At the group level, serum PAK6 levels in patients with SCLC (56.44 ng/L) were significantly higher than in those with NSCLC (41.06 ng/L), PN (37.82 ng/L), and the NC group (34.75 ng/L) (p < 0.01, Fig. 1A). Here, PAK6 is linked to small cell lung carcinoma.