Review of conventional and molecular cytogenetic techniques and their use in the diagnosis and prognosis of cancer

Abstract

Cytogenetic analysis of tumour cells has provided important information for understanding the biology of cancer. Around 100,000 clonal chromosomal abnormalities belonging to more than 30,000 human neoplasms are described in the latest catalogue of chromosome aberrations in cancer. Some of them have been molecularly characterised, making possible the identification of new oncogenes and tumour suppressor genes involved in tumourigenesis. In haematologic neoplasms and sarcomas, cytogenetic analysis is a powerful tool of diagnosis and prognosis, and has been incorporated into routine laboratory methods. However, in solid tumours, cytogenetics have been hampered by difficulties in obtaining high quality metaphase spreads, or by the presence of multiple cellular clones or complex karyotypes. The development of fluorescence in situ hybridisation techniques (FISH) has provided a notable advance in cancer cytogenetics, especially in solid tumours. Nowadays, the FISH technique has evolved into numerous variants, such as comparative genomic hybridisation (CGH), spectral karyotyping (SKY) or multiple FISH (M-FISH), among others. All these techniques constitute a new discipline named molecular cytogenetics, and provide new and more accurate methods for detecting chromosomal aberrations in tumour cells. The combination of conventional cytogenetics, FISH and molecular analysis makes possible more accurate diagnoses, improved classification of neoplasms in subgroups of different prognostic value, and the post-treatment follow-up of patients affected with cancer. In this review, the different genetic techniques are described as well as their impact on the diagnosis and prognosis of cancer.