Sci-Fi?

... and then the cancerous tumors, each of similar origin began to enter the blood stream of each patient, and reached their respective brains.

In the first patient, the cancerous cells intruded into the brain. The body sensed the intruders and began to attack. The patient fought the cancer hard. The cancer never truly harmed the man; however two effects lead to his demise. First, the stress of inflammation in response to the tumor cells created stressors dramatically harming his well being. Secondly, an auto-immune response formulated. His hard fight began to fight his own healthy cells. It was a painful death.

The second patient reacted to the cancer in a very different manner. It is unclear whether the microglia[neural portion of immune system] did not detect the cancer cells, or if they chose not to treat them as a threat, but in the end, the intrusive cells were not harmed in their transit within the brain. It seemed as though the invaders, while cancerous, were still treated as part of the whole within the body. Unfortunately upon entering the brain, they proliferated, and quickly. It wasn't long until the functional neural cells were being choked of resources. Soon enough, the patient passed.

The third and final patient had a unique reaction. When the cancer cells reached the brain, they were not immediately attacked. They proliferated for a short while. Certain factors began to be released from both the cancerous and glial cells. Upon this, microglia were activated in certain portions of the brain but not all, and consumed about 80% of the cancerous cells in the brain. Over time, production rate of cancer cells, and microglia consumption of cells diminished to low amounts. Also, new factors were beginning to be released in the original tumor; as well as an increase in the cancer-related factors from the brain. As time passed notable changes in the patient were taking place, such as personality differences, as well as an odd change in dietary habits. What was most astounding was that the original tumor began to shrink, as if they were re-differentiating to their original purpose. As this happened, the tumor cells within the brain had subsided as well. It was found later that there were still trace amounts of tumor cells left in the brain only. While the personality changes in this patient remained, he was the only one to survive.

It was quite an interesting revolution.