BONE MARROW, LEUKEMIC BLOOD AND SOLID TUMOUR ANALYSIS
Useful information about leukemias, lymphomas, and other related cancers may be obtained from chromosome analysis of cultured bone marrow and periferal blood cells and other laboratory techniques. The results of these tests can help classify the type of cancer to allow for more accurate treatment, assess the effectiveness of a treatment, and help predict a patient's prognosis.
Chromosomes in leukemia.
Chromosomes are folded DNA units of genetic information. There are 46 chromosomes in all human cells (except reproductive cells), arranged into 23 pairs. Chromosomes carry of thousands of genes, which control growth and development of the entire human body. An abnormality in the function of specific genes on the chromosomes in the cells can lead to cancer. An example of a common chromoaomal change that can lead to malignancy is a translocation (a rearrangement of between parts of nonhomologous chromosomes), for example, almost 90% of the cases of chronic myelogenous leukemia (CML) are caused by a translocation between chromosomes 9 and 22, in which areas of the two chromosomes switch places. This rearrangement disrupts the genes in these areas on the chromosomes which eventually lead to the CML.
Rearrangement of the Abl oncogene region on chromosome 9 and the BCR region on chromosome 22
The CML associated with this genetic change does not necessarily mean that it is inherited. Most chromosome abnormalities related to cancers are acquired sporadically throughout life and we would not expect an increased risk for the same chromosome abnormality to occur in a patient's children.
The Benefits of Laboratory Testing.
Chromosome analysis can assist to define the type of cancer. This can aid in identifying an appropriate treatment protocol and in predicting prognosis.
Fluorescent in situ hybridization (FISH) is a specialized analysis technique that can detect low percentages of abnormal cells in the bone marrow or peripheral blood after treatment. Fish can be used to monitor the disease progression and possible remission status. FISH testing often detects abnormal cells present before clinical symptoms reappear facilitating re-implementation of treatment sooner.