Our goal was to specifically render tumor cells susceptible to natural cytolytic anti-alphaGal antibodies by using a murine alpha1,3galactosyltransferase (malphaGalT) transgene driven by a designed form of HER2/neu promoter (pNeu), the transcription of which is frequently observed to be above basal in breast tumors.
We studied effects on differentiation and cell death of erbB-2/neu during mammary-gland development in transgenic mice expressing an activated, oncogenic rat erbB-2/neu gene controlled by the mammary-gland-specific promoter from mouse-mammary-tumor virus (MMTV-LTR).
Analysis of the breast tumor cell lines indicated that most of the cell lines had the following features: they were derived from large tumors with or without axillary node metastases; were aneuploid and exhibited a moderate to poorly differentiated phenotype; were estrogen receptor (ER)- and progesterone receptor (PR)-negative; and overexpressed p53 and HER2/neu proteins.
We examined 86 primary formalin-fixed, paraffin-embedded breast tumors for overexpression of EGFR and NEU and correlated our findings with the presence of cell surface phosphotyrosine as an indicator of tyrosine kinase activity at the plasma membrane.
To investigate whether overexpression of the neu protein in breast tumors differentiates risk factor patterns for breast cancer, neu protein overexpression was determined in 296 breast carcinomas of patients participating in an ongoing population-based case-control study.