Laboratory study of breast cancer using conventional and molecular cytogenetics.

Currently, the factors associated with tumor initiation, progression, invasion and metastasis as well as the complex relationship between the genetics of breast cancer are not clearly understood. It is known, however, that the risk of developing breast cancer increases with age, family history of breast cancer, and not bearing a child by age 30. Most breast cancer cases (i.e., greater than 70 percent), however, occur in women who have no identifiable risk factors. The basic methods of treatment (e.g., surgery, chemotherapy and radiation) used today are the same as those used in the 1930s. The current criteria for breast cancer staging include pathologic parameters, such as tumor size and nodal involvement, histologic and cytologic parameters, such as histologic grade, and biologic parameters such as age of the patient, hormone (estrogen and progesterone) receptor status, oncogene activation (e.g., c-myc and HER-2/neu) and tumor suppressor gene inactivation (e.g., p53). Although there is evidence that some of these factors may offer some utility in prognosis, the optimal combination of independent prognostic factors remains elusive. Thus, the need to explore other potential biomarkers is pressing. Laboratory study of breast cancer using conventional and molecular cytogenetics, together with other forms of analysis, will lead to an improved repertoire of biological markers in the future.