Heat shock protein 27 overexpression in breast cancer lymph node metastasis

Background: Heat shock protein 27 (hsp-27) is overexpressed in 67% pure ductal carcinoma in situ (DCIS), in 50% DCIS associated with invasive ductal carcinoma (IDC), and in 25% IDC alone. If this decrease in hsp-27 expression has a role in the progression of malignancy in IDC, we postulate a further reduction in expression in nodal metastasis.Methods: To test this hypothesis, we evaluated the distribution of hsp-27 in primary IDC and in synchronous regional lymph node metastasis within the same patient by immunohistochemistry.Results: Nine of 30 primary IDCs (30%) and 22 of 30 lymph node metastases (73%) overexpressed hsp-27. Contrary to our hypothesis, of 21 IDCs with no or low hsp-27 expression, 13 (62%) had overexpression of this protein within nodal metastasis.Conclusions: hsp-27 appears to confer cytoprotection for metastatic cells, which may help explain why hsp-27 overexpression is associated with reduced disease-free survival in breast carcinomas.