DNA analysis of neoplasia: an introduction for the family physician. Pathologic evaluation of a neoplastic process has traditionally consisted of microscopic examination of a stained section of tissue. Although this method is generally reliable when performed by an experienced pathologist, the morphologic features of a lesion may not consistently predict biologic behavior. The DNA content of tumors can be studied with a flow cytometer to help determine the prognosis and risk of tumor recurrence. DNA analysis of a neoplasm may provide the clinician with important prognostic information and, at some future date, may help direct chemotherapy or other treatment protocols. 