Current and future approach to the pathologist's assessment for targeted therapy in breast cancer

COX-2 Expression in Breast Carcinoma with Correlation to Clinicopathological Parameters

Objective: Breast carcinoma is the most common malignant tumor and the leading cause of carcinoma deaths in women. Its etiology is multifactorial, implicating reproductive factors, hormonal imbalances and genetic predispositions. Studies have shown that Cycloxygenase-2 (COX-2) plays an important role in the carcinogenesis and increased expression has been regarded as a poor prognostic factor. The objective of our study is 1. To study COX-2 expression in normal breast tissue, DCIS and invasive breast cancer. 2. To determine COX-2 expression with clinicopathological prognostic parameters. Methods: Radical mastectomy specimens were studied for COX-2 expression by immunohistochemistry in 50 patients diagnosed as breast carcinoma. COX-2 expression is quantified as IHS Score and separately calculated for normal breast epithelium near the tumor, DCIS and invasive areas. Relationship between COX-2 expression with various clinicopathological parameters was evaluated. Result: The results of our study suggest an association of the expression of COX-2 to the factors associated with poor prognosis in breast cancer, such as larger tumor size, positive lymph node status, higher T stage and N stage and lymphovascular invasion. There was a higher COX-2 expression in the DCIS component as compared to the invasive ductal carcinoma component and the adjoining breast epithelium. Conclusion: Our study established the role of COX-2 in carcinogenesis and its association with adverse prognostic factors.

SLC35B2 expression is associated with a poor prognosis of invasive ductal breast carcinoma

BACKGROUND

Breast cancer is the most common malignancy in women worldwide, including Thailand, and is a major cause of mortality and morbidity, despite advances in diagnosis and treatment. Novel gene expression in breast cancer is a focus in searches for prognostic biomarkers and new therapeutic targets.

MATERIALS AND METHODS

The mRNA expression of novel B4GALT4, SLC35B2, and WDHD1 genes in breast cancer were examined in invasive ductal breast carcinoma (IDC) patients using quantitative real-time reverse transcription polymerase chain reaction (QRT-PCR).

RESULTS

Among these genes, increased expression of SLC35B2 mRNA was significantly associated with TNM stage III+IV of IDC (p<0.001). Hence, up-regulation of SLC35B2 may serve as a prognostic biomarker for poor prognosis, and is also a potential therapeutic target in breast cancer.

Quantitative assessment and classification of tissue-based biomarker expression with color content analysis

CONTEXT

The use of computer aids has been suggested as a way to reduce interobserver variability that is known to exist in the interpretation of immunohistochemical staining in pathology. Such computer aids should be automated in their usage but also they should be trained in an automated and reproducible fashion.

OBJECTIVE

To present a computer aid for the quantitative analysis of tissue-based biomarkers, based on color content analysis.

DESIGN

The developed system incorporates an automated algorithm to allow retraining based on the color properties of different training sets. The algorithm first generates a color palette containing the colors present in a training subset. Based on the palette, color histograms are derived and are used as feature vectors to a pattern recognition system, which returns an output proportional to biomarker continuous expression or a categorical classification. The method was evaluated on a database of HER2/neu digital breast cancer slides, for which expression scores from a pathologist panel were available. The system was retrained and evaluated on different transformations of the database, including compression, blurring, and changes in illumination, to examine its robustness to different imaging conditions frequently met in digital pathology.

RESULTS

Results showed high agreement between the results of the algorithm and the truth from the pathologist panel as well as robustness to image transformations.

CONCLUSIONS

The results of the study are encouraging for the potential of this method as a computer aid to assess biomarker expression in a consistent and reproducible manner.

Triple-negative and basal-like breast cancer: implications for oncologists

Since the start of the 1990s, molecular pathology has been playing an increasingly important role in cancer diagnosis and treatment.[...]

EGFR expression correlates with decreased disease-free survival in triple-negative breast cancer: a retrospective analysis based on a tissue microarray

The aim of this study was to analyze the prognostic value of EGFR expression for patients with triple-negative breast cancer (TNBC). Clinical data of these patients were collected and analyzed, and immunohistochemical staining for EGFR was performed on tissue microarrays of operable breast cancer from 287 patients with TNBC, who were treated at Sun Yat-sen University Cancer Center from January 1995 to December 2008. EGFR expression was found in 36.2% of the cases with TNBC. A significant correlation was found between EGFR expression and disease-free survival (DFS). Univariated analysis indicated that EGFR expression had a significant prognostic value in TNBC patients, whereas multivariate analysis indicated that EGFR was a significant independent prognostic factor of DFS (P = 0.011) in all patients. Our results suggested that EGFR was an independent prognostic factor of DFS in patients with TNBC. Therefore, EGFR could become a good therapeutic target in the treatment of TNBC.

Evolution in Endometrial Cancer: Evidence From an Immunohistochemical Study

Background:

It is poorly described how endometrial cancer biology changes during tumor evolution. We hypothesize that characterization of molecular targets in recurrent lesions is more relevant for targeting treatment.

Methods:

Paired biopsies from primary and recurrent endometrial cancer tumors (n = 85) were stained immunohistochemically for the following proteins: estrogen receptor (ER), progesterone receptor (PR), stathmin (correlating with phosphatidylinositol 3-kinase activity), HER-2/neu, WT1 (Wilms tumor gene 1), phospho-mammalian target of rapamycin (p-mTOR), and p53. Each tumor was scored, using a semiquantitative and subjective grading system. Discordance, a change in expression between primary and recurrent tumor, was defined as ≥2 step change; concordance was ≤1 step change. The frequency of change was correlated with established prognostic markers in endometrial cancer.

Results:

Fifty-six patients (67%) were diagnosed with endometrioid carcinoma, 23 (27%) with serous/clear cell carcinoma. A change in expression between primary and recurrent tumor was noted in 7% to 31% of patients for ER, PR, stathmin, HER-2/neu, WT1, p-mTOR, and p53. Concordant-positive cases for PR were significantly correlated with stage, tumor grade, and histological subtype. Expression of ER, p53, and p-mTOR in cytoplasm in the recurrent tumor correlated significantly with survival.

Conclusions:

Endometrial cancer biology changes over time. The decision on targeted treatment should preferably be based on recurrent tumor characteristics.

Confirmation of a low HER2 positivity rate of breast carcinomas - limitations of immunohistochemistry and in situ hybridization

Background

Accurate assessment of the human epidermal growth factor receptor 2 (HER2) of invasive breast cancer is essential to treatment decisions since the advent of targeted therapy with the humanized monoclonal antibody trastuzumab and the dual tyrosine kinase inhibitor lapatinib. In the literature, the percentage of HER2-overexpressed/amplified breast carcinomas range from 3% to 30%. The routinely assigned low rate of 9% of HER2-overexpressed breast carcinomas alarmed one of our gynecologists who requested to confirm our HER2 test results.

Methods

A small study of 83 patients with breast carcinoma was designed to reexamine the routinely assessed HER2 status using immunohistochemistry and fluorescence in situ hybridization.

Results

The low rate of 9% of HER2-overexpressed/amplified breast tumors (DIN1C-3, invasive carcinoma) could be confirmed. However, FISH revealed two false positive cases and one false negative case. Moreover a case with an equivocal result in FISH was detected.

Conclusion

The HER2 positivity rate may be as low as 9%. The novel ASCO/CAP criteria for assessing immunohistochemical results in HER 2 testing reduce the false positive rate of HER2. First-line testing with immunohistochemistry may obscure false positive and false negative test results. In heterogeneous carcinomas even fluorescence in situ hybridization may not succeed in a correct evaluation of HER2.

Classical and Novel Prognostic Markers for Breast Cancer and their Clinical Significance

The use of biomarkers ensures breast cancer patients receive optimal treatment. Established biomarkers such as estrogen receptor (ER) and progesterone receptor (PR) have been playing significant roles in the selection and management of patients for endocrine therapy. HER2 is a strong predictor of response to trastuzumab. Recently, the roles of ER as a negative and HER2 as a positive indicator for chemotherapy have been established. Ki67 has traditionally been recognized as a poor prognostic factor, but recent studies suggest that measurement of Ki67-positive cells during treatment will more effectively predict treatment efficacy for both anti-hormonal and chemotherapy. p53 mutations are found in 20–35% of human breast cancers and are associated with aggressive disease with poor clinical outcome when the DNA-binding domain is mutated. The utility of cyclin D1 as a predictor of breast cancer prognosis is controversial, but cyclin D1b overexpression is associated with poor prognosis. Likewise, overexpression of the low molecular weight form of cyclin E1 protein predicts poor prognosis. Breast cancers from BRCA1/2 carriers often show high nuclear grades, negativity to ER/PR/HER2, and p53 mutations, and thus, are associated with poor prognosis. The prognostic values of other molecular markers, such as p14^ARF, TBX2/3, VEGF in breast cancer are also discussed. Careful evaluation of these biomarkers with current treatment modality is required to determine whether their measurement or monitoring offer significant clinical benefits.

The influence of common polymorphisms on breast cancer

Breast cancer is one of the most frequently diagnosed cancers in the Western world and a significant cause of mortality worldwide. A small proportion of cases are accounted for by high-penetrance monogenic predisposition genes; however, this explains only a small fraction (less than 5%) of all breast cancers. Increasingly with advances in molecular technology and the development of large research consortia, the locations and identities of many low-penetrance genetic variants are being discovered. However, each variant has a very small effect similar to or smaller than many of the known environmental risk factors. It is therefore unlikely that these variants will be appropriate for predictive genetic testing, although they may identify novel pathways and genes which provide new insights and targets for therapeutic intervention. The future challenges will be identifying causal variants and determining how these low-penetrance alleles interact with each other and with environmental factors in order to usefully implement them in the practice of clinical medicine. Furthermore, it is clear that breast cancer comes in many forms with the tumour pathology and immunohistochemical profile already being used routinely as prognostic indicators and to inform treatment decisions. However, these indicators of prognosis are imperfect; two apparently identical tumours may have very different outcomes in different individuals. Inherited genetic variants may well be one of the other factors that need to be taken into account in assessing prognosis and planning treatment.

Evaluation of HER2 in breast cancer: reality and expectations

BACKGROUND

The introduction of drugs, whose mechanisms of action are directed against specific molecules involved in cancer initiation and/or progression, has changed the daily workup of breast cancer patients. At present, HER2 expression and/or amplification should be evaluated in every primary invasive breast cancer either at the time of diagnosis or at the time of recurrence, mostly to guide selection of trastuzumab in the adjuvant and/or metastatic setting. The adequate selection of patients is an essential step for indication of anti-HER2 therapy.

OBJECTIVE

This review focuses on the state of the art for HER2 evaluation in breast cancer, as well as expectations regarding future molecular assays based on mechanisms of resistance to HER2-driven therapy.

METHODS

Data were obtained by searching the PubMed database, including the terms 'HER2', 'in situ hybridisation', 'immunohistochemistry', 'trastuzumab', 'breast cancer', 'therapy', 'resistance' and 'tyrosine-kinase inhibitors', with a preference for updated publications.

CONCLUSION

Pathologists have a central role in the selection of patients who will benefit from anti-HER-based therapies, with a responsibility to obtain the most reliable results for immunohistochemistry and in situ hybridisation techniques. Pre-analytical variables, such as type of fixative and time of fixation, are critical to guarantee consistent and quality assays, as well as to facilitate interpretation and decrease interobserver variability. Rigorous quality control and centralisation of techniques/interpretation of results are recommended to guarantee consistent assays.