How it all began: Cancer cytogenetics before sequencing

According to Boveri's hypothesis, chromosome abnormalities were the cellular changes causing the transition from normal to malignant proliferation. Technical difficulties prevented reliable visualization of mammalian chromosomes, in both normal and neoplastic cells, throughout the entire first half of the 20th century. Nowell and Hungerford's discovery greatly stimulated interest in cancer cytogenetics in the early 1960s, but for several reasons, the Ph chromosome long remained an exceptional finding. The advent of molecular genetics in the 1980s and the development of a range of powerful molecular cytogenetic technologies, such as fluorescence in situ hybridization (FISH), multicolor FISH, comparative genomic hybridization (CGH), various array-based genotyping technologies, and DNA and RNA sequencing, have widened one's knowledge and understanding of the molecular mechanisms that are operative in neoplastic initiation and progression. In the 100 years since Boveri first postulated that chromosome change may initiate the carcinogenic process, cancer cytogenetics has come of age.