EML4-ALK positive lung cancer

src: clincancerres.aacrjournals.org

EML4-ALK positive lung cancer is a medical term that refers to a primary malignant lung tumor whose cells contain a characteristic abnormal configuration of DNA wherein the echinoderm microtubule-associated protein-like 4 (EML4) gene is fused to the anaplastic lymphoma kinase (ALK) gene. This abnormal gene fusion leads to the production of a protein (EML4-ALK) that appears, in many cases, to promote and maintain the malignant behavior of the cancer cells.

The transforming EML4-ALK fusion gene was first reported in non-small cell lung carcinoma (NSCLC) in 2007.

Video EML4-ALK positive lung cancer

Classification

Most lung carcinomas containing the EML4-ALK gene fusion are adenocarcinomas.

Some studies suggest that the papillary adenocarcinoma and the signet ring cell adenocarcinoma variants are more likely to carry this fused gene than other histological variants.

Maps EML4-ALK positive lung cancer

Epidemiology

EML4-ALK gene fusions occur almost exclusively in carcinomas arising in non-smokers. About 4% of non-small-cell lung carcinomas involve an EML4-ALK tyrosine kinase fusion gene. 4-6% of lung adenocarcinomas involve the fusion gene.

EML4-ALK mutation rarely occurs in combination with K-RAS or EGFR mutations.

src: clincancerres.aacrjournals.org

Signs and symptoms

The signs and symptoms of this lung cancer variant seem to mimic those of the underlying major cell type.

src: cancerimmunolres.aacrjournals.org

Screening

A 2011 consensus recommendation from 37 Canadian lung cancer specialists found that, as of June 2011, there was insufficient evidence to recommend routine screening of lung cancer specimens for EML4-ALK fusions, but that may soon change.

There is a companion diagnostic test to detect the EML4-ALK fusion protein.

src: clincancerres.aacrjournals.org

Treatment

Crizotinib is a targeted therapy (FDA approved in 2011) that targets the EML4/ALK fusion gene.

Alectinib was approved (for this) by Japan in 2014 and by US FDA in 2015.

src: mct.aacrjournals.org

Prognosis

Treatment with crizotinib achieves 60% response rate. However, crizotinib showed no improvement on overall survival compared to chemotherapy. This may be due to the fact that there was a 70% crossover rate to crizotinib in patients treated initially with chemotherapy. Also, patients who tested negative for EML4/ALK fusion had a response rate to crizotinib of up to 35%.

src: clincancerres.aacrjournals.org

References

src: cancerres.aacrjournals.org

External links

• Entrez Gene EML4 echinoderm microtubule associated protein like 4 Homo sapiens

Source of article : Wikipedia