PURPOSE: alphaB-crystallin, a small heat shock protein, is an anti-apoptotic protein associated with aggressive tumor behavior. A recent study revealed that alphaB-crystallin is overexpressed in a metastatic variant of the GI101A human breast carcinoma cell line. The purpose of this study was to investigate whether alphaB-crystallin is related to other breast tumor markers and can predict a breast cancer prognosis. METHODS: Eighty-two patients who underwent breast cancer surgery at Hallym Sacred Heart Hospital were enrolled. alphaB-crystallin expression was determined by immunohistochemical staining. Estrogen receptor, progesterone receptor (PR), human epidermal growth factor receptor, lymphovascular invasion, histological grade, other tumor markers and time to recurrence were compared with alphaB-crystallin expression. RESULTS: alphaB-crystallin expression in breast cancer tissues was associated with PR (p=0.030), the number of metastatic lymph nodes (pN) (p=0.020), lymphovascular invasion (p=0.022), histological grade (p=0.004) and triple negative breast cancer (TNBC) (p=0.004). alphaB-crystallin expression significantly decreased time to recurrence (p=0.039). CONCLUSION: The results revealed a strong relationship between alphaB-crystallin and poor prognostic factors such as the number of metastatic lymph nodes (especially pN2), TNBC, and rapid time to recurrence. We believe that alphaB-crystallin could be a novel oncoprotein biomarker of a poor prognosis in breast cancer.