As mentioned in the video update: 

For those of you interested in how infection and mantle cell lymphoma are connected please read here:

The problem is that MCL can grow back from one mutated cell. If chemotherapy removes a very large percent of the cells, but leaves a few behind then the cells may grow back over time if your body’s immune system is unable to keep those cells in check. As one gets older, the immune system may weaken and thus the ability to keep MCL cells from duplicating can happen. That’s the reason that the oncologists try to give very strong treatments up front and use consolidation therapy (stem cell transplant and/or maintenance treatments) to deepen the the response to the initial therapy.

Different types of visualization methods are used to determine if you have a received a complete response to the treatment, such as PET/CT scans or CT scans. But these imaging methods can only measure down to about one cell in 10,000. Some of the molecular tests like Clonoseq can only measure down to one cell in a million. But there are trillions of cells in the body, so even using multiple Clonoseq test results, doctors are unable to verify that all MCL cells are gone after treatment.

So why are some lymphomas more curable than others? The very aggressive diseases have many more of the diseased cells replicating at any time, and chemotherapy targets the rapidly changing cells, and thus can wipe out a greater majority of the bad cells (and some of your healthy cells that are also replicating). If your disease does not have all the cells replicating at one time, then chemotherapy is less effective. Other non-chemotherapy approaches, like BTK inhibitors, work differently than chemotherapy but can develop mutations over time that decrease their effectiveness. That’s why for now, the goal of some oncologists is to keep the MCL at bay like a chronic disease.