Yes, alcohol can cause some types of cancers. Liver cancer can be caused by cirrhosis of the liver; many times the result of a lifetime of heavy drinking. Alcohol can also cause oral and esophagus cancer as well. Medical researchers will likely discover more links between heavy drinking and other forms of cancer.
Most forms of alcohol are dangerous, especially in large quantities. Alcohol, including wine and strong spirits, were used as disinfectants before other methods of sterilizing wounds became available. This stuff kills cells. No surprise, really, if either the alcohol itself, or the additives that create flavor, damage cells or immune systems enough for cancer to move in.
Scientific evidence suggests that certain kinds of cancer, such as liver cancer is caused by alcoholism. There are also other factors involved, and a moderate amount of alcohol can help prevent cancer. The bottom line is that you should drink in moderation or not at all in order to stay safe and healthy.
While alcohol may increase your risk of developing certain types of cancer, I do not believe that alcohol itself directly causes cancer. While recent research shows how an increase in cancer risk goes up with any level of alcohol consumption, researchers do not yet know exactly what about the alcohol does this. I think further research needs to be conducted before determining that alcohol indeed causes cancer.