HSP90AB1 and lung cancer: As shown in Table 3, the level of Hsp90-beta in MPE and serum of lung cancer patients at T4 stage (2.18 ± 0.19 ng/mL in MPE; 1.46 ± 0.15 ng/mL in serum) was significantly higher than that in patients at T3 stage (1.80 ± 0.13 ng/mL in MPE; 1.37 ± 0.13 ng/mL in serum) and T2 (1.81 ± 0.11 ng/mL in MPE; 1.35 ± 0.10 ng/mL in serum) (P = 0.009, = 0.013) (Fig. 2c and d).