Karyotyping and Chromosomal Aberrations in Cancer: Molecular and Diagnostic Biomarkers

Chromosomal abnormalities induce genomic instability and are associated with cancer hallmarks. Chromosomal abnormalities can be categorised into structural and numerical aberrations and are seen under a light microscope. Given the ease of detecting and observing such changes using karyotyping, chromosomal aberrations may be a useful diagnostic tool. For example, the discovery of the Philadelphia chromosome was a cytogenetic hallmark of chronic myeloid leukaemia and acute lymphoblastic leukaemia. Thus, this chapter explores potential aberrations which have the potential to be used as cancer markers in a clinical setting. Recurrent structural aberrations with known genetic mutations are observed in cancers of the bones, lungs, salivary glands, soft tissue, stomach, thyroid, and uterus. The association of these genetic alterations with various cancers suggests a causative role of structural aberrations in carcinogenesis and is characteristic of some cancers. Additionally, mono- and tri-somies, known as aneuploidy, are common to all cancer types, however, their roles as a cause or consequence are difficult to establish due to the sheer loss or gain of genetic material, respectively. Cancers with the most frequent trisomies, include Ewing’s sarcoma of the bone, astrocytoma of the brain, and renal adenocarcinoma. Common cancer monosomies include meningioma of the brain and ovarian adenocarcinoma. These chromosomal aberrations forge the path to a better understanding of cancer genetics. Though there are potential chromosome markers in cancer, the heterogeneity of cancer genetics makes this a challenging tool to incorporate into current oncological diagnostic guidelines.