Protein and gene expression of estrogen receptor alpha and nuclear morphology of two breast cancer cell lines after different fixation methods

We assessed morphology and ER alpha protein and gene expression of two breast cancer cell lines after three different fixatives: neutral-buffered 10% formaldehyde, LN-FIX and FineFIX and varying fixation times. We found that the cell morphology was best preserved in cells fixed with LN-FIX. Two commercial fixatives used in this study shrank cells less than formalin. In immunohistochemical assay samples were stained with two different ERa antibodies, clone 1DS and clone SP1. All tested fixatives were suitable for immunohistochemistry. Staining was more intensive and the number of stained cells was larger with the clone 105 than with the clone SPI. Our gene expression analysis showed that formalin and LN-FIX preserve the ER alpha better than FineFIX, which is advertised to be optimal for molecular analysis. Our study suggests that tissues fixed with formalin are suitable also for molecular biology assays. This makes possible to research formalin-fixed paraffin-embedded archival tissues also with molecular techniques. (C) 2009 Elsevier Inc. All rights reserved.