HER2-positive breast cancer is characterized by aggressive growth and poor 
prognosis. Women with metastatic breast cancer with over-expression of HER2 
protein or excessive presence of HER2 gene copies are potential candidates for 
Herceptin (Trastuzumab) targeted treatment that binds to HER2 receptors on tumor 
cells and inhibits tumor cell growth. Fluorescence in situ hybridization (FISH) 
is one of the most widely used methods to determine HER2 status. Typically, 
evaluation of FISH images involves manual counting of FISH signals in multiple 
images, a time consuming and error prone procedure. Recently, we developed novel 
software for the automated evaluation of FISH images and, in this study, we 
present the first testing of this software on images from two separate research 
clinics. To our knowledge, this is the first concurrent evaluation of any FISH 
image analysis software in two different clinics. The evaluation shows that the 
developed FISH image analysis software can accelerate evaluation of HER2 status 
in most breast cancer cases.