Analysis of the HER2/neu gene amplification in microdissected breast cancer tumour samples.

The HER2/neu oncogene has been reported to be amplified in > 20% of invasive ductal carcinomas. In order to investigate the HER2/neu status in pure populations of breast cancer cells, a laser capture microdissection (LCM) system was used. Formalin-fixed paraffin-embedded breast tissue areas corresponding to normal ducts, ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) were microdissected and genomic DNA was isolated by a modified proteinase K- phenol extraction method and subjected to PCR for HER2/neu analysis. One hundred % concordance for detection of the HER2/neu gene amplification was found between immunohistochemistry and PCR used in combination with LCM. Our results indicated that LCM is a powerful technique for isolating pure populations of cells from paraffin-embedded tissue sections and that these cells can be used to study genomic alterations at the DNA level.