REVOLUTIONARY information has been brought forward by scientists, who have identified two subtypes of metastatic prostate cancer that responding differently to treatment. This progression holds exciting potential for personalising treatment and opening-up the possibility of providing therapy best suited to an individual based on their disease profile. Researchers have divided metastatic prostate tumours into two subgroups based on genetic signatures, known as luminal and basal.
Clear disparities discovered in this research were that the luminal group of tumours responded better to testosterone-blocking treatment, and basal tumours included the particularly aggressive form of small cell neuroendocrine prostate cancer. These findings came as a result of the computational methods employed to compare the patterns of gene expression in tumour biopsies. Building on a previous study, which looked into the similarities between breast and localised prostate cancer, this research was more complex due to the difficulties taking biopsies as well as analysing metastatic cancer and small tumours spreading to multiple different parts of the body from the prostate. Shuang Zhao, University of Wisconsin, USA, and lead researcher of this project, described their methodology: “We pooled all of the data together and assembled the largest metastatic prostate cancer cohort to date,” culminating to a total of 634 samples. The team were able to separate the two subtypes based on the activity of a group of 50 genes determining basal-or-luminal nature.
Follow-up questions from the information gathered include how the groupings differ in patient survival and response to treatment. Before drawing strong conclusions or making decisions based on any new diagnostic-based treatment selection, the researchers recognised that further clinical trials are required. Despite discovering two distinctive groups, the researchers identified that tumours fell on a spectrum: one side of this was hormone-treatment-resistant small cell neuroendocrine prostate cancers (appearing the most basal), and the other extreme were less aggressive tumours sensitive to hormone therapy (luminal subtype). The critical finding was that tumours fell between these poles. Future research will clarify the best treatment options for this middle-ground. Other action warranted by the current investigation includes investigation into developing blood tests to determine which subgroup metastatic prostate cancers fall into; biomarker tests such as this will dramatically increase the feasibility of clinical trials testing the usefulness of subtyping metastatic tumours.