Finite proliferative lifespan in vitro of a human breast cancer cell strain isolated from a metastatic lymph node

We recently described culture conditions that allow proliferation of metastatic human breast cancer cells from biopsy specimens of certain patient samples. These conditions resulted in the development of an immortalized cell strain designated SUM-44PE. These same culture conditions were used to isolate a human breast cancer cell strain from a metastatic lymph node of a separate breast cancer patient. The SUM-16LN human breast cancer cells isolated from this specimen were cultured either in serum-free medium or serum-containing medium supplemented with insulin and hydrocortisone. Unlike the SUM-44PE cells that have proliferated in culture continuously for over two years, SUM-16LN cells proliferated in culture for approximately 200 days and underwent 15 to 20 population doublings before undergoing cell senescence. No cells of this strain proliferated beyond passage 8. SUM-16LN cells were keratin-19 positive and had an aneuploid karyotype. These cells overexpressed p53 protein and had an amplified epidermal growth factor (EGF) receptor gene that resulted in high level expression of tyrosine phosphorylated EGF receptor protein. Despite the presence of high levels of tyrosine phosphorylated EGF receptor in these cells, they proliferated in serum-free, EGF-free medium and did not secrete detectable levels of EGF-like mitogenic growth factor. In addition, these cells were potently growth inhibited by all concentrations of exogenous EGF tested and by the neutralizing EGF receptor antibody Mab 425. These results suggest that the high level of tyrosine phosphorylated EGF receptor present in these cells is the direct result of receptor overexpression and not the result of the presence of a simulatory ligand. Thus, SUM-16LN represents a human breast cancer cell strain that exhibited genetic and cellular characteristics of advanced human breast cancer cells. Nevertheless, these cells exhibited a finite proliferative lifespan in culture, suggesting that cellular immortalization is not a phenotype expressed by all human breast cancer cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44199/1/10549_2004_Article_BF00666588.pd

HER-2/neu gene amplification in esophageal adenocarcinoma and its influence on survival

The original publication is available at the Annals website at www.springerlink.com/content/1534-4681.Background: HER-2/neu (c-erbB-2, HER2) gene amplification and protein overexpression have been associated with poor prognosis in several solid tumors, including breast and gastric cancer. Its incidence and significance in esophageal adenocarcinoma is unknown. Materials and Methods: Tissue microarrays were successfully constructed from 89 paraffin-embedded archival specimens of esophageal adenocarcinomas for HER2 gene amplification by silver-enhanced in situ hybridization (SISH). No patients had undergone neoadjuvant therapy. Protein overexpression was tested with immunohistochemistry (IHC) using automated immunostaining (Ventana Benchmark). Incidence of HER2 positivity, correlation to clinicopathological variables in esophageal cancer patients, and concordance between SISH and IHC were determined. Results: True HER2 gene amplification was detected in 14 esophageal cancer specimens (16%), and 92% of those with high-level HER2 amplification showed positive HER2 protein overexpression. No significant associations were found among gene amplification and clinicopathological factors. The 5-year survival rates were 57% for esophageal cancer patients with HER2 amplification compared with 32% without, but the difference in overall survival was not significant (P = .37). The correlation between SISH and IHC was statistically significant (P < .0001). Conclusion: While molecular targeting may be possible for approximately 16% of esophageal adenocarcinoma patients, HER2 oncogene amplification did not influence survival in this study.Sarah K. Thompson, Thomas R. Sullivan, Ruth Davies and Andrew R. Ruszkiewic