Identifying patients with late-stage, non-small cell lung cancers who may benefit from treatment with the drug Xalkori.
This test is always reflexed when EGFR is initially ordered.
1. A pathology report is required in order for testing to be performed. Acceptable pathology reports include working drafts, preliminary pathology or surgical pathology reports.
2. A reason for testing must be provided. If this information is not provided, an appropriate indication for testing may be entered by Mayo Clinic Laboratories.
Tissue Block Collection Instructions: Submit a formalin-fixed, paraffin-embedded (FFPE) tumor tissue block. Blocks prepared with alternative fixation methods may be acceptable; provide fixation method used.
Submit tissue block or slides.
This test is intended to be used for therapeutic purposes in pulmonary carcinoma. This FISH assay does not rule out other chromosome abnormalities.
While results may indicate the likely response to ALK inhibitor therapy, selection of treatment remains a clinical decision.
Mayo Clinic Laboratories
A positive result (ALK rearrangement identified) is detected when the percent of cells with an abnormality exceeds the normal cutoff for the ALK probe set.
A positive result suggests rearrangement of the ALK locus and a tumor that may be responsive to ALK inhibitor therapy.
A negative result suggests no rearrangement of the ALK gene region at 2p23.
A specimen is considered positive if >50% demonstrate a signal pattern consistent with an ALK rearrangement and considered negative if <10% of cells are positive. If the results are equivocal (>10% and <50%), an additional 50 cells are scored and would be considered positive if >15% of cells exhibit a signal pattern consistent with an ALK rearrangement and negative if <15% of cells exhibit an ALK rearrangement.