Predictive Value of the Pattern of β-Catenin Expression for Pathological Response to Neoadjuvant Chemotherapy in...

This study aimed to explore the association of β-catenin expression pattern with pathological response after neoadjuvant chemotherapy in breast cancer (BC) patients.

In this retrospective exploratory study, data for 50 BC patients who received neoadjuvant chemotherapy were recorded. β-catenin expression in tumours was assessed using immunohistochemistry and classified as either membranous or cytoplasmic according to the pattern of staining. Distributions of different clinico-pathological parameters according to β-catenin expression were assessed using the Chi-square test. Logistic regression analysis was used to assess any relation of the pattern of β-catenin expression with the pathological response.

Cytoplasmic β-catenin expression was detected in 34% of BCs. Among our cases, 52% were hormonal receptor (HR)-positive, 24% were HER2-positive, 74% were clinical stage III and 74% received both anthracycline and taxane-based chemotherapy. Patients with cytoplasmic expression were more commonly younger than 40 years at diagnosis (cytoplasmic, 41.2% vs. no cytoplasmic expression, 12.1%, p=0.03). By doing t-test, cytoplasmic β-catenin expression was linked with a higher body mass index compared to membranous-only expression (mean± SD 33.0 ± 4.47 vs. 29.6 ±6.01, respectively, p=0.046). No significant associations were found between β-catenin expression and other parameters such as HR and HER2 status, or clinical stage. Complete pathological response (pCR) rate was twice as great in patients with membranous expression but without statistical signi cance (membranous- only, 33.3% vs. cytoplasmic, 17.6%, OR=2.3, 95% CI= 0.55-9.87, p=0.24).

This study suggests that cytoplasmic β-catenin expression may be linked with lower probability of achieving pCR after neoadjuvant chemotherapy. These data need to be validated in a larger cohort of patients.