Oncogenes can be activated by damaged or altered chromosomes. Oncogenes influence a cells structure and function. This process creates a new gene called the bcr-abl gene. The bcr-abl gene is an oncogene. It is believed that the bcr-abl oncogene on the Ph chromosome causes the uncontrolled growth of leukaemia cells.
Symptoms depend upon the stage of disease.
The chronic phase may last for 3-6 years. Symptoms are often mild, with many patients being incidentally picked up on routine medical examination or blood testing for other reasons. Anaemia may be one of the presenting symptoms. Anaemia develops when the leukaemia cells gradually overrun the bone marrow, inhibiting the production of healthy blood cells. Other symptoms may include abdominal tenderness and fullness, suggesting the involvement of the spleen by the leukaemia.