ABSTRACT
SUMMARY
OBJECTIVE:
Breast cancer is the most common
malignancy in
women. In the
treatment of these
patients, pathological complete response is defined as the absence of invasive
cancer in
breast or
lymph node tissue after the completion of
neoadjuvant chemotherapy. In this study, we aimed to investigate the relationship of
enhancer of zeste homolog 2 and
mucin 1 expressions with pathological complete response in
patients with
breast cancer receiving
neoadjuvant chemotherapy.
METHODS:
A total of 151
patients were included in the study.
Enhancer of zeste homolog 2 and
mucin 1 expressions were evaluated in the
biopsy materials pre-
neoadjuvant chemotherapy and post-
neoadjuvant chemotherapy surgical material, and their relationship with pathological complete response was investigated.
RESULTS:
The pathological complete response rates were significantly higher among the
hormone receptor-negative
patients, those with a high Ki-67 score, and
patients with HER2-positive. Higher pathological complete response rates were obtained from
patients with
enhancer of zeste homolog 2 expression positivity pre-
neoadjuvant chemotherapy. In addition, after
neoadjuvant chemotherapy,
enhancer of zeste homolog 2 expression was found to be completely negative in materials with pathological complete response; that is, in
breast tissues considered to be
tumor-free. While there was no significant relationship between
mucin 1 expression and pathological complete response pre-
neoadjuvant chemotherapy,
mucin 1 expression was determined to significantly differ between the
tissues with and without pathological complete response among the surgical materials examined.
CONCLUSION:
In our study investigating the relationship between
enhancer of zeste homolog 2 and
mucin 1 expression and pathological complete response in
patients who received
neoadjuvant chemotherapy, we found that
enhancer of zeste homolog 2 expression could be used as a predictive marker for pathological complete response. However,
mucin 1 expression was not associated with pathological complete response.