DNA amplification on chromosome 20q13 is commonly detected in breast carcinoma and is correlated with poor prognosis. STK15 maps to this amplicon. The objective of the current study was to use immunohistochemistry to determine STK15 expression in primary breast tumors. The authors also explored whether STK15 was a prognostic factor for breast carcinoma by comparing the level of STK15 gene expression with clinical parameters that are known prognostic factors for the disease.
Archival mastectomy and lumpectomy specimens, randomly selected, were immunohistochemically stained to determine the STK15 gene expression level. The clinical parameters of these same patients were reviewed retrospectively and analyzed for correlations with STK15 expression level, based on a positive-versus-negative scoring system.
Of the 112 human breast tumor specimens analyzed, 26% stained positively for STK15 by immunohistochemistry. Of the tumors, that stained positively 62.1% had a well-to-moderately differentiated nuclear grade. The correlation between STK15 staining and nuclear grade was nearly statistically significant (P = 0.05). No association was found between STK15 staining and tumor size, lymph node status, or hormone receptor status. Analysis of recurrence-free survival and overall survival rates also failed to reveal a statistically significant difference between the two groups.
STK15 expression by immunohistochemistry was noted in approximately one-fourth of primary breast tumors. STK15 expression was associated with nuclear grade, but no correlation was found between the other clinical parameters evaluated. Furthermore, no differences were found in survival rates when they were analyzed by level of STK15 staining. Cancer 2004;100:12-9. ? 2003 American Cancer Society.