Background Surgery is the treatment of choice for early and for some locally advanced non-small cell lung cancer (NSCLC). Ipsilateral hilar and mediastinal lymph nodes are generally removed at the time of tumor resection. There is now increased awareness about the physiological role of lymph nodes in cancer. We investigated the expression profiles of immune-related markers in matched tumor tissue, affected and unaffected N1 and N2 lymph nodes in patients with NSCLC and their relation to survival.

Materials and Methods Internal hospital databases were screened for surgically-treated NSCLC patients with documented relapse or long-term disease-free survival (defined as 3 years). Data on patients’ age, sex, surgery, (neo)adjuvant therapy, tumor characteristics and time and location of relapse was extracted. FFPE tissue blocks of primary tumor, affected and unaffected lymph nodes were collected. mRNA was extracted from these tissues and expression profiling of 751 immune-related genes was performed using the PanCancer IO 360 panel by NanoString Technologies. Results

A total of 754 NSCLC patients were screened. Of these, 71 patients showed long-term disease-free survival and 80 patients had local or systemic relapse within 3 years after surgery. Expression profiles of immune-related genes in tumor and lymph node immune populations differed between patients with and without 3-year disease-free survival.

Conclusions Expression profiles of immune-related genes differ between patients with and without relapse. Our findings show that differences in expression profiles of immune-related genes in tumor and lymph nodes should be taken into account when assessing patient prognosis.

Disclosure Information L. Sellmer: None. J. Kovács: None. J. Kumbrink: None. J. Neumann: None. J. Walter: None. D. Kauffmann-Guerrero: None. C. Schneider: None. A. Tufman: None.