What difficult issues does Sherman Alexie address in "The Approximate Size of My Favorite Tumor"?

Sherman Alexie's short story is darkly funny. In it, the narrator, Jimmy Many Horses, turns to laughter to deal with the painful and difficult issues that present themselves in his life. As Jimmy says, "Humor was an antiseptic that cleaned the deepest of personal wounds." In other words, humor is like a medicine that cleanses wounds.

The most pressing problem is that Jimmy is dying of cancer, and he has large tumors that resemble baseballs riddling his body. His wife, Norma, is angry at him for making a joke even out of dying, and she leaves him temporarily as a result. The other problem that Norma and Jimmy deal with is racism and unfair treatment of Native Americans. In one flashback, Jimmy recalls an incident in which a Washington State patrolman shook him and Norma down and took their money, even though they had not done anything wrong. If they had protested, he would have charged them with crimes they did not commit. Jimmy responds to all these difficult issues with laughter.