Molecular Testing in Blood Cancers — From Mutation to Monitoring

What tests are used

Karyotyping detects chromosomal rearrangements; FISH targets specific loci; PCR detects fusion transcripts and mutations; next-generation sequencing panels assess many genes at once. The choice depends on the suspected disease and the question being asked — diagnosis, risk, treatment selection or monitoring.

• Karyotype for chromosomal abnormalities
• FISH for specific translocations and deletions
• PCR for fusion transcripts and mutations
• NGS panels for diagnosis and risk
• Molecular monitoring for disease response

What molecular results change

In AML, mutations such as NPM1, FLT3 and IDH1/2 inform risk and targeted therapy. In CML, BCR-ABL1 monitoring guides TKI therapy. In CLL, TP53 status influences treatment choice. In myeloma, FISH identifies high-risk disease. A variant of uncertain significance should not be over-interpreted, and testing should be repeated when disease evolution is suspected.

• Risk stratification in AML and MDS
• TKI selection and monitoring in CML
• TP53 and IGHV status in CLL
• FISH risk in myeloma
• Repeat testing when disease evolves

Guidelines referenced:

• European LeukemiaNet recommendations
• WHO Classification of Haematopoietic and Lymphoid Tumours
• NCCN Guidelines — Haematological Malignancies