Nicotine and cancers (yes, that’s a plural)

The direct link between cigarette smoking and lung cancer is well-established. But what about other types of cancer?

Nicotine is one of the major components of tobacco and can be found in high concentrations in the blood and the urine of cigarette smokers. Although not considered a full-blown carcinogen that promotes tumor development, it is however suspected to have a growth-enhancing effect on existing cancer cells. This post looks at recent research on the link between nicotine and different types of cancer.

Nicotine and breast cancer

This study published in Cancer Research, a journal of the American Association for Cancer Research suggests that nicotine can have a potentiating role in tumor development. The researchers demonstrated through a series of lab test

“… that breast epithelial-like MCF10A cells and cancerous MCF7 cells both express several subunits of nAChR (nicotine receptor), that when bound, initiate a signaling process, potentially increasing cell growth and migration.”

As a carcinogen, nicotine does not seem to act alone but rather combines with other carcinogens with disastrous effect. According to the researchers, “…nicotine, possibly through perturbing cell cycle checkpoints, potentiates tumorigenesis in mammary cancer-prone or cancer cells.”

Aside from promoting the development of breast cancer, nicotine as a cocarcinogen is also linked to the spread of cancer through tumor migration from the breast to other organs.

Nicotine and bladder cancer

In another study, Taiwanese researchers observed that nicotine can de detected in significant quantities in the urine of cigarette smokers. The study aimed to investigate “whether there is nicotine-induced bladder epithelial cell proliferation and to identify the signaling transduction pathway regulated by nicotine.” The results suggested that nicotine exposure is a major risk factor for bladder cancer.

Nicotine and apoptosis

Apoptosis is a process wherein our body destroys unwanted cells. It is sometimes called “programmed cell death” and is protective mechanism that can protect us from cells that might potentially turn harmful (e.g. cancerous). Several studies suggest that nicotine may have some adverse effect on apoptosis. This recent study by Stanford University researchers showed that continued smoking during cancer treatment can lead to resistance to chemotherapy among lung cancer patients due to the anti-apoptotic effect of nicotine.

Nicotine in the gastrointestinal tract

This study by Chinese researchers show that nicotine can have some “aggravatory effect on … gastric mucosa injury” induced by the bacteria Helicobacter pylori, one of the major causes of gastric ulcers.

Nicotine effect on different human cancer cells

This study by researchers at the H. Lee Moffitt Cancer Center and Research Institute tested the effect of nicotine on different types of human cancer cells. The results show that aside from an inductive effect on lung cancer cell lines, it also induced proliferation of and invasion by breast and pancreatic cancer cells.

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