ALK Screen (lung cancer)
Also known as: ALK IHC (lung cancer); ALK FISH (lung cancer)« Back to test list
Gene fusions involving the ALK gene and other gene partners occur in a subset of non-small cell lung cancers (NSCLC). Such fusions carry implications regarding selection of and response to therapies.
The presence of an ALK rearrangement in NSCLC detected by Fluorescent In Situ Hybridisation (FISH) analysis is associated with increased sensitivity to ALK tyrosine kinase inhibitor therapy.
The ALK FISH test is useful as a second-line test in NSCLC following i) a negative EGFR mutation result, and/or ii) to confirm an ALK rearrangement suggested by ALK over-expression on immunohistochemistry (IHC) studies. Tumours that do not have ALK over-expression on IHC are highly unlikely to have an ALK rearrangement.
This is an assay for non-heritable mutations. It does not raise issues of ethics or consent that are different from most other investigations ordered in the routine care of a patient.
IHC using an assay designed to detect ALK overexpression in NSCLC samples. If IHC is equivocal or positive, this is followed by FISH analysis, using probes to identify rearrangements resulting in the fusion of ALK with a partner gene.
This test is usually requested by an oncologist. Please use the specific request form (see link at right).
The standard ALK screening process involves an initial IHC assay. If this is negative, no further testing will be carried out. If ALK IHC is positive, ALK FISH is recommended to confirm the presence of an ALK rearrangement.
ALK FISH can also be requested separately (regardless of the ALK IHC result). If required, please denote this on the request form.
Formalin fixed, paraffin-embedded tissue (FFPE) – 10 sections of 4 uM thickness, dried overnight at 37°C onto charged/coated slides.
Please stain the first section with H&E, and label each slide with patient and block identifiers. Label the unstained sections sequentially (slides 2-10). The request should be accompanied by a completed Somatic Mutation Testing Request Form and a copy of the original histopathology report.