Background: Heat-shock protein 90 (HSP90) is an abundant protein in mammalian cells. It interacts with a variety of proteins that play key roles in breast neoplasia. This is the first study to assess serum levels of HSP90 in atypical ductal hyperplasia (ADH), lobular neoplasia (LN), ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC) and infiltrative lobular carcinoma (ILC).
Patients and methods: Serum concentrations of HSP90 in women with benign (n=34), ADH (n=26), DCIS (n=30), IDC (n=29), LN (n=20) and ILC (n=9) lesions were determined with immunoenzymatic assays. For the evaluation of serum concentrations along the transition from benign through precursor and preinvasive to invasive lesion, the severity of diagnosis was treated as an ordinal variable.
Results: No significant association was demonstrated between serum HSP90 levels and the severity of the lesion in ductal and lobular series. The post hoc comparison between the lobular and ductal precursor lesions (i.e. ADH vs. LN) did not yield a statistically significant difference. Similarly, the post hoc comparison between the lobular and ductal invasive carcinomas (i.e. IDC vs. ILC) did not point to a statistically significant difference.
Conclusion: This is the first study evaluating HSP90 serum levels in both lobular and ductal lesions of the breast. Contrary to published pathological findings according to which HSP90 exhibits significant variability along both series, such a finding was not replicated for the level of serum HSP90 concentrations.