Background: Heat shock protein beta-1 (HspB1) is a chaperone of the sHsp (small heat shock protein). The common functions of sHsps are chaperone activity, inhibition of apoptosis, regulation of cell development, and cell differentiation, take part in signal transduction.
Objective: To study the intracellular localization of phosphorylated features and non-phosphorylated forms of HspB1 in primary breast cancer cells and to evaluate their relationship with regional lymphatic metastasis.
Material and methods: Tumor biopsies of breast tissue were collected from 100 patients with a confirmed diagnosis of invasive carcinoma, nonspecific type, between the ages of 31-80 years. Immunohistochemistry was used to determine the intracellular localization of phosphorylated and non-phosphorylated forms of HspB1.
Results: The result of this study showed that biopsies from patients with lymph node metastasis exhibited significantly higher levels of phosphorylated forms of HspB1 in the nucleus and cytoplasm compared with the group without lymph node metastasis. Analysis showed that the expression of phosphorylated forms of the chaperone HspB1 correlates with the amount and percentage of lymph node metastases affected.
Conclusion: The nuclear expression of phosphorylated and non-phosphorylated forms of the chaperone HspB1 is a marker of tumor cells associated with lymphatic metastasis of breast cancer.
Keywords: Breast cancer; heat shock protein beta-1 (HspB1); immunohistochemistry; lymph node metastases; prognostic markers.