Cytogenetics. An evolving role in the diagnosis and treatment of cancer.

Conventional cytogenetics has been used for many years in the diagnosis and follow-up of myeloproliferative disorders. Molecular techniques including FISH and gene rearrangements are complementary in the evaluation of myeloproliferative and myelodysplastic disorders. Lymphomas and lymphocytic leukemias have nonrandom cytogenetic patterns that are useful in the clinical diagnosis, prognosis, and therapeutic follow-up. Solid tumors have complex karyotypic and genetic abnormalities, and clinical utilization of conventional cytogenetics and molecular techniques is in the developmental stages of applicability. The benefits of karyotype analysis in myeloproliferative and lymphoproliferative diseases include guidance for diagnostic and therapeutic approaches as well as assessment of minimal residual disease. Conventional cancer cytogenetics and commercially available FISH reagents enhance these applications. Molecular diagnostic techniques are analytically sensitive and specific. The complexities of the function and role of genetic abnormalities in solid tumors present challenges in the choice, interpretation, and application of conventional cytogenetic and molecular data. These challenges offer exciting potential for future advances.