’s senior author, said in a news release.
“This enables us to plan further studies that may finally translate this biomarker into clinical practice with the aim of further individualizing treatment strategies,” he added.