Anaplastic lymphoma kinase (ALK) fusion oncogene positive non small cell lung cancer

Anaplastic lymphoma kinase (ALK) fusion oncogene positive non small cell lung cancer refers to a specific set of non small cell lung cancers that contain an inversion in chromosome 2. They are associated with specific clinical features, including never or light smoking history, younger age, and adenocarcinoma with a signet ring or acinar histology.

Epidemiology

 It may account for 4-5 % of non small cell lung cancers.

Pathology

They resulting in the novel fusion oncogene EML4-ALK rearrangement is transforming both in vitro and in vivo and defines a distinct clinicopathologic subset of NSCLC. ALK gene arrangements are "largely but not entirely" mutually exclusive with epidermal growth factor receptor (EGFR) and KRAS mutations.

Radiographic features

Since it is a new discovery there are not many imaging publications on this topic (i.e. one or two studies per finding). Some reported features include:

• more central tumor location
• absence of pleural tail
• associated large pleural effusion
• relatively smaller size
• lower tumor disappearance rate (TDR) rate following treatment
• may appear as more solid masses with lobulated margins

Treatment and prognosis

They are more responsive to anaplastic lymphoma kinase (ALK) and c-Met receptor kinases such as crizotinib.