The prognostic role of a phospho-Stathmin 1 signature in breast cancer treated with neoadjuvant chemotherapy.

Background: High expression of Stathmin 1 (STMN1) protein is related to a poor prognosis in various tumors, including breast cancer. In our previous study, a phospho-STMN1 signature was conducted to predict outcomes in adjuvantly treated breast cancer patients. This study aimed to explore the relationship of STMN1 expression with our phospho-STMN1 signature and the prognosis of patients treated with neoadjuvant chemotherapy (NACT).

Methods: A retrospective analysis of 116 patients who received NACT in The First Affiliated Hospital of Sun Yat-sen University between December 2008 and March 2016 was conducted. Patients were followed up through telephone once a year until 2022. The levels of STMN1, Ser16, Ser25, Ser38, and Ser63 phosphorylation and GRP78 expression in pre-NACT biopsy specimens from the patients were detected by immunohistochemistry. The recurrence risk score for each patient was calculated using the p-STMN1/GRP78 model. Clinical and pathological parameters, pathological complete response and objective response rates, and survival data were analyzed.

Results: In patients with NACT-treated breast cancer, high levels of STMN1, Ser25 phosphorylation, Ser38 phosphorylation, and GRP78 were related to worse disease-free survival (DFS), as was a high p-STMN1/GRP78 model risk score. In contrast, high Ser16 and Ser63 phosphorylation levels were related to better DFS [p-STMN1/GRP78 model: P=0.002, HR =0.180 (0.061-0.534); STMN1: P=0.001, HR =0.290 (0.147-0.572); Ser16: P=0.036, HR =2.019 (1.049-3.886); Ser25: P=0.013, HR =0.392 (0.188-0.819); Ser38: P=0.001, HR =0.293 (0.153-0.559); Ser63: P=0.006, HR =3.346 (1.407-7.961); GRP78: P=0.010, HR =0.417 (0.214-0.815)]. However, no significant statistical difference was found in the multivariate regression. The relationship between these markers and the therapeutic effect of NACT (pathological complete response and objective response) showed the same tendency with survival. The area under the receiver operating characteristic curve for the p-STMN1/GRP78 model was 0.790 (P=0.001) with sensitivity of 70% and specificity of 74%.

Conclusions: The expression and serine phosphorylation status of STMN1 may be beneficial as biomarkers for predicting the prognosis of breast cancer patients treated with NACT. Our p-STMN1/GRP78 model could become a widely applied signature for assessing the metastatic risk of breast cancer patients, potentially facilitating their individualized management before NACT.