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cells to form blood vessels around them to fulfill a high nutrient requirement. Moreover, they become metastatic.”
“What is that?” he wondered.
“Metastasis is the most dreadful property of cancer cells. Sometimes the cancer cells loosen themselves from their original site, sneak into blood vessels by passing through the gap between endothelial cells, circulate throughout the body, again exit the blood vessel,andmakeasecondarytumorinanother distant organ. Cancer cells from the skin, for example, celled melanoma, can migrate to lung, liver, lymph nodes, and brain, even to bones.”
“Why do people die of cancer? Isn’t there any medicine to treat this?” He looked crestfallen.
“Of course, there are a number of therapies to treat cancer. First is surgery, in which doctors surgically remove the affected part if possible. But some
residual cells may still be there,
which can develop a tumor
in the near future. Second is chemotherapy in which some
chemical compounds are
injected into patients, and
they can directly kill rapidly
growing cancer cells. But very
often, these drugs cannot
discriminate between rapidly
dividing healthy normal cells
and malignant cells. Thus,
our normal cells get affected,
too. You may often find that
cancer patients undergoing chemotherapy have developed
baldness. The third is
radiotherapy in which the particular affected site is exposed to a special kind of ray is given to the particular affected site. This can also affect the nearby normal cells. Fourth approach is immunotherapy. Even a combination of two
Mr. Anirban Sarkar || 103
types of therapy is also used.”
“What is your research interest among
these?” Arko stopped me and asked curiously. “I am working on cancer immunology and
immunotherapy,” I said.
“Immunotherapy is comparatively new.
Our body has its own defense system, called the immune system. The immune system has an arsenal of soldiers that can kill a wide array of deadly pathogens that are trying to infect us daily. Cytotoxic T cells, dendritic cells, macrophages, neutrophils, etc., can detect cancer cells and kill them.”
“Like the Avengers!” he said astonishingly.
“Yes, like the Avengers,” I said. He is a big fan of Marvel Comics and very recently he has seen Avengers Endgame.
I continued, “In this therapeutic approach, different kinds of immune components such as specific antibodies against tumors such as – anti-PD-1, anti-PDL-1, and anti-CTLA-4
antibody, or engineered immune cells such as CAR-T cells, etc., are used. Even in the previous year, two scientists James P. Allison and Tasuku Honjo won the Nobel Prize in Physiology and Medicine for their discovery of CTLA-4 and PD-1, respectively. They are the checkpoint inhibitors.”
“What is a checkpoint inhibitor?” he asked.
“Checkpoint inhibitors ensure that our immune system does not attack our own cells. Cytotoxic T cells have the checkpoint inhibitors on their surface, and if they attack a
healthy cell, our body can suppress them through these checkpoint inhibitors, like an off switch.”
“So, our immune system has its own
Metastasis is the most dreadful property of cancer cells. Sometimes the cancer cells loosen themselves from their original site, sneak into blood vessels by passing through the gap between endothelial cells, circulate throughout the body, again exit the blood vessel, and make a secondary tumor in another distant organ.