FISH Probes

BLADDER

Amplification at the 5p152.2 locus is strongly linked to high-grade, advanced-stage bladder tumors and rapid tumor cell proliferation in urinary cancer. Cytogenic analysis is demonstrated that 5p might be involved in translocations and/or formation of isochromosomes in a substancial number of bladder tumors. Gains at Chromosomes 3, 7, and 10 are seen more frequently in urothelial tumors.

BREAST

Amplification of HER-2 has been demonstrated to predict poor clinical outcome in breast cancer patients, and is shown to be associated with resistance to certain chemotherapeutic agents. Determining amplification of HER-2 is crucial in the guidance of treatment decisions for the use of HER-2-targeted therapies, and is becoming a standard recommendation in the pretreatment work-up of patients with invasive breast cancer. Loss of PTEN may have prognostic significance in breast cancer, and was shown to be associated with poor clinical outcome in HER-2 positive disease.

CERVICAL

Amplification of TERC appears to be an important associated genetic event in the progression of cervical dysplasia to invasive cancer. 5p15.2 is another locus which displays significant amplification in association with progression to aggressive disease. Increases in genes at and near 20q13 have been specifically associated with cervical cancer progression to higher grade lesions.

GASTRIC/ESOPHAGEAL

The set of FISH probes consisting of MYC, CDKN2A (9p21), ERBB2 (HER-2), and 20q13.2 can provide high sensitivity and specificity for the detection of Barrett’s associated neoplasia and allow for the differentiation between esophageal adenocarcinoma and high-grade dysplasia (EAC/HGD) or low-grade dysplasia and non-dysplasia (LGD/ND).

LEUKAEMIA

LUNG

Recently, the ALK-EML4 fusion gene has been shown to be an important biomarker for ALK tyrosine kinase inhibitor (crizotinib) treatment in NSCLC, and Biocare’s unique ALK-EML4 Tri-Color allows detection of ALK break-apart and EML4 fusion in the same test. Patients with either ROS1 rearrangement or MET amplification have also been shown to respond to crizotinib treatment. Other small molecule kinase inhibitors have shown activity against RET break apart mutants.

MELANOMA

Cytogenetic abnormalities in RREB1, MYB, and CCND1 loci detected by FISH are sensitive and specific markers of malignancy valuable for differentiating between benign and malignant melanocytic lesions. CDKN2A is frequently deleted in melanoma of all primary subtypes, and loss of both CDKN2A and CCND1 correlate with poor responses to inhibitor therapy.

MYELOMA

PROSTATE

With disease panels like PTEN, TMPRSS2/ERG and Androgen Receptor (AR), more informative disease stratification is possible. MYC amplification and NKX31 allelic loss are significant predictors of prostate cancer progression and aggressiveness. The novel tumor suppressor PHLPP1 is deleted as frequently as PTEN in prostate cancer, and may represent a therapeutic target for suppressing oncogenic pathways.

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