Changes in tumour biological markers during primary systemic chemotherapy (PST).

BACKGROUND

The influence of primary systemic therapy (PST) on the expression of relevant therapeutic markers is still under investigation.

PATIENTS AND METHODS

Corresponding "baseline" biopsies and post-chemotherapy surgical specimens from 87 patients treated with neoadjuvant anthracycline- or taxane-based chemotherapy were analysed for the expression of the oestrogen receptor (ER), the progesterone receptor (PR), the B-cell lymphoma protein 2 (Bcl-2), the v-erb-b2 erythroblastic leukemia viral oncogene homolog 2 (Her2/neu), the tumour protein p53 and the proliferation-related Ki-67 antigen.

RESULTS

The pathological response rate was 70%. Twenty-three tumours (26%) changed hormone receptor classification after chemotherapy (7, ER; 16 PR). A significant change was also observed for Her2/neu status. Eleven tumours which were positive prior to PST down-regulated Her2/neu after chemotherapy. The median Ki-67 index decreased from 30% before to 13% after treatment (p<0.01). Minor changes were observed in the expression of Bcl-2 and p53 (9%). Only the reduction of Ki-67 was associated with pathological response to PST.

CONCLUSION

Her2/neu status as well as ER and PR status should be re-evaluated on post-chemotherapy surgical specimens since changes can be observed.