CD30 expression in non-small cell lung cancer with and without ALK gene rearrangement.

e22146 Background: 3-5% Non-Small Cell Lung Cancer (NSCLC) harbors ALK gene translocation (ALK(+)) for which targeted ALK inhibitor has greater efficacy and tolerance than cytotoxic chemotherapy. However, resistance to ALK inhibition inevitably occurs and new therapeutic targets are urgently needed in this unique patient population. Interestingly, CD30, a TNF receptor super family member, is commonly expressed in anaplastic large cell lymphoma which is another malignancy associated with ALK gene arrangement in a majority of cases. Targetable CD30 could represent a new therapeutic target in ALK(+) NSCLC. CD30 expression has been observed in a study of 875 multiple types of non-lymphomatous malignancies (3-33%), including one case with small cell lung cancer (4%). The expression of CD30 in NSCLC, especially in ALK(+) NSCLC, is largely unknown. Methods: CD30 expression in the NSCLC cell lines A549, H358, H1666 and H1299 (none containing ALK gene translocation) was tested by western blot, flow cytometry and confocal microscopy using CD30 antibody (Novus biologicals, NBP1 – 72175). We also examined a total of 21 ALK(+) NSCLC and 17 ALK(-) NSCLC patients whose formalin fixed paraffin embedded tumor were available for CD30 immunohistochemistry staining using CD30 antibody (DAKO, M075101, clone Ber-H2) on Ventana Medical Systems Benchmark Ultra Automated Immunostainer (Tucson, AZ). CD30 IHC positive is defined as staining in ≥ 10% tumor cells. Results: CD30 expression was detected at a similar level in all four different NSCLC cell lines by western blot. The CD30 staining in A549 and H1299 was mainly membranous, as demonstrated by confocal microscope and the flow cytometry analysis. We did not detect any CD30 expression by IHC in all 21 ALK(+) and 17 ALK(-) NSCLC tumors. Conclusions: Our in vitro studies showed positive CD30 expression in four different NSCLC cell lines, but no significant CD30 expression was detected by IHC in both ALK(+) and ALK(-) NSCLC tumors. CD30 is unlikely a treatment target in NSCLC with or without ALK gene rearrangement.