HSP90AB1 and cancer: In malignant tumours, a significant increase of Hsp27 (P < 0.01), Hsp72 (P < 0.05) and Hsp90 (P < 0.01) expression, as well as a significant fall in Hsp73 (P < 0.01) immunoreactivity was noted compared to normal mammary gland (Figure 8).