Which of the following are not cancerous in nature?

Polycythemia is characterized by an increase in the number of red blood cells in the bloodstream, which is not inherently cancerous. It can be caused by various factors, including chronic hypoxia or certain conditions like polycythemia vera, which is a myeloproliferative disorder that can resemble cancer but is primarily classified as a type of blood disorder rather than a malignancy.

Leukemia and lymphomas are both types of cancers that affect the blood and lymphatic system. Leukemia is a cancer of the bone marrow and blood that leads to the overproduction of abnormal white blood cells, while lymphomas affect the lymphatic system, causing the proliferation of lymphoma cells. Hemophilia, on the other hand, is a genetic bleeding disorder and not cancerous; as such, it does not involve uncontrolled cell growth. Thus, among the choices provided, polycythemia stands out as the condition that is not considered cancerous in nature.