Evaluation of c-erbB-2 overexpression and Her-2/neu gene copy number heterogeneity in Barrett's adenocarcinoma

Amplification of the Her-2/neu gene is accompanied by overexpression of its cell surface receptor product, c-erbB-2 protein. To investigate the degree of intratumoural heterogeneity we applied immunohistochemistry in primary Barrett's adenocarcinoma (BCA) (n = 6) and dysplasia adjacent to the carcinoma (n = 4). In addition, fluorescence in situ hybridisation (FISH) was performed in primary BCA (n = 5) and dysplastic areas (n = 4). For an objective evaluation digital image analysis and laser scanning microscopy were used. Five of six BCA showed a marked intratumoral heterogeneous staining pattern ranging from areas in which the tumour cells were negative or faintly positive to tumour areas with a strong staining of the entire membrane. Among the two dysplastic areas also a heterogeneous staining pattern was observed. FISH analysis revealed marked heterogeneity of intratumoral gene copy number changes in all BCA showing populations with different fractions of cells with polysomy, low level amplification and high level amplification. One dysplasia showed a minor population with Her-2/neu signal clusters. In conclusion, we observed marked intratumoural heterogeneity of c-erbB-2 protein overexpression and Her-2/neu gene copy number in the majority of the primary BCA analyzed. Digital image analysis and laser scanning microscopy were helpful in quantifying the variations in protein expression and DNA copy number in individual tumour cells. The observed heterogeneity could hamper the exact diagnostic determination of the c-erbB-2 status in small biopsies and possibly influence the effectiveness of a potential c-erbB-2 targeting therapy. Figures on http://www.esacp.org/acp/2000/20-1/walch.htm+ ++.

Clinicopathological characteristics of primary breast cancer in older geriatric women: a study of 39 Japanese patients over 80 years old

The number of primary breast cancers occurring in elderly women is increasing in Japan. Optimization of treatment regimens in this age group requires precise evaluation of the biological aggressiveness of these tumors as well as the performance status and extent of tumor spread. In 39 breast cancer patients who were at least 80 years old, we examined several parameters; the form of surgical therapy, the lymph node status, presence or absence of distant metastases, the histological type and grade of atypia, and overexpression of the c-erbB-2 oncoprotein in the cancer cells. They were correlated with the clinical outcome of the patient. Of the 33 patients who underwent a mastectomy and axillary lymph node dissection, five died from cancer recurrence. Only one out of 22 patients without lymph node metastases died from cancer, while four out of the eight patients with metastases to three or more lymph nodes died from cancer recurrence within 2.7 years of surgery. The overall survival curves also differed between patients with low-risk histological tumors or grade 1 or 2 invasive ductal carcinoma and those with grade 3 invasive ductal/lobular carcinoma. Overexpression of c-erbB-2 also affected survival. Regional recurrence occurred in three out of the six patients for whom only lumpectomy or simple mastectomy was performed. These results indicate that, although primary breast cancer occurring in patients over 80 years old was largely of low-grade malignancy, patients with three or more lymph node metastases, invasive ductal/lobular carcinomas of grade 3, or c-erbB-2 overexpression frequently exhibited an aggressive clinical course.

Determination of c-erbB-2 protein in primary breast cancer tissue extract using an enzyme immunoassay

The c-erbB-2 protein in breast cancer tissue extract was determined by using an enzyme-immunoassay (EIA) to see whether the quantitative determination of the oncoprotein correlates with the results of immunohistochemistry and other prognostic factors. Primary breast cancer from 104 patients was assayed for c-erbB-2 protein with an EIA that used two monoclonal antibodies directed against the extracellular domain of the protein. Pelleted tissue homogenate prepared routinely for hormone receptor assay was used as the starting material. The mean quantity of c-erbB-2 protein was 695 unit/mg protein (range 23 to 5939), and this correlated well with the results of immunohistochemical staining (P < 0.00001). It was found that 17.3% (18/104) of all tumors contained amounts of c-erbB-2 protein exceeding 1000 units/mg protein. All tumors with negative or weakly positive staining contained the oncoprotein as less than 1000 units/mg protein. The content of c-erbB-2 protein was correlated with the histologic grade (P = 0.0022), mitotic index (P = 0.0002) and degree of nuclear atypia (P = 0.013). It was inversely correlated with progesterone receptor (P = 0.006) and less strongly with estrogen receptor status (P = 0.016). Values of hormone receptor concentration and c-erbB-2 protein content showed a hyperbolic relationship that suggested biological interactions between c-erbB-2 protein and steroid hormone receptors. We conclude that c-erbB-2 protein in tissue extracts of primary breast cancer can be determined reliably by EIA, and it seems feasible to explore further the advantages of introducing EIA as a routine laboratory examination for providing additional information about the biological aspects of breast cancer.