Chromosome Preparation for Myeloid Malignancies.

Many cases of myeloid malignancies are associated with recurring cytogenetic aberrations. Chromosomal analysis can aid in diagnosis, predict prognosis, and disclose subsequent clonal evolution. Three different cell culture methods: direct harvest, nonsynchronized culture, and synchronized culture are usually prepared if the nucleated cell counts in marrow blood are sufficient. Synchronized culture is the first choice of method in myeloid malignancies, whereas the direct method can be omitted if the cell count is low. The aseptic culture technique is strictly followed until harvesting procedure. For synchronized culture, uridine and fluorodeoxyuridine are added as blocking reagents and released by thymidine on the following day. Harvesting steps of the cultures involved colcemid exposure, hypotonic treatment, and Carnoy's fixation. The cells are then ready for slide making and banding for chromosomal analysis.

Chromosome Recognition.

Chromosomal analysis of human cells serves to characterize aberrations of chromosome number and structure. Individual chromosome can be identified precisely by recognition of its morphological characteristics and staining patterns according to specific landmarks, regions, and bands as described in the ideogram. Since the quality of metaphases obtained from malignant cells is generally poor for karyotyping, a practical and accurate chromosome recognition training guide is mandatory for a trainee or newly employed cytogenetic technologist in a cancer cytogenetics laboratory. The most distinguishable bands for each chromosome are described in detail in this chapter with an aim to facilitate quick and accurate karyotyping in cancers. This is an indispensable chromosome recognition guide used in a cancer cytogenetics laboratory.