The testing of HER2 on tumour samples The performed
according to the American Society for Clinical
Oncology and College of American Pathologists
(ASCO/CAP) recommendations [6]. The expression of
HER2 was initially scored using IHC. Score 0 and 1
tumours were considered ‘negative’ and score 3 tumours
were considered ‘positive’ on the basis of protein
expression alone. Score 2 samples were further investigated
using ISH, either fluorescent in situ hybridisation
(FISH) before 2009 or silver-enhanced in situ hybridisation
(SISH) thereafter [