STYK1 expression in breast cancer and its association with vascular invasion and clinicopathological features.

Vascular invasion (VI) is an essential step in the progression of breast cancer (BC) and is a key factor behind morbidity and mortality. In a previous work using gene expression profiling, upregulation of STYK1 was one of the genetic changes that was found associated with VI. The aims of the following study were to assess (1) level and pattern of STYK1 expression in BC tissues and (2) its association with clinicopathological features and with patient outcome. Histopathological, clinical data and 10‒year survival data for 220 primary breast carcinoma was retrieved. From each specimen, one representative formalin-fixed paraffin-embedded tissue section was stained by immunohistochemistry (IHC) with STYK1 antibodies. IHC score was calculated and correlated with clinicopathological features of tumors. Higher STYK1 expression was detected in invasive BC compared with normal and non-invasive tumors, P = 0.001 and was significantly associated with the presence of vascular invasion (P = <0.001), lymph node metastasis (P = 0.032) estrogen receptor positivity (P = 0.033), non‒triple negative phenotype (P = <0.018) and occurrence of locoregional recurrence (P = 0.011). No association was detected with other tumor features such as tumor size, grade, development of distant metastasis or overall survival. STYK1 is expressed at a higher level in invasive BC compared with non-cancerous tissues. This high expression is significantly associated with presence of VI, LN metastasis and occurrence of recurrence. These findings suggest that STYK1 could be a possible molecular target for breast carcinoma. Targeted therapy that can inhibit STYK1 kinase can be a possible approach for the development of novel therapies in breast carcinoma.