HSP90AB1 and lung cancer: As shown in Table 3, whether in MPE or serum, patients with undifferentiated (2.03 ± 0.10 ng/mL in MPE; 1.44 ± 0.12 ng/mL in serum) and poorly undifferentiated (2.12 ± 0.07 ng/mL in MPE; 1.43 ± 0.17 ng/mL in serum) lung cancer showed an increased Hsp90-beta level compared with those of moderate (1.82 ± 0.13 ng/mL in MPE; 1.33 ± 0.16 ng/mL in serum) and well differentiation (1.80 ± 0.09 ng/mL in MPE; 1.36 ± 0.13 ng/mL in serum) (P < 0.001) (Fig. 2a and b).