Determination of threshold values for determining the size of the fraction of steroid hormone receptor-positive tumor cells in paraffin-embedded breast carcinomas

Abstract

Results: The first step in this process resulted in an previous publication where 20% of steroid hormone receptor-positive cells seemed to be an acceptable cutoff point for positivity. However, the second step provided the best correlation at approximately 35% of ER reactive cells in the cytokeratin-positive cell population. With this cutoff, the distribution of combined ER/PR profiles in our patient population of node-negative breast cancers also showed a distribution similar to the data from the SEER study. The fourth step, using the 35% threshold value, resulted in a good correlation (r ‫؍‬ 0.85, P < 0.0001) for ER and PR between IHC and MP-FCM in the 180 tumors investigated.Conclusion: By comparing in-house data with those from large external data collections in the literature, a threshold percentage can be defined that distinguishes steroid hormone receptor-negative from hormone receptor-positive tumors. As a result, information about DNA content and cell cycle distribution can be obtained. This observational study provides additional support to our opinion that MP-FCM is an alternative for IHC determination of ER and PR positivity. It is more objective and quantification can be done more appropriately. The additional value of this approach is that we generate continuous variables of ER/PR content instead of categorical classes, which can be used at different threshold levels for evaluation of clinical relevance. INTRODUCTIONThe value of steroid hormone receptor analysis in the management of patients with breast cancer has been demonstrated. Patients with estrogen receptor-positive (ER ϩ ) tumors have a longer disease-free interval and better survival (1,2) than those with ER Ϫ cancers. In addition, these patients are more likely to respond to endocrine therapies (3-5).Historically, biochemical assays such as the dextrancoated charcoal were regarded as the gold standard in receptor quantitation. This technique, which is based on homogenization of tissue, is not suitable for assessment of hormone receptors in small tumors and cells obtained by fine-needle aspiration biopsy. This technique also does not provide information regarding tumor heterogeneity for steroid hormone receptor. With the development of specific monoclonal antibodies, receptor status of a breast tumor is currently commonly established by an immunohistochemical (IHC) assay. These assays have the advantage of being applicable on routinely processed formalinfixed, paraffin-embedded tissue. Further, it allows only tumor cells to be assessed for receptor status (6,7). Despite this advantage, a lack of adequate standardization and quantitation remain as the most important limiting factor of that approach. The reported intralaboratory variation in the results reflects the existing differences in the way the procedure is being performed and interpreted by the histopathologist (8 -10).We previously described a multiparameter flow cytometric (MP-FCM) technique for the quantification of steroid hormone receptors in the epithelial compartment of forma...

Oridonin induces Mdm2‐p60 to promote p53‐mediated apoptosis and cell cycle arrest in neuroblastoma

“…For preparing single‐cell suspension, the technique described in a previous report was used . The cell density of the cell suspension was about 2 × 10 7 mL −1 .…”

“…For preparing single-cell suspension, the technique described in a previous report was used. 29 The cell density of the cell suspension was about 2 × 10 7 mL −1 . About 50-100 μL cell suspension was put onto each polylysine-coated section and was gently smeared with a clean section.…”

The analysis of quantitative expression of somatostatin and dopamine receptors in gastro-entero-pancreatic tumours opens new therapeutic strategies

“…sst level expression and in particular sst2 may predict clinical response to somatostatin receptor analogues and could thus help in tailoring targeted therapy as shown in somatotroph adenomas (37,24). As in patients with breast cancer where oestrogen receptor status and levels help in predicting therapeutic responses, quantitative receptor measurements may help in determining responses to cold and radiolabelled somatostatin (or somatostatin-dopamine) analogues to be used in treatment according to analogues binding characteristics (38,39).…”