Molecular genetics - neoplasia

Specimen:

Unfixed tumour biopsy.

Blood or bone marrow aspirate.

Method:

See Molecular genetics.

Application:

Diagnosis and characterisation of neoplastic disorders including the detection of abnormalities which may be of prognostic significance.

Diagnostic approaches include the detection of oncogenes (eg, N-myc in neuroblastoma, bcr-abl in chronic myeloid leukaemia), the detection of clonal rearrangements of the T cell receptor or immunoglobulin genes in lymphoid malignancies, and the demonstration of gene deletion or mutation of a tumour suppressor gene (eg, p53, WT1) or oncogene (eg, c-myc).

The techniques may be used to detect minimal residual disease after therapy eg, in acute leukaemia and lymphoma.

In some instances the tests may be done in conjunction with cytogenetic studies (eg, for the Philadelphia chromosome in chronic myeloid leukaemia); see Cytogenetics - oncology.

Interpretation:

The detection of a specific genetic abnormality contributes to the definitive diagnosis of some malignancies and may assist in determining prognosis.

The role of molecular genetics in assessing the inherited risk of some malignancies (eg, BRCA-1, BRCA-2 for breast cancer) is currently unclear, but it is the standard of care in other situations (eg, retinoblastoma).

See also RCPA Catalogue of Genetic Tests and Laboratories.

Reference:

Boxer LM. Annu Rev Med 1994; 45: 1-11.