In spite of aggressive chemotherapy treatments, advanced prostate cancers have proven to be quite difficult to treat. As a heterogeneous mass of different cancerous mutations, prostate tumors often evade cellular death, and have even been known to accumulate cells capable of suppressing a body's immunological defenses. But in a new study published this week in the journal Nature, researchers have found that chemotherapy, when paired with immunotherapy, is a potent duo that has already proven successful in achieving prostate cancer remission in mouse models-now they think that the strategy may be ready to treat humans.

Known as "chemoimmunotherapy", the novel combination therapy has proven to excel where traditional immunotherapy drugs and chemotherapy alone have failed to achieve remission. And it's not just a single study that proves its efficacy-the researchers worked with three different mouse models to confirm the tests. By using immunotherapies to inhibit "Breg Cells", B Cells that often suppress the immune system in prostate cancers, and then following that with low-dose chemotherapy of oxaliplatin, the team found that the prostate tumors in all mouse models were destroyed by the mice's own immune cells.

"The presence of such [Breg Cells] in human prostate cancer calls for clinical testing of this novel therapeutic approach" coauthor of the study, Shabnam Shalapour says.

What does this mean for the future of treating prostate cancers, and difficult-to-treat tumors as well?

In addition to prostate cancer, similar immunosuppressive B cells can be detected in other human cancers" lead author of the study from UC San Diego, Michael Karin says. "This indicates that B cell-mediated immunosupression might be the reason several other cancers are also unresponsive to checkpoint inhibitors, raising the hope that chemoimmunotherapy will have broader applications for many cancer types."