Response prediction to neoadjuvant chemotherapy: comparison between pre-therapeutic gene expression profiles and in vitro chemosensitivity assay.

Although the use of (neo-)adjuvant chemotherapy in breast cancer patients has resulted in improved outcome, not all patients benefit equally. We have evaluated the utility of an in vitro chemosensitivity assay in predicting response to neoadjuvant chemotherapy. Pre-therapeutic biopsies were obtained from 30 breast cancer patients assigned to neoadjuvant epirubicin 75 mg/m2 and docetaxel 75 mg/m2 (Epi/Doc) in a prospectively randomized clinical trial. Biopsies were subjected to a standardized ATP-based Epi/Doc chemosensitivity assay, and to gene expression profiling. Patients then received 3 cycles of chemotherapy, and response was evaluated by changes in tumor diameter and Ki67 expression. The efficacy of Epi/Doc in vitro was correlated with differential changes in tumor cell proliferation in response to Epi/Doc in vivo (p = 0.0011; r = 0.73670, Spearmans rho), but did not predict for changes in tumor size. While a pre-therapeutic gene expression signature identified tumors with a clinical response to Epi/Doc, no such signature could be found for tumors that responded to Epi/Doc in vitro, or tumors in which Epi/Doc exerted an antiproliferative effect in vivo. This is the first prospective clinical trial to demonstrate the utility of a standardized in vitro chemosensitivity assay in predicting the individual biological response to chemotherapy in breast cancer.

Tuberin and p27 expression in breast cancer patients with or without BRCA germline mutations.

BACKGROUND: Tuberin, the protein product of tuberous sclerosis gene 2 (TSC2), is the functional component of the TSC1/TSC2 complex and regulates cell cycle through activation of the cyclin-dependent kinase inhibitor p27. The transcriptional regulation of p27 is, however, also linked to a functional BRCA protein, since in BRCA1 mutant breast cancer cells, which lack the ability to repair DNA damages by homologous recombination, p27 is down-regulated. We have therefore investigated the expression of both tuberin and p27 in normal breast tissue, and in malignant epithelium from women with and without a BRCA mutation. MATERIALS AND METHODS: immunohistochemistry was used to compare p27 and tuberin protein expression in 26 BRCA1 and 2 mutation carriers, in 53 matched breast cancer patients without a family history, and in 74 benign breast tissues in a case-control study. RESULTS: Tuberin and p27 protein expression were significantly more common in benign when compared to malignant breast tissue (p = 0.01 and p = 0.03), but no difference was observed when sporadic and BRCA-mutated breast cancer specimen were compared. Tuberin and p27 were positively correlated with each other (p = 0.0017, r = 0.2527). Furthermore, p27 expression was positively correlated with ER and PR, and negatively correlated with tumor size. The expression of tuberin and p27 in breast cancer was not correlated with clinical outcome. CONCLUSION: Our results suggest that tuberin and p27 are aberrantly expressed in malignant tissue, but their expression does not appear to be dependent on the BRCA mutation state of a breast cancer patient.

Differential expression pattern of estrogen receptors, aromatase, and sulfotransferase in breast cancer tissue and corresponding lymph node metastases.

Patients with hormone receptor positive breast cancer who are treated with endocrine therapy generally have a good prognosis. However, resistance to hormonal therapy and progression occurs, and the reasons for this are manifold. It has been proposed that the local estrogenic environment has a role in the process of local invasion and progression. We have determined the expression pattern of estrogen receptor α, estrogen receptor ß, and the epithelial and stromal expression of the estrogen-metabolizing enzymes aromatase and sulfotransferase by immunohistochemistry in tissue arrays, containing 50 paraffin-embedded sets of tissues obtained from breast cancer and from corresponding metastatic axillary lymph nodes of the same patients. We have found statistically significant higher estrogen receptors α and ß expression in primary tumors than in corresponding lymph node metastases (p = 0.0004 and p = 0.003, respectively). Aromatase was also expressed more frequently in epithelial as well as in stromal cells of the malignant tumor when compared to according lymph node metastases (p = 0.08 and p = 0.12, respectively). While in lymph node metastases only estrogen receptor α and stromal aromatase expression were correlated (p = 0.01), significant associations were seen between the estrogen receptor ß and sromal aromatase, and epithelial sulfotransferase (p = 0.0006 and p = 0.03, respectively) in the primary tumor. We hypothesize that the decreased expression of local estrogens by aromatase, in combination with a decreased expression of estrogen receptors α and ß in lymphatic metastases, renders these metastases hormone insensitive and could contribute to the poor response to endocrine therapy that is often seen in nodal-positive tumors.

Beta-hCG/LH receptor (b-HCG/LH-R) expression is increased in invasive versus preinvasive breast cancer: implications for breast carcinogenesis?

INTRODUCTION: The role of the b-HCG/LH/LH-R system in breast cancer is conflicting. Whereas some reports suggest a protective effect of b-HCG on breast epithelium, vitro studies implicate a role of b-HCG/LH-R in the development and growth of breast tumors. MATERIAL AND METHODS: In order to further investigate a possible involvement of b-HCG/LH-R in breast carcinogenesis, immunofluorescence analyses of b-HCG/LH-R expression was performed on 70 preinvasive and adjacent invasive breast cancer specimen using tissue microarrays (TMAs). RESULTS: In 37 preinvasive samples available for further analysis, b-HCG/LH-R was found in 8/37 samples (21.6%; weak, intermediate and strong staining in 4/37 (10.8%), 2/37 (5.4%) and 2/37 (5.4%). In contrast, b-HCG/LH-R expression was observed in 19/27 (70.4%) adjacent invasive specimen with weak, moderate and strong immunostaining in 10/27 (37.0%), 6/27 (22.2%) and 3/27 (11.1%), respectively. This was statistically significant when compared to preinvasive components (P = 0.001, Chi Square Test). CONCLUSIONS: Based on the observation that b-HCG/LH-R was found to be selectively upregulated in invasive tumor components, we suggest that under certain circumstances, sensitivity of ductal cells to hormones that target b-HCG/LH-R could favour mammary carcinogenesis.

HER2 overexpression and activation, and tamoxifen efficacy in receptor-positive early breast cancer.

OBJECTIVES: Tamoxifen is a partial ER antagonist that is highly effective in the treatment of receptor positive breast cancer. It significantly reduces recurrence and improves survival in both pre- and postmenopausal women. Unfortunately, many ER+ positive tumors progress despite tamoxifen treatment and until now, no possibility exists to prospectively identify tamoxifen-resistant tumors. It has been suggested that that in HER2 over-expressing tumors, cross-talk via activated HER2 receptors is a key mechanisms by which tumors become tamoxifen-resistant. METHODS: We have therefore used immunohistochemistry to analyze the expression of HER2 and activated ptyr-1248 HER2 in 408 women of ER+, early breast cancer who had received at least 2 years of adjuvant tamoxifen. We then analyzed possible associations between HER2 and pHER2 expression, and prognostic parameters, and evaluated the effect of HER2 expression and survival. RESULTS: With HER2 being positive in 12 of 208 (2.9%) of ER+ positive tumors, HER2 overexpression was found to be considerably less common in ER+ tumors than what has been thought previously. The majority of HER2 overexpressing tumors, however, also expressed the activated receptor form (r = 0.664; P < 0.0001). Both HER2 and pHER2 are moderately correlated with Grading (r = 0.138; P = 0.0052 and r = 0.118; P = 0.0241, respectively) and nodal involvement (r = 0.163; P = 0.0018 and r = 0.134; P = 0.016, respectively), but neither HER2 nor its activated form are significant predictors of RFS, DFS, or OS. CONCLUSIONS: Taken together, we have demonstrated that in ER+ breast cancer, the HER2 receptor is commonly activated, but its low prevalence in ER+ tumors does not render it a useful prognostic parameter in tamoxifen-treated patients.

Incomplete surgical resection of ductal carcinomas in situ results in activation of ERBB2 in residual breast cancer cells.

ERBB2 amplification and consecutive overexpression is a predictor for poor prognosis in breast cancer patients. In addition, incomplete resection of ERBB2-overexpressing tumors leads to increased proliferation of residual breast cancer cells. While the local release of cytokines is thought to be responsible for the malignant behavior of remaining tumor tissue, the exact mechanism is still unknown. We have analyzed epidermal growth factor receptor (EGFR), activated (p)EGFR, and activated (p)ERBB2 protein expression in ERBB2-overexpressing and in non-ERBB2-overexpressing tumors from patients who underwent breast surgery and consecutive re-excision for involved margins, and compared expression levels by immunohistochemistry. While overall ERBB2 protein expression in the initial and the re-excised sample were comparable, we observed an increase in pERBB2 in ductal carcinomas in situ in both, ERBB2-overexpressing (16/21 vs 24/24; P=0.018, chi(2) test) and non-ERBB2-overexpressing tumors (3/28 vs 5/12; P=0.025, chi(2) test). pERBB2 was not increased in invasive tumors, regardless on whether the samples had been taken from a ERBB2-overexpressing (9/25 vs 6/17; P=0.261, chi(2) test) or a non-ERBB2-overexpressing tumor (1/27 vs 0/8; P=0.581, chi(2) test). EGFR expression was only detected in 1/47 ERBB2-overexpressing primary tumors and 2/48 non-ERBB2-overexpressing tumors, and was undetectable in re-excised specimen. Taken together, we have demonstrated an increase in ERBB2 receptor activation in incompletely resected preinvasive breast cancer. We hypothesize that receptor phosphorylation is caused by growth factor stimulation in response to intraoperative tissue damage, and perioperative inhibition of specific cytokines could become a promising therapeutic strategy.

The validity of complex breast cysts after surgery.

BACKGROUND: Breast cysts are the most common cause of benign breast masses. Simple breast cysts do not need further evaluation, but complex breast cysts require additional assessment due to the potential presence of malignancy. However, these complex cysts have rarely been examined and quantified according to the associated cancer detection rate. Our study is the first investigation to evaluate the malignancy rate of complex breast cysts identified by histopathological results. METHODS: Imaging findings of complex cysts were correlated retrospectively with clinical and pathologic outcomes. We detected a malignancy rate of 14%. Sonographic criteria of a complex cyst such as thick cyst wall (P = .0006), lobulation (P = .01), and hyperechogenicity (P = .04) were predictive of neoplasm. Two or more criteria combined were associated with a 13.6-fold higher risk of malignancy (P <.0001). CONCLUSION: Based on our results we reinforce the importance of adequate assessment of complex breast cysts to prevent a missed or delayed diagnosis of malignancy.

No evidence that GATA3 rs570613 SNP modifies breast cancer risk.

GATA-binding protein 3 (GATA3) is a transcription factor that is crucial to mammary gland morphogenesis and differentiation of progenitor cells, and has been suggested to have a tumor suppressor function. The rs570613 single nucleotide polymorphism (SNP) in intron 4 of GATA3 was previously found to be associated with a reduction in breast cancer risk in the Cancer Genetic Markers of Susceptibility project and in pooled analysis of two case-control studies from Norway and Poland (P (trend) = 0.004), with some evidence for a stronger association with estrogen receptor (ER) negative tumours [Garcia-Closas M et al. (2007) Cancer Epidemiol Biomarkers Prev 16:2269-2275]. We genotyped GATA3 rs570613 in 6,388 cases and 4,995 controls from the Breast Cancer Association Consortium (BCAC) and 5,617 BRCA1 and BRCA2 carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). We found no association between this SNP and breast cancer risk in BCAC cases overall (OR(per-allele) = 1.00, 95% CI 0.94-1.05), in ER negative BCAC cases (OR(per-allele) = 1.02, 95% CI 0.91-1.13), in BRCA1 mutation carriers RR(per-allele) = 0.99, 95% CI 0.90-1.09) or BRCA2 mutation carriers (RR(per-allele) = 0.93, 95% CI 0.80-1.07). We conclude that there is no evidence that either GATA3 rs570613, or any variant in strong linkage disequilibrium with it, is associated with breast cancer risk in women.

Differential gene expression profile in breast cancer-derived stromal fibroblasts.

BACKGROUND: Breast cancer is characterized by malignant transformation of epithelial cells, but stromal cells also play an important role in tumorigenesis. While tumor-derived fibroblasts display unique phenotypic properties, it is unclear whether they also represent are a specific subpopulation. MATERIALS AND METHODS: Stromal fibroblasts deriving from malignant tissue of 10 women with invasive breast cancer, and from normal breast tissue of 10 women with benign breast disorders, were subjected to differential complementary DNA Microarray Analysis by using a 2,400 gene cDNA array. Individual gene expression pattern were confirmed by RT-PCR. RESULTS: In a cDNA array that allows to analyze the differential gene expression of more than 2,400 genes, the mRNA expression of 135 genes were increased more than 2 fold in fibroblasts from malignant breast tumors. The majority of these genes encode tumor-promoting cytokines, transcription factors and cell-matrix associated proteins. The mRNA expression of 110 genes decreased to less than 0.5 fold. The remaining 2,155 genes were not significantly altered. RT-PCR performed on individual biopsies from breast cancer and normal breast tissues confirmed the validity of the pooled gene expression signature. CONCLUSION: Breast cancer-derived stromal fibroblasts show a distinctive gene expression pattern that differentiates them from normal breast stroma. Our observation of increased expression of tumor promotion-associated genes even in the absence of adjacent malignant epithelium suggests that tumor stroma is comprised of a fibroblastic subpopulation that provides for a microenvironment which supports tumor growth and invasion.

Differential spatial expression and activation pattern of EGFR and HER2 in human breast cancer.

Overexpression of HER family members is a well established prognostic factor and identifies potential targets for antibody-based receptor blocking strategies. While several studies have analyzed the expression of HER2 and other HER-family members in malignant tumors, considerably less is known about their expression and activation in non-involved breast tissue from breast cancer patients. We have therefore investigated the differential expression of EGFR, HER2, and their tyrosine-kinase activated forms (ptyr-1248 Her-2 and ptyr-845 EGFR) in 63 tumor specimen containing: a) malignant epithelium, b) in non-malignant tissue located at the peritumoral margin, and c) in uninvolved breast tissue obtained from tissue distant from the tumor. Using immunohistochemistry (IHC), we found significantly higher HER2 protein expression levels in malignant epithelium than in marginal and peripheral non-malignant epithelium (p=1.3 x 10(-10) Fisher's exact test). Epithelial EGFR expression did not differ between the three tissue types, but stromal EGFR protein was significantly more common in marginal and peripheral tissues when compared to tumor tissues (p=0.008, Fisher's exact test). When analyzing activated receptor forms, we found epithelial ptyr-1248 HER2 expression in one tumoral, one marginal and one peripheral sample. We did not observe ptyr-845 EGFR in any of the samples analyzed. We found a significant overall correlation between epithelial and stromal EGFR expression (r=0.442; p<0.0001; Spearman's Rho), and between stromal EGFR expression and normal tissue type (r=0.170; p<0.02; Spearman's Rho). Epithelial HER2 expression and normal tissue type (r=0.492; p<0.0001; Spearman's Rho) were inversely correlated. Taken together, we have observed a differential expression pattern of EGFR, HER2, and activated HER2 that is dependent on the spatial relation to a malignant tumor. Our findings of decreased intratumoral EGFR expression and the absence of activated EGFR suggests that, in contrast to HER2, EGFR inhibition might not be an ideal target for antibody therapy.

Gene profiling in Pap-cell smears of high-risk human papillomavirus-positive squamous cervical carcinoma.

OBJECTIVE: The purpose of the study was to investigate benign and malignant squamous cervical cells obtained by cervical swabs with regard to differentially expressed genes and gene expression profiling, in order to evaluate the biological behavior and clinical outcome of cervical malignancies. METHODS: Cervical squamous cells from six women with high-risk human papillomavirus positive [HR-HPV(+)] cervical carcinoma and from six HPV-negative women with normal ectocervical cells were analyzed by cDNA array. RESULTS: cDNA over-expression of several genes such as MET (c-met), Nm23-H1 (NME1), EGFR, KGFR, Nm23-H2 (NME2), ERBB2 (c-erbB-2), cyclin-dependent kinase inhibitor 4 (CDKN2A, p16INK4A), cytokeratin 8 (KRT8), KRAS (K-ras), FLT1, KGF (FGF7), BCL2-like 2 protein (BCL2L2), ERBB4, MYCN (N-myc), cyclin D1 (CCND1), KIT (c-kit), secreted phosphoprotein 1 (SPP1) and STAT1, was significant in cervical squamous cell carcinoma (CSCC). Gene expression was downregulated for 13 genes in CSCC, such as interleukin 1 alpha (IL1A), the transforming growth factor receptor beta superfamily (TGFbeta; TGFB), some members of the insulin-like growth factor binding proteins (IGFBPs) and the integrin family (ITGA6, ITGB1). CONCLUSION: This study was focused on the gene expression profiling of HR-HPV(-) and (+) cervical squamous cells and CSCC obtained by cytobrush. We observed gene expression patterns and signaling pathways that permit the investigator to distinguish between benign squamous cervical cells and CSCC with and without HPV infection.

Selective spatial upregulation of intratumoral stromal aromatase in breast cancer patients: evidence for imbalance of local estrogen metabolism.

The suppression of local estrogens levels is of key importance in the treatment of ER-positive breast cancer. Essentially all endocrine strategies act by either suppressing estrogen formation or competitively inhibiting receptor-binding in tumor cells. Nevertheless, little is still known about the local expression of aromatase and sulfotransferase which are the key modulators of intra-tumoral estrogen levels. We have performed immunohistochemostry to investigate the expression of aromatase and sulfotransferase in 42 samples obtained directly from malignant breast tumors, and compared it to biopsies obtained from uninvolved tissue in the vicinity of the invasion front, and to distant breast tissue. We found that aromatase was equally detectable in both tumor epithelial and stroma, but was mostly epithelial in non-malignant tissues (P=0.00008, Fisher's exact test). Also, aromatase protein expression was significantly more common in tumoral stroma when compared with peritumoral and distant breast stroma (P=0.00005, and P<0.00001 respectively). With the notable exception of cystosarcoma phylloides, sulfotransferase protein was detectable only in epithelial tissues, regardless of the location within the diseased breast. However, epithelial sulfotransferase was correlated with epithelial aromatase (r=0.35461, P=0.0009, Spearman's rho test) and with the epithelial ER status (r=0.29313, P=0.005). We have demonstrated a differential aromatase and sulfotransferase protein expression pattern that is dependent on the spatial relation to a malignant breast tumor. Our results indicate a net increase in intratumoral active estrogen levels through increased stromal aromatization, while physiological local inactivation by sulfotransferase activity remains essentially unchanged.