Quantitation of HER-2/neu oncoprotein overexpression in invasive breast cancer by image analysis: a study comparing fresh and paraffin-embedded material.
HER-2/neu oncoprotein overexpression was compared in fresh frozen and paraffin-embedded formalin-fixed invasive breast cancer material from the same patients. The HER-2/neu protein was detected by an immunohistochemical staining method, and the average amount of protein staining per cell was measured using the CAS-200 image analysis system and expressed relative to the amount of HER-2/neu protein of calibration cells of the SKBR3 cell line which are known to have amplification of the HER-2/neu gene and overexpression of the HER-2/neu protein. There was a significant correlation between degree of HER-2/neu protein overexpression and DNA-hyperdiploidy (P less than 0.01, chi 2 test). No significant correlation could be demonstrated between degree of HER-2/neu overexpression and tumor size, lymph node status, number of positive nodes or morphometric features. There was in general a good concordance (r = 0.83) in HER-2/neu expression values between fresh and paraffin-embedded material. Pairwise comparison of the two series (Wilcoxon signed ranks test) revealed no significant differences, indicating that there were no systematic differences between HER-2/neu assessments in fresh and paraffin material. When analysing the HER-2/neu expression values according to thresholds used earlier for overexpression, comparable results for fresh and paraffin material were obtained for most cases. In the fresh and paraffin material a different staining pattern was observed (more membrane staining in the fresh material in contrast to a more diffuse staining pattern in the paraffin material). It was concluded that both fresh-frozen and paraffin-embedded, formalin-fixed material is suitable for assessment of HER-2/neu protein overexpression by image analysis and provides comparable HER-2/neu expression values in most cases.(ABSTRACT TRUNCATED AT 250 WORDS)
van Diest
P J
PJ
Department of Pathology, Free University Hospital, Amsterdam, The Netherlands.
Baak
J P
JP
Chin
D
D
Theeuwes
J W
JW
Bacus
S S
SS
D001943:Breast Neoplasms / Q000737:chemistry / Q000473:pathology*; D004247:DNA / Q000032:analysis; D005260:Female; D005629:Frozen Sections; D015870:Gene Expression; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D009361:Neoplasm Invasiveness / Q000473:pathology; D009856:Oncogene Proteins, Viral / Q000032:analysis* / Q000235:genetics; D011003:Ploidies; D018719:Erb-b2 Receptor Tyrosine Kinases; D014021:Tissue Preservation / Q000379:methods
D004247:DNA; D009856:Oncogene Proteins, Viral; D018719:Erb-b2 Receptor Tyrosine Kinases