RSPO2 and non-small cell lung carcinoma: In NSCLC patients without metastasis to lymph nodes (N0 feature), olfactory receptor 2AT4 and R-spondin-2 were detected in all samples (100%); however, these proteins were also observed in 67% and 50% of the samples of patients with the N1 feature, respectively, and were also detected in 75% of the samples of patients with the N2 feature (Table S6).