HSP90AB1 and lung cancer: As shown in Table 3, the level of Hsp90-beta in MPE and serum of lung cancer patients with lymphatic invasion of N3 (2.09 ± 0.22 ng/mL in MPE; 1.46 ± 0.17 ng/mL in serum) was significantly higher than that in patients with N2 (1.85 ± 0.14 ng/mL in MPE; 1.36 ± 0.21 ng/mL in serum) and N1 (1.82 ± 0.23 ng/mL in MPE; 1.33 ± 0.08 ng/mL in serum) (P < 0.001) (Fig. 2e and f).