Anti-ALK Antibodies in Patients with ALK-Positive Malignancies Not Expressing NPM-ALK.

Patients with Nucleophosmin (NPM)- Anaplastic Lymphoma Kinase (ALK) fusion positive Anaplastic Large Cell Lymphoma produce autoantibodies against ALK indicative of an immune response against epitopes of the chimeric fusion protein. We asked whether ALK-expression in other malignancies induces specific antibodies. Antibodies against ALK were detected in sera of one of 50 analysed ALK-expressing neuroblastoma patients, 13 of 21 ALK positive non-small cell lung carcinoma (NSCLC) patients, 13 of 22 ALK translocation-positive, but NPM-ALK-negative lymphoma patients and one of one ALK-positive rhabdomyosarcoma patient, but not in 20 healthy adults. These data suggest that boosting a pre-existent anti-ALK immune response may be more feasible for patients with ALK-positive NSCLC, lymphomas and rhabdomyosarcomas than for tumours expressing wild-type ALK.