Dihydrotestosterone upregulates the expression of epidermal growth factor receptor and ERBB2 in androgen receptor-positive bladder cancer cells

Androgen receptor (AR) signals play important roles in bladder carcinogenesis and tumor progression. Activation of the epidermal growth factor receptor (EGFR) family, including EGFR and ERBB2, leads to bladder cancer cell growth and correlates with poor patients' prognosis. However, cross talk between AR and EGFR/ERBB2 pathways in bladder cancer remains poorly understood. In AR-positive bladder cancer UMUC3 and TCC-SUP cells, dihydrotestosterone (DHT) increased the expression of EGFR and ERBB2 both in mRNA and in protein levels, and an anti-androgen hydroxyflutamide antagonized the effect of DHT. The necessity of AR was confirmed by silencing the receptor, using short hairpin RNA (shRNA), in UMUC3 cells, as well as by expressing the receptor in AR-negative 5637 cells. Of note were much higher basal levels of EGFR and ERBB2 in UMUC3-control-shRNA than in UMUC3-AR-shRNA and those of EGFR in 5637-AR than in 5637-V. DHT additionally upregulated the levels of phosphorylation of EGFR (pEGFR) and its downstream proteins AKT (pAKT) and ERK1/2 (pERK), induced by EGF treatment, in AR-positive cells. Immunohistochemistry on cystectomy specimens showed strong associations between expressions of AR and EGFR (P=0.0136), pEGFR (P=0.0041), ERBB2 (P=0.0331), or pERK (P=0.0274), but not of pAKT (P=0.5555). The Kaplan-Meier and log-rank tests further revealed that positivity of AR (P=0.0005), EGFR (P=0.2425), pEGFR (P=0.1579), ERBB2 (P=0.2997), or pERK (P=0.1270) and negativity of pAKT (P=0.0483) were associated with tumor progression. Our results indicate that AR activation upregulates the expression of EGFR and ERBB2 in bladder cancer cells. AR signals may thus contribute to the progression of bladder cancer via regulation of the EGFR/ERBB2 pathways.     

Met induces diverse mammary carcinomas in mice and is associated with human basal breast cancer

Understanding the signaling pathways that drive aggressive breast cancers is critical to the development of effective therapeutics. The oncogene MET is associated with decreased survival in breast cancer, yet the role that MET plays in the various breast cancer subtypes is unclear. We describe a knockin mouse with mutationally activated Met (Met^mut) that develops a high incidence of diverse mammary tumors with basal characteristics, including metaplasia, absence of progesterone receptor and ERBB2 expression, and expression of cytokeratin 5. With gene expression and tissue microarray analysis, we show that high MET expression in human breast cancers significantly correlated with estrogen receptor negative/ERBB2 negative tumors and with basal breast cancers. Few treatment options exist for breast cancers of the basal or trastuzumab-resistant ERBB2 subtypes. We conclude from these studies that MET may play a critical role in the development of the most aggressive breast cancers and may be a rational therapeutic target.     

Prognosis in hormon receptor negative breast cancer patients according to ERBB2 status

Breast carcinomas represent a heterogenous group of tumors and recent studies have demonstrated several subtypes of breast cancer by gene expression profiles. This study aimed to compare hormon receptor negative (ER-/PR-/ERBB2+) and triple negative (ER-/PR-/ERBB2-) patients in terms of prognosis and to show that molecularly defined subtypes can be distinguished by conventional laboratory methods. Patients treated between 2001-2007 for hormon receptor negative breast cancer were retrospectively studied. In addition to the conventional prognostic factors, effect of ERBB2 status of the patients on disease-free and overall survival was evaluated. Hormon receptor and ERBB2 status were determined by immunuhistochemistry and fluorescence in-situ hybridization. 141 patients were eligible for the study. Number of patients with ERBB2 positive and triple negative tumors was 70 and 71, respectively, and two groups were comparable in terms of study parameters. Tumor size, grade, axillary status, patient groups, and adjuvant chemotherapy and radiotherapy showed significant impact on disease-free survival and overall survival was significantly dependent on axillary status, type of surgery, and patient groups in univariate analysis. In multivariate analysis, patient groups, tumor grade, and axillary status were independent prognostic factors for disease-free survival whereas patient groups, extent of surgery, and axillary status were independent prognostic factors for overall survival. This study has indicated that ERBB2 negative patients had worse survival among hormon receptor negative breast cancer patients and showed that molecularly defined subtypes of breast cancer can be differentiated by immunuhistochemistry in terms of prognosis.     

Alterations in phenotypic biochemical markers in bladder epithelium during tumorigenesis.

Phenotypic biochemical markers of oncogenesis and differentiation were mapped in bladder biopsies to investigate changes that occur in bladder tumorigenesis and to identify markers for increased bladder cancer risk. Touch preparations from biopsy specimens from 30 patients were obtained from tumors, the adjacent bladder epithelium, and random distant bladder epithelium. Markers, including DNA ploidy, epidermal growth factor receptor (EGFR), and oncoproteins, were quantified in individual cells by using quantitative fluorescence image analysis. Cluster analysis revealed the markers fell into three independent groups: (i) G-actin and EGFR; (ii) ploidy, cytology, and p185 (HER-2/neu oncoprotein) (ERBB2); and (iii) p300, a low-grade tumor antigen. Each marker displayed a gradient of abnormality from distant field to adjacent field to tumor. Different patterns for each marker suggested a developmental sequence of bladder cancer oncogenesis; G-actin was altered in 58% of distant biopsies (vs. 0/6 normals, P < 0.001), ploidy and cytology were altered in < 20% of distant fields and approximately 80% of tumors, and the other markers were intermediate. Patterns of EGFR and p185 suggest low-and high-grade tracks diverge early (P < 0.05 by Mann-Whitney U test for EGFR and ANOVA for p185). In conclusion, this study shows that a sequence of phenotypic changes accompanies development and progression of bladder cancers. Biochemical alterations in cells of the bladder field are often detectable before abnormal pathology, and markers previously thought to be limited to tumors were found in the field. The hierarchy of expression may be useful in identifying high-risk patients, assessing completeness of response to therapy, and monitoring and predicting recurrence.     

Inverse regulation of human ERBB2 and epidermal growth factor receptors by tumor necrosis factor alpha.

Recombinant human tumor necrosis factor (TNF) alpha decreased the expression of ERBB2 mRNA by stimulating p55 TNF receptors of pancreatic tumor cells. This decrease contrasts with an increase in epidermal growth factor receptor (EGFR) mRNA. Both effects were selectively achieved by TNF-alpha or -beta, whereas interferon alpha or gamma or transforming growth factor beta showed no such effects. The inverse regulatory effects of TNF on ERBB2 and EGFR mRNA levels were evoked by different signaling pathways of p55 TNF receptors. The TNF-mediated ERBB2 mRNA decrease was followed by a reduction in protein. Four of five pancreatic tumor cell lines exhibited this down-regulation. This decrease of ERBB2 is a singular example of a modulation of this growth factor receptor by TNF. Overexpression of ERBB2 has been reported to cause resistance to TNF and other cytotoxic cytokines. In our study we show that the TNF-mediated down-regulation of ERBB2 in pancreatic tumor cells is accompanied by an increase in growth inhibition at low doses of TNF. The simultaneous alteration of the ERBB2/EGFR balance by TNF represents a striking model of cytokine receptor transregulation in the growth control of malignant pancreatic epithelial cells.     

Intratumoral IGF-I protein expression is selectively upregulated in breast cancer patients with BRCA1/2 mutations

BRCA1/2 mutations predispose to early onset breast and ovarian cancers. The phenotypic expression of mutant alleles, however, is thought to be modified by factors that are also involved in the pathogenesis of sporadic breast cancer. One such protein is IGF-I, one of the strongest mitogens to breast cancer cells in vitro. We have utilized immunohistochemistry to compare the intratumoral IGF-I and IGF-I receptor (IGF-IR) protein expression in 57 BRCA1/2 mutation carriers and 102 matched breast cancer patients without a family history in a nested case-control study. BRCA1 silencing by siRNA was used to investigate the effect of BRCA mutations on IGF-I protein expression. IGF-I protein expression was detected in tumoral epithelium and surrounding stroma, and was significantly upregulated in tumors of BRCA mutation carriers when compared with matched sporadic tumors (epithelial: 87.7% vs 61.8%, P=0.001; stromal: 73.7% vs 34.3%, P<0.001). By contrast, IGF-IR protein expression was confined to malignant epithelium and was unchanged in mutation carriers (52.6% vs 39.2%, P=0.310). While in mutation carriers IGF-IR protein expression was significantly correlated with both epithelial (P=0.003) and stromal IGF-I (P=0.02), this association was less pronounced in sporadic breast cancer (P=0.02 respectively). siRNA-mediated downregulation of BRCA1 in primary human mammary gland cells triggered upregulation of endogenous intracellular IGF-I in vitro. The increased intratumoral IGF-I protein expression in BRCA mutation carriers suggests an involvement of the IGF-I/IGF-IR axis in the biological behavior of breast cancers in this population and could define a potential therapeutic target.     

Repeated observation of breast tumor subtypes in independent gene expression data sets

Characteristic patterns of gene expression measured by DNA microarrays have been used to classify tumors into clinically relevant subgroups. In this study, we have refined the previously defined subtypes of breast tumors that could be distinguished by their distinct patterns of gene expression. A total of 115 malignant breast tumors were analyzed by hierarchical clustering based on patterns of expression of 534 "intrinsic" genes and shown to subdivide into one basal-like, one ERBB2-overexpressing, two luminal-like, and one normal breast tissue-like subgroup. The genes used for classification were selected based on their similar expression levels between pairs of consecutive samples taken from the same tumor separated by 15 weeks of neoadjuvant treatment. Similar cluster analyses of two published, independent data sets representing different patient cohorts from different laboratories, uncovered some of the same breast cancer subtypes. In the one data set that included information on time to development of distant metastasis, subtypes were associated with significant differences in this clinical feature. By including a group of tumors from BRCA1 carriers in the analysis, we found that this genotype predisposes to the basal tumor subtype. Our results strongly support the idea that many of these breast tumor subtypes represent biologically distinct disease entities.     

Activation of multiple cancer-associated genes at the ERBB2 amplicon in breast cancer

During the past decade the role of the ERBB2 (neu/HER2) oncogene as an important predictor of patient outcome and response to various therapies in breast cancer has been clearly established. This association of ERBB2 aberrations with more aggressive disease and poor clinical outcome, together with the high prevalence of such alterations in breast cancer, has also made ERBB2 an attractive target for therapy. A specific antibody-based therapy, Herceptin, directed against the extracellular domain of the ERBB2 receptor tyrosine kinase, was recently developed and several clinical trials have shown the therapeutic efficacy of this drug against ERBB2-positive breast cancer. However, a relatively large fraction of patients does not benefit from Herceptin treatment, indicating that other factors beyond ERBB2 itself must influence therapy response in ERBB2-positive tumors. It is well known that amplification of the 17q12-q21 region is the most common mechanism for ERBB2 activation in breast cancer and that it leads to simultaneous activation of several other genes. These co-amplified and co-activated genes may have an impact on disease progression and the clinical behavior of ERBB2-positive tumors and thus represent important targets of research. In this paper we discuss the current knowledge on the structure of the ERBB2 amplicon, the genes involved, and their possible contribution to breast cancer pathogenesis.     

The ubiquitin-binding protein p62 is expressed in breast cancers showing features of aggressive disease

p62 is a multi-functional protein, which induces nuclear factor-kappaB (NFkappaB) activation through multiple upstream signalling pathways, including those triggered by the epidermal growth factor (EGF) family of receptors. We hypothesised that p62 overexpression increased EGF family receptor expression and worse outcome in breast cancer would be associated. We stained a tissue microarray representing 523 breast cancers using a commercial guinea pig anti-human p62 sera and standard immunohistochemical methods to address this. Out of n = 106 tumours, 20.3% stained positively. p62 expression correlated with grade (P = 0.010) and distant metastasis (P = 0.04) and EGF receptor (EGFR) (P = 0.012), HER2 (P = 0.016), HER3 (P = 0.007) and HER4 (0.002) expressions. Though expression correlated with reduced 5-year survival (58.5 vs 73.6%), there was no association with overall disease specific survival. p62 expression may represent a marker of activation of the NFkappaB pathway.     

不同胃黏膜病变的细胞增殖变化规律及其意义

目的 研究胃黏膜不同病变时细胞增殖的变化规律及其意义,寻找有效的生物学指标来预测和早期诊断胃癌。方法 采用免疫组织化学SP法检测了30例慢性浅表性胃炎(CSG)、26例慢性萎缩性胃炎(CAG)、40例肠上皮化生(IM)、22例异型增生(DYS)、22例早期胃癌(EGC)和26例进展期胃癌(AGC)的增殖细胞核抗原(PCNA)、表皮生长因子受体(EGFR)、转化生长因子β受体(TGFβR)Ⅰ和TGFβR Ⅱ的表达。所得数据采用秩和检验及Spearman等级相关分析。结果 相应于CSG、CAG、IM、DYS、EGC和AGC不同的胃黏膜病变,PCNA和EGFR的表达递增(P<0.0001),TGFβR Ⅰ(P=0.007)和TGFβR Ⅱ(P<0.0001)的表达递减。PCNA标记指数在DYS时高于CSG、CAG和IM,低于EGC和AGC,其差异有显著性(P<0.0001);EGFR在IM和DYS时比CSG和CAG明显升高,差异有显著性(P<0.0001);TGFβR Ⅰ在EGC和AGC时明显下降,与CSG相比差异有显著性(P=0.007);TGFβRⅡ在AGC时明显下降,与CSG、CAG、IM、DYS及EGC相比差异有显著性(P<0.13001)。EGFR表达与PCNA的表达呈正相关,TGFβR Ⅰ和TGFβR Ⅱ与PCNA分别呈负相关,TGFβR Ⅰ和TGFβRⅡ呈正相关。结论 不同的胃黏膜病变中,DYS是细胞增殖水平发生变化的关键环节;EGFR的升高和TGFβR的下降可能通过对细胞增生水平的调节促进胃癌的发生。     

Specific expression of the pS2 gene in subclasses of breast cancers in comparison with expression of the estrogen and progesterone receptors and the oncogene ERBB2

The expression of the pS2 gene, which is induced by estrogen in the breast cancer cell line MCF-7, has been investigated in breast cancers by using pS2 mRNA determination in tumor specimens and immunocytochemistry to identify pS2 protein in paraffin-embedded sections. Using these assays we show that determination of pS2 gene expression allows the definition of subclasses of estrogen-receptor-containing breast cancers that may be used to more precisely identify estrogen-dependent tumors. Tumor specimens have also been analyzed for the presence of mRNAs for the estrogen receptor and for the ERBB2 oncogene. No evidence for the presence of truncated forms of estrogen-receptor mRNA has been found, and overexpression of the ERBB2 oncogene did not correlate with the steroid receptor status or pS2 gene expression.     

Growth,invasion, metastasis,differentiation, angiogenesis and apoptosis of gastric cancer regulated by expression of PTEN encoding products

AIM: To investigate expression of PTEN in gastric cancer and to explore its roles in tumorigenesis and progression of gastric cancer.METHODS: Formalin-fixed and paraffin-embedded tissues of adjacent non-tumor mucosa and primary foci from 113cases of gastric cancers were studied for the expression of PTEN and Caspase-3 andmicrovessel density (MVD)by streptavidin-peroxidase (S-P) immunohistochemistry with antibodies against PTEN, Caspase-3, and CD34. The relationship between PTEN and Caspase 3 expression and clinicopathological parameters of tumors was compared.RESULTS: Primary gastric cancer cells expressed PTEN less frequently than adjacent epithelial cells of primary foci (54.9％ vs89.4％; P=0.000, χ2=33.474). PTEN expression was significantly associated with invasive depth (P=0.003,rs=0.274), metastasis (P=0.036, rs=0.197), growth pattern (P=0.008, rs=0.282), Lauren′s classification (P=0.000,rs=0.345), and histological classification (P=0.005, rs=0.262)of tumors, but not with tumor size (P=0.639, rs=0.045),Borrmann′s classification (P=0.544, rs=0.070) or TNM staging (P=0.172, rs=0.129). PTEN expression was negatively correlated with MDV in primary gastric cancer (P=0.020,F=5.558). Primary gastric cancer cells showed less frequent immunoreactivity to Caspase-3 than adjacent epithelial cells of primary foci (32.7 ％ vs 50.4 ％; P=0.007,χ2=7.286).Caspase-3 expression was dependent of PTEN expression in primary gastric cancer cells (P=0.000, χ2=15.266).CONCLUSION: Down-regulated expression of PTEN plays an important role in tumorigenesis, progression, growth,differentiation and angiogenesis of gastric cancer. Low expression of PTEN can decrease expression of Caspase-3to disorder apoptosis of tumor cells, which might explain the molecular mechanisms of PTEN contributions to tumorigenesis and progression of gastric cancer.     

ERBB2 amplification in breast cancer analyzed by fluorescence in situ hybridization.

We illustrate the use of fluorescence in situ hybridization (FISH) for analysis of ERBB2 oncogene copy number, the level of amplification (here defined as the ratio of ERBB2 copy number to copy number of chromosome 17 centromeres), and the distribution of amplified genes in breast cancer cell lines and uncultured primary breast carcinomas. The relative ERBB2 copy number determined by FISH in 10 breast cancer cell lines correlated strongly with Southern blot results (r = 0.98) when probes for an identical reference locus were used in the two methods. Metaphase analysis of cell lines showed that amplified ERBB2 copies always occurred in intrachromosomal clusters but that the number and chromosomal location of these clusters varied among the cell lines. In interphase nuclei of primary tumors showing ERBB2 amplification (10/44), ERBB2 copies were seen as one to four clusters, also suggesting intrachromosomal localization. Regardless of the average level of amplification, all these tumors contained highly amplified cell subpopulations with at least 25, and sometimes more than 100, ERBB2 copies per cell. Tumors that did not show amplification by FISH (34/44) had an average of one to five ERBB2 copies scattered randomly in the nuclei and completely lacked cells with high copy levels. FISH results on primary tumors were concordant with slot blot results on amplification and with immunohistochemical detection of overexpression. Quantitative analysis of ERBB2 amplification by FISH may improve prognostic assessments based on the pattern of amplification and detection of heavily amplified tumor cell subpopulations.     

EGFR LI and Ki-67 LI are independent prognostic parameters influencing survivals of surgically treated squamous cell lung cancer patients

In literature there are still opinion differences concerning the prognostic significance of epidermal growth factor receptor (EGFR) expression and proliferative potential in patients with non small cell lung cancer (NSCLC). This prompted us to study those parameters. The Ki-67 labeling index (Ki-67 LI), EGFR labeling index (EGFR LI), and mitotic index (MI) were analyzed in the group of 78 consecutive, surgically treated squamous cell lung cancer (SqCLC) patients. The expression of Ki-67 and EGFR protein was visualized on formalin fixed, paraffin embedded sections using immunohistochemistry (IHC). Mitotic index was assessed on formalin fixed, paraffin embedded sections, stained with hematoxylin and eosin using morphological criteria. Mean values of Ki-67 LI and MI were higher for G2+G3 tumors than for G1 tumors. EGFR LI was higher for G1+G2 than for G3 tumors, and for pT3 than for pT1+pT2 tumors. Patients having tumors with Ki-67 < or =28% or (EGFR LI < or =13% or EGFR LI >80%) survived significantly shorter than those having tumors with Ki-67 LI >28% or 13%< EGFR LI < or =80%. In multivariate analysis, 13%> or = EGFR LI <80% and Ki-67 LI < or =28% were independent negative prognostic parameters influencing survivals of SqCLC patients.     

ErbB2 is required for ductal morphogenesis of the mammary gland

The ERBB2/HER2/NEU receptor tyrosine kinase gene is amplified in up to 30% of human breast cancers. The frequent and specific selection of this receptor kinase gene for amplification in breast cancer implies that it has important normal functions in the mammary gland. To investigate the functions of ErbB2 during normal mouse mammary gland development, we transplanted mammary buds from genetically rescued ErbB2(-/-) embryos that express ErbB2 in the cardiac muscle. ErbB2(-/-) mammary buds transplanted to a wild-type mammary fat pad support outgrowth of an epithelial tree that advances only slowly through the mammary fat pad at puberty. This penetration defect is associated with structural defects in terminal end buds, characterized by a decrease in body cell number, an increased presence of cap-like cells in the prelumenal compartment, and the presence of large luminal spaces. Lobuloalveolar development was not affected in glands that developed from ErbB2(-/-) transplanted tissue. The results may have implications for the aggressive phenotypes associated with ERBB2-overexpressing mammary carcinomas.     

Direct and immune mediated antibody targeting of ERBB receptors in a colorectal cancer cell-line panel

A significant proportion of colorectal cancer (CRC) patients are resistant to anti-ERBB1 [avian erythroblastic leukemia viral (v-erb-b) oncogene homolog, receptor for EGF] monoclonal antibodies (Mabs). We evaluated both immune and nonimmune effects of cetuximab (anti-ERBB1 Mab), trastuzumab (anti-ERBB2 Mab), pertuzumab (anti-ERBB2 Mab), and lapatinib (dual ERBB1 and ERBB2 tyrosine kinase inhibitor) in a large well-characterized panel of 64 CRC cell lines to find response predictive tumor characteristics. There was a significant correlation between the direct effects of cetuximab and lapatinib. Both agents were associated (P = 0.0004) with “triple’ wild-type status in KRAS, BRAF, and PIK3CA exon 20. Most cell lines were resistant to the direct effects of anti-ERBB2 Mabs, suggesting that the effects of lapatinib might mainly be through ERBB1. Microarray mRNA expression profiles of sensitive and resistant cell lines showed that although ERBB1 receptor or ligand levels did not associate with cetuximab sensitivity, high levels of ERBB2 (P = 0.036) and amphiregulin (P = 0.026) predicted sensitivity to lapatinib. However, higher ERBB1 expression predicted susceptibility to cetuximab-induced antibody-dependent cellular cytotoxicity and occurred independently of KRAS/BRAF/PIK3CA mutations (P = 0.69). Lapatinib may be an effective alternative therapy to cetuximab in triple wild-type tumors. Microarray analysis provides suggestive biomarkers for resistance. ERBB1 levels, independent of mutation status, predict immune killing. Therefore, anti-ERBB1 antibodies may be considered in CRC tumors with higher ERBB1 expression and favorable FcγR polymorphisms.     

Serum IL-6 and IL-12 levels in breast cancer patients

Previous studies indicated that interleukins 6 & 12 are multifunctional cytokines which regulate of immune response and cancer cell proliferation. We measured serum levels of these cytokines in 40 females with breast cancer and examined their correlation with clinicopathological variables including stages of the disease and estrogen and progesterone receptor expression on tumor cells. Serum levels of IL-6 (mean =111.38 pg/ml) as well as IL-12 (mean=1142.75 pg/ml) were significantly increased in breast cancer patients as compared to controls (mean 1.75 pg/ml &19.90 pg/ml respectively). A statistically significant correlation was found between levels of IL-6 as well as IL-12 and progression of the tumor (P < 0.05). However, no statistical difference was found in serum levels of these cytokines between metastatic and non-metastatic cases. Both cytokines negatively correlated with estrogen and progesterone receptor expression on tumor cells. In conclusion, serum levels of IL-6 and IL-12 are highly elevated in breast cancer patients and correlate with tumor progression. Assays for serum levels of IL-6 and IL-12 can be used as predictive non-invasive tests for tumor progression in breast cancer patients.     

Measurement of somatostatin receptor subtype 2 mRNA in breast cancer and corresponding normal tissue

Somatostatin analogs are effective in inhibiting growth of human breast cancer cell lines. These antiproliferative effects are mediated by specific receptors located on cell membranes. The somatostatin receptor subtype 2 (sst2) is the principal mediator of somatostatin effects in normal and cancer cells, and its presence has already been demonstrated in breast cancer. The purpose of our study was to evaluate the clinical relevance of the expression of sst2 by quantifying its mRNA in a large group of infiltrating breast cancers and their corresponding normal tissues. The expression of sst2 mRNA was measured with quantitative real time RT-PCR in 169 breast cancers and in their corresponding unaffected tissues. We evaluated the association of sst2 expression with the commonest clinical-pathologic features of breast cancer. The correlation with a marker of cell proliferation (Ki-67) and with receptor concentration was also evaluated. In cancer tissues, we found that the absolute concentrations of sst2 mRNA were significantly higher in estrogen receptor (ER)-positive samples (P=0.002) as well as in lymph-node-negative cancers (P=0.04) (Student's t-test or one-way ANOVA). In addition, sst2 mRNA was significantly higher in breast cancers than in corresponding unaffected tissues (P=0.0002). However, when the clinical-pathologic parameters were considered, this gradient maintained its statistical significance only in tumors expressing positive prognostic markers, such as the presence of ER (P=0.0005) and progesterone receptors (PgR) (P=0005), and the lack of lymph-node involvement (P=0.0003). The same difference was also significant in postmenopausal women (P=0.001) and in T1 patients (P=0.001). In addition, sst2 mRNA expression was significantly higher (P=0.008) in low-proliferating breast cancers. Finally, we found that the quantitative expression of sst2 mRNA was directly related to the PgR concentration in breast cancer tissues (P<0.001). Our data seem to indicate that an upregulation of sst2 gene expression is a common feature of breast cancers which, on the basis of conventional predictive parameters, are expected to have a better prognosis. Featuring a possible role of somatostatin analogs in combined endocrine therapies for breast cancer, our results seem to confirm that the sst2 status of the tumor should be previously investigated.     

非小细胞肺癌表皮生长因子受体突变的检测与分子靶向治疗

目的探讨非小细胞肺癌患者表皮生长因子受体(EGFR)基因突变率和突变类型,分析其临床特征,并观察EGFR突变与表皮生长因子受体酪氨酸激酶抑制剂(EGFR-TKIs)治疗疗效的相关性。方法收集203例非小细胞肺癌患者外科手术、淋巴结活检、经皮肺穿刺活检、气管镜活检和胸腔积液沉渣石蜡标本,应用ADx-ARMS法进行EGFR基因突变检测,分析基因的突变率及其与临床特征的关系;观察非小细胞肺癌(NSCLC)接受EGFR-TKIs治疗的非小细胞肺癌患者的疗效。应用SPSS23.0软件进行统计学分析,计数资料比较采用χ2检验,采用Kaplan-Meier法计算患者的PFS,采用Log-Rank检验分析各种因素对生存期的影响。结果 203例NSCLC患者,男性116例,女性87例,年龄为25~82岁。吸烟指数≥400支/者61例,小于400支/年和不吸烟者142例,腺癌152例,鳞癌21例,腺鳞癌14例,其他NSCLC16例。203例NSCLC患者EGFR总突变率为51.2%(104/203),包括19外显子缺失突变51例(49.0%),21外显子L858R突变44例(42.3%),19del及L858R总突变率占所有突变的96.1%,18外显子G719X点突变3例(2.9%),19del+L858R双突变3例(2.9%),1例20ins,2例T790M突变分别为1例19del+T790M和1例L858R+T790M。EGFR基因阳性突变率女性组高于男性组(66.7%vs.36.2%);非吸烟组高于吸烟组(63.4%vs.16.4%);腺癌组高于鳞癌组(53.3%vs.33.3%),P0.05。而EGFR基因突变状况与标本类型如手术、淋巴结活检、肺穿刺活检、气管镜活检和胸腔积液沉渣标本间无统计学差异,P=0.418。101例接受TKI治疗的NSCLC患者客观缓解率(ORR)为61.4%,疾病控制率(DCR)为71.3%,中位疾病无进展生存期(PFS)为10个月。其中EGFR突变阳性患者接受EGFR-TKIs治疗的ORR及DCR均要显著高于EGFR突变阴性及EGFR突变状态未明确人群(88.6%vs.16.7%vs.43.1%,P=0.000;95.5%vs.16.7%vs.56.9%,P=0.000)。EGFR突变阳性患者接受EGFR-TKIs治疗的中位PFS较EGFR突变阴性及EGFR突变状态未明确患者延长,有统计学差异(P=0.001)。进一步分析EGFR突变阳性19del组NSCLC患者ORR、DCR均高于L858R组(91.2%vs.85%,P=0.646;100%vs.90%,P=0.201);19del组NSCLC患者TKI治疗后中位PFS 14.5个月较L858R组10个月长,有统计学差异(P=0.010)。结论非小细胞肺癌患者EGFR突变高,以女性、不吸烟、腺癌为优势人群,EGFR敏感突变阳性者对EGFR-TKI疗效好,EGFR突变中19del者较L858R疗效更佳,基因检测结果可以较好地预测分子靶向药物的疗效,降低肿瘤进展的风险。     

Examination of HER3 targeting in cancer using monoclonal antibodies

The human EGF receptor (HER/EGFR) family of receptor tyrosine kinases serves as a key target for cancer therapy. Specifically, EGFR and HER2 have been repeatedly targeted because of their genetic aberrations in tumors. The therapeutic potential of targeting HER3 has long been underestimated, due to relatively low expression in tumors and impaired kinase activity. Nevertheless, in addition to serving as a dimerization partner of EGFR and HER2, HER3 acts as a key player in tumor cells’ ability to acquire resistance to cancer drugs. In this study, we generated several monoclonal antibodies to HER3. Comparisons of their ability to degrade HER3, decrease downstream signaling, and inhibit growth of cultured cells, as well as recruit immune effector cells, selected an antibody that later emerged as the most potent inhibitor of pancreatic cancer cells grown as tumors in animals. Our data predict that anti-HER3 antibodies able to intercept autocrine and stroma–tumor interactions might strongly inhibit tumor growth, in analogy to the mechanism of action of anti-EGFR antibodies routinely used now to treat colorectal cancer patients.Growth factors and their plasma-membrane–embedded receptors regulate cellular proliferation and migration during both embryogenesis and oncogenesis (1). One example entails the epidermal growth factor (EGF) family and the corresponding human EGF receptor (HER)/ERBB family of four receptor tyrosine kinases: the EGF receptor (EGFR or ERBB1), HER2 (c-Neu or ERBB2), HER3 (ERBB3), and HER4 (ERBB4) (2). The intracellular parts of ERBB/HER receptors harbor a catalytic tyrosine kinase domain (3). After ligand binding to an ectodomain, these receptors form active homodimers or heterodimers (4–7). Unlike EGFR, HER3/ERBB3 presents very low tyrosine kinase activity (8). Nevertheless, it binds neuregulins (NRGs) and exerts profound influence on signaling pathways, primarily through dimerization with EGFR and HER2. In line with roles in cancer progression, and similarly to EGFR and HER2, mutant forms of HER3 have recently been reported in colon and gastric cancer (9).Cancer therapies that use monoclonal antibodies (mAbs) to target ERBB/HER family members are becoming a mainstay in oncology. For example, trastuzumab, which targets HER2, is currently used to treat gastric and breast cancer (10, 11). However, the majority of patients with metastatic HER2-positive breast cancer will become trastuzumab-resistant after prolonged treatment, a development significantly less common in an adjuvant or neo-adjuvant setting. It has been reported that trastuzumab-resistant tumors show elevated expression of HER3 (12), and, similarly, inhibition of HER2 using a kinase inhibitor also up-regulates HER3 (13). Likewise, HER3 has been implicated in the development of resistance to treatment with other ERBB/HER-targeted therapies (14, 15), agents blocking insulin-like growth factor receptors (16), and chemotherapeutic agents (17). For these reasons, anti-HER3 antibodies (Abs) are being developed by several laboratories, and some have reached initial clinical trials.Importantly, anticancer mechanisms of therapeutic Abs are multifactorial and incompletely understood. The involvement of Ab-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity, as well as various cellular processes such as triggering of apoptosis, blocking angiogenesis, inhibiting tumor cell proliferation, interfering with signaling cascades, and accelerating receptor internalization, have been described (18). Our own studies proposed critical involvement of the endocytic system. In particular, combinations of two mutually noncompetitive Abs (Abs against different epitopes that do not cause steric hindrance) to EGFR (19) or to HER2 (20, 21) have been shown to accelerate receptor endocytosis and inhibit tumor growth, better than either Ab alone. Furthermore, a recently completed clinical trial that combined with chemotherapy two mutually noncompetitive anti-HER2 mAbs, for the treatment of HER2-positive breast cancer (22), confirmed the clinical benefit of combining noncompetitive mAbs.Anti-HER3 agents that are being developed or are in clinical trials show promising results, yet their efficacy might be viewed, in general, as variable and rather modest (23). Hence, it is imperative to develop new agents and resolve their molecular mechanisms of action. In this study, we generated in mice a relatively broad series of anti-HER3 mAbs and examined them for the ability to both degrade HER3 and decrease downstream signaling. The new mAbs displayed a variety of biochemical and biological attributes, such as binding affinity to HER3, ability to displace NRG and block downstream signals, sort HER3 for degradation, and recruit natural killer cells. Ultimately, the Abs were tested in vitro and in tumor-bearing animals for their ability to inhibit growth of cancer cells. We focus on an especially potent tumor-inhibitory Ab that can displace NRG, robustly sort HER3 for intracellular degradation, and also recruit immune effector cells.