ALCOHOL may accelerate the growth and spread of existing cancers as well as causing certain types of tumour. The finding may also explain why heavy drinkers often have red noses.
There are well-established links between heavy drinking and various forms of cancer, especially if people smoke as well. The main organs affected are those which bear the brunt of the alcohol exposure: the mouth, throat, stomach and liver. How alcohol makes cancer start and spread has been a mystery, although some experts think that the culprits are substances formed as alcohol breaks down, such as acetaldehyde.
To find out if alcohol also affects existing cancers, Jian-Wei Gu鈥檚 team at the University of Mississippi Medical Center in Jackson, Mississippi, injected chick embryos in eggs with human fibrosarcoma cells, like those which cause bone and muscle cancers. Then he injected salty water into half the eggs and alcohol into the rest, at concentrations typical of the blood levels that occur in moderate drinkers.
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He found tumours grew twice as large in the alcohol-treated embryos. And the blood vessel networks of the tumours in the alcohol-treated eggs were eight times as extensive and invasive.
Gu鈥檚 team established that alcohol boosts the production of certain growth factors, including vascular endothelial growth factor (Cancer, DOI: 10.1002/cncr.20781). Crucially, the higher the concentration of alcohol, the more growth factor was produced.
These factors stimulate the growth of blood vessels that feed a tumour, helping it grow and invade other parts of the body. 鈥淲e haven鈥檛 shown that alcohol causes cancer or mutates ordinary cells,鈥� says Gu. 鈥淏ut our study shows that alcohol stimulates the growth and spread of cancer.鈥� He says that every day our bodies produce abnormal cells which our immune system destroys before they become malignant. But if these cells evade the immune system and multiply to form a small lump, alcohol could help them grow their own blood supply and turn cancerous.
鈥淎lcohol could help cells that have evaded the immune system grow their own blood supply and turn cancerous鈥�
Gu says that those at high risk of cancer, such as women with mutations that increase their chances of getting breast cancer, should not drink alcohol. But for people in good health, moderate consumption is fine and may even be beneficial for your heart.
鈥淲hat鈥檚 still missing is how alcohol makes tumours start,鈥� says Chris Boshoff of University College London and Cancer Research UK. Since the type of cancer grown in the eggs is not especially prevalent in drinkers, the relevance of Gu鈥檚 research is difficult to gauge, he adds.
However, the link with blood vessel formation could explain the red noses seen in many heavy drinkers, as well as spider naevi, the tiny networks of blood vessels visible under the skin of drinkers, Boshoff adds. 鈥淚t would be interesting to investigate whether drinkers with spider naevi are more likely to develop cancer.鈥�
