Acquired Chromosome Abnormalities in Cancer

In addition to the constitutional cytogenetic chromosomal abnormalities that are present at birth, somatic chromosomal changes can be acquired later in life and are often associated with malignant conditions. As with constitutional abnormalities, somatic changes can include the net loss of chromosomal material (due to a deletion or loss of a chromosome), net gain of material (duplication or gain of a chromosome), and relocation of DNA sequences (translocation). Cytogenetic changes have been particularly well studied in (1) leukemias, e.g., Philadelphia chromosome translocation in CML [t(9;22)(q34.1;q11.2)]; and (2) lymphomas, e.g., translocations of MYC in Burkitt's [t(8;14)(q24;q32)]. These and other translocations are useful for diagnosis, classification, and prognosis. Analyses of cytogenetic changes are also useful in certain solid tumors. For example, a complex karyotype with Wilms' tumor, diploidy in medulloblastoma, and Her-2/neu amplification in breast cancer are poor prognostic signs. For detailed discussion of cancer genetics, see Chap. 79.

Reff:

Harrison's Internal Medicine > Chapter 63. Chromosome Disorders >