Don't exceed recommended alcohol consumption.
There seems to be a relationship between alcohol intake and the higher incidence of some tumours.
The study of this interaction, though, is not simple. It is estimated that excessive alcohol intake increases the risk of tumours of the oral cavity, pharynx, esophagus, larynx, bowel, and breast cancer in women, and seems to be connected to the primary risk of liver cancer.
Alcohol is a difficult factor to isolate. It is frequently associated with other risk factors like smoking and a sedentary life, therefore it is complex to design studies targeted to this specific factor.
What is the "safe" daily alcohol intake, i.e. the threshold below which there is no cancer risk?
European guidelines report 2-3 glasses of wine or beer for men, and even less for women.
In this case, like in others, rely on common sense: the negative effects of alcohol abuse on health are well-known and documented.