Auto
-antibodies against L-myc oncogene products (L-Myc) in sera from lung cancer patients were examined using bacterially synthesized glutathione S-transferase (GST) L-Myc fusion proteins and Western blot analysis. The detection rate of anti-L-Myc antibodies in sera from lung cancer patients was I O%, while that in sera obtained from normal volunteers was 0%. Five patients with non-small-cell lung cancers (2 adenocarcinomas, 2 squamous-cell carcinomas and I large-cell carcinoma) were included in the group with anti-L-Myc antibodies. These autoantibodies belonged to the IgG class and recognized the carboxy terminus of L-Myc. Circulating L-Myc was not detected in sera from patients with anti-L-Myc antibodies. Differences in age, sex, performance status, histology, stage, smoking history and prior treatment were not significantly different between anti-L-Myc antibody-positive and antibody-negative patients. Anti-nuclear antibodies were detected in 40% of lung cancer patients and 57% of those with anti-L-Myc antibodies. Our data suggest that detection of anti-L-Myc antibodies may be helpful in the diagnosis and evaluation of the host-immune response to L-Myc in a subset of lung cancer patients. o 1996 Wilq-Lis, Inc. The L-myc gene, located on chromosome 1p32, is a human oncogene with structural homology to c-myc and N-myc (Nau et al.. 1985; Kaye et al., 1988). L-myc is known to be amplified, or over-expressed, in 10-40% of tumors with neuroendocrine characteristics, such as small-cell lung cancer (SCLC). Overexpression of L-myc also has been reported in cases of non-small-cell lung cancer (NSCLC) (Shiraishi et al., 1989). L-inyc is recognized as an oncogene because it possesses transforming activity against rat embryo fibroblasts with activated ras in vitro (Birrer et al., 1988). L-myc is also important in controlling normal mammalian development, particularly in the brain, kidney and lung, and is thought to play a role in differentiation and proliferation in cooperation with c-myc and N-myc (Zimmerman et al., 1986; Bernard et al., 1992).
The immune response against the products of oncogenes and tumor-suppressor genes is important with respect to diagnosis and gene therapy for cancer. To date, the products of these genes have been evaluated using biopsy and surgical specimens, which are not suitable for patients with advanced disease. Serum auto-antibodies against the products of these genes, such as c-myc (Ben-Mahrez et al., 1990), c-myb (Soro-