A 74-year-old female was diagnosed with the autoimmune inflammatory disease temporal arteritis and treated with high and low doses of prednisone over a period of 6 years. During that time, she developed cancers of the lung and colon as well as a soft tumor mass on lumbar vertebrate L3. She also experienced a series of debilitating and disabling symptoms while on prednisone treatment. A temporal analysis of the association of prednisone therapy and immune markers to the successive appearance of the malignant tumors strongly suggests that in the absence of a functioning natural immune and surveillance system by treatment with the immune knockout drug prednisone, spontaneous, multiple independent mutations occurred in several sites in the organ systems of this patient. Over a period of time, these developed into malignant cancers, including a lung nodule which became cancerous 256 days later, as well as the cancers of the colon and a soft tumor mass on lumbar vertebrate L3.