Genomic grade adds prognostic value in invasive lobular carcinoma

BACKGROUND

The prognostic value of histologic grade (HG) in invasive lobular carcinoma (ILC) remains uncertain, and most ILC tumors are graded as HG2. Genomic grade (GG) is a 97-gene signature that improves the prognostic value of HG. This study evaluates whether GG may overcome the limitations of HG in ILC.

METHODS

Gene expression data were generated from frozen tumor samples, and GG calculated according to the expression of 97 genes. The prognostic value of GG was assessed in a stratified Cox regression model for invasive disease-free survival (IDFS) and overall survival (OS).

RESULTS

A total of 166 patients were classified by GG. HG classified 33 (20%) tumors as HG1, 120 (73%) as HG2 and 12 (7%) as HG3. GG classified 106 (64%) tumors as GG low (GG1), 29 (17%) as GG high (GG3) and 31 (19%) as equivocal (cases not classified as GG1 or GG3). The median follow-up time was 6.5 years. In multivariate analyses, GG was associated with IDFS [HR(GG3 vs GG1) 5.6 (2.1-15.3); P < 0.001] and OS [HR(GG3 vs GG1) 7.2, 95% CI (1.6-32.2); P = 0.01].

CONCLUSIONS

GG outperformed HG in ILC and added prognostic value to classic clinicopathologic variables, including nodal status.

Urokinase-type plasminogen activator gene (PLAU) to predict clinical outcome in invasive lobular carcinoma

e21010

Background: At the molecular level invasive lobular carcinoma (ILC) is mostly composed of luminal A (LA) (≈80%) followed by luminal B (≈15%) and a small fraction of HER2-positive (≈5%) tumors (Metzger et al SABCS2011). In ILC, Genomic Grade (GG) adds prognostic information to clinico-pathological (CP) characteristics (Metzger et al ASCO 2011). In this study we sought to evaluate the prognostic value of different gene signatures/modules in patients diagnosed with LA classic ILC. Methods: Gene expression data were generated from 184 consecutive frozen tumor samples using Affymetrix U133 Plus 2.0 arrays. ILC tumors were classified into molecular subtypes using the PAM50 classifier. ILC tumors characterized as classic ILC by pahtologists and as LA by PAM50 were selected for this analysis. Invasive disease free survival (IDFS) was defined as the interval between date of surgery and date of any invasive recurrence or death. Multivariate analyses for IDFS and overall survival (OS) adjusted for age, tumor size, nodal status and chemotherapy was performed for gene signatures/modules related to proliferation, invasion, immune response and signaling pathways (IGF1, PI3K, MAPK, Src, Wnt). Results: 125 LA classic ILC tumors were identified with a median follow-up of 6.6 years (95% CI 5.6-7.6). The addition of PLAU gene expression as continous variable to CP variables yielded a significant hazard ratio (HR) for IDFS (HR= 2.1 [1.1 – 4.1], Δx2= 4.5, likelihood ratio p = 0.03) and for OS (HR = 3.6 [1.4 – 9.6], Δx2= 6.9, likelihood ratio p = 0.009). GG as a continous variable yielded a significant HR for IDFS (HR= 2.6 [1.2 – 5.7], Δx2= 6.2, likelihood ratio p = 0.01), but not for OS (HR= 2.1 [0.8 – 5.5], Δx2= 2.5, likelihood ratio p = 0.11). In contrast, IGF1, PI3K, MAPK, Src, Wnt, immune response, gene-70 and gene-76 failed failed to add signficant independent prognostic value. Conclusions: In addition to GG, PLAU adds prognostic information to CP factors in LA classic ILC and may guide future drug development in this difficult to treat BC subset. Of interest, PLAU is involved in degradation of extracellular matrix contributing to cell migration and metastasis and is a major component of a validated breast cancer biomarker (UPA/PAI1).

Gene modules and response to neoadjuvant chemotherapy in breast cancer subtypes: a pooled analysis

PURPOSE

To investigate the association between chemotherapy response and gene expression modules describing important biologic processes and druggable oncogenic pathways in breast cancer (BC) subtypes.

PATIENTS AND METHODS

We searched for publicly available gene expression studies evaluating anthracycline with or without taxane-based neoadjuvant chemotherapy and identified eight studies with 996 patients. We computed 17 gene modules and calculated odds ratios (ORs) for pathologic complete response (pCR) for one-unit increases in scaled modules with and without adjustment for clinicopathologic characteristics. Added predictive accuracy was evaluated using the area under the receiver operating characteristic curve (AUC) and integrated discrimination index (IDI). We used the false discovery rate (FDR) to adjust for multiple testing.

RESULTS

High immune module scores were associated with increased pCR probability in all BC subtypes. High module scores of chromosomal instability, phosphatase and tensin homolog (PTEN) loss, and E2F3 transcription factor were associated with increased pCR probability in estrogen receptor (ER) -negative/human epidermal growth factor receptor 2 (HER2) -negative and ER-positive/HER2-negative but not in HER2-positive tumors (interactions between HER2 and each of these modules for their association with pCR: P < .05; FDR, 0.17; trend for interaction between HER2 and PTEN). High values of insulin-like growth factor 1 activation module were associated with increased pCR probability only in ER-positive/HER2-negative tumors (interaction between insulin-like growth factor 1 and ER: P = .002; FDR, 0.03). When adding the immune module to clinicopathologic characteristics, we observed substantial increases in predictive accuracy for pCR in the HER2-positive subtype (IDI, 0.093; P = .004; increase in AUC from 0.760 to 0.836).

CONCLUSION

Different processes and pathways are associated with pCR in different BC subtypes.

Elucidating prognosis and biology of breast cancer arising in young women using gene expression profiling

PURPOSE

Breast cancer in young women is associated with poor prognosis. We aimed to define the role of gene expression signatures in predicting prognosis in young women and to understand biological differences according to age.

EXPERIMENTAL DESIGN

Patients were assigned to molecular subtypes [estrogen receptor (ER)(+)/HER2(-); HER2(+), ER(-)/HER2(-))] using a three-gene classifier. We evaluated whether previously published proliferation, stroma, and immune-related gene signatures added prognostic information to Adjuvant! online and tested their interaction with age in a Cox model for relapse-free survival (RFS). Furthermore, we evaluated the association between candidate age-related genes or gene sets with age in an adjusted linear regression model.

RESULTS

A total of 3,522 patients (20 data sets) were eligible. Patients aged 40 years or less had a higher proportion of ER(-)/HER2(-) tumors (P < 0.0001) and were associated with poorer RFS after adjustment for breast cancer subtype, tumor size, nodal status, and histologic grade and stratification for data set and treatment modality (HR = 1.34, 95% CI = 1.10-1.63, P = 0.004). The proliferation gene signatures showed no significant interaction with age in ER(+)/HER2(-) tumors after adjustment for Adjuvant! online. Further analyses suggested that breast cancer in the young is enriched with processes related to immature mammary epithelial cells (luminal progenitors, mammary stem, c-kit, RANKL) and growth factor signaling in two independent cohorts (n = 1,188 and 2,334).

CONCLUSIONS

Proliferation-related prognostic gene signatures can aid treatment decision-making for young women. However, breast cancer arising at a young age seems to be biologically distinct beyond subtype distribution. Separate therapeutic approaches such as targeting RANKL or mammary stem cells could therefore be needed.

Characterization and clinical evaluation of CD10+ stroma cells in the breast cancer microenvironment

PURPOSE

There is growing evidence that interaction between stromal and tumor cells is pivotal in breast cancer progression and response to therapy. Based on earlier research suggesting that during breast cancer progression, striking changes occur in CD10(+) stromal cells, we aimed to better characterize this cell population and its clinical relevance.

EXPERIMENTAL DESIGN

We developed a CD10(+) stroma gene expression signature (using HG U133 Plus 2.0) on the basis of the comparison of CD10 cells isolated from tumoral (n = 28) and normal (n = 3) breast tissue. We further characterized the CD10(+) cells by coculture experiments of representative breast cancer cell lines with the different CD10(+) stromal cell types (fibroblasts, myoepithelial, and mesenchymal stem cells). We then evaluated its clinical relevance in terms of in situ to invasive progression, invasive breast cancer prognosis, and prediction of efficacy of chemotherapy using publicly available data sets.

RESULTS

This 12-gene CD10(+) stroma signature includes, among others, genes involved in matrix remodeling (MMP11, MMP13, and COL10A1) and genes related to osteoblast differentiation (periostin). The coculture experiments showed that all 3 CD10(+) cell types contribute to the CD10(+) stroma signature, although mesenchymal stem cells have the highest CD10(+) stroma signature score. Of interest, this signature showed an important role in differentiating in situ from invasive breast cancer, in prognosis of the HER2(+) subpopulation of breast cancer only, and potentially in nonresponse to chemotherapy for those patients.

CONCLUSIONS

Our results highlight the importance of CD10(+) cells in breast cancer prognosis and efficacy of chemotherapy, particularly within the HER2(+) breast cancer disease.

P1-02-05: Invasive Lobular Carcinoma – A Luminal Breast Cancer Histotype Enriched for Epithelial-to-Mesenchymal Transition Features

Background: Invasive lobular carcinoma (ILC) represent the second most common breast cancer (BC) histotype, but little information is available about its molecular features. We sought to perform a comprehensive molecular classification of ILC and to investigate the molecular features that can differentiate ILC from invasive ductal carcinoma (IDC).

Methods: A consecutive series of 174 ILC tumors from three different centers with mininum 5-year follow-up was selected. Gene expression data were generated using Affymetrix U133 Plus 2.0 arrays. Data were analyzed by using frozen robust multiarray analysis (Matthew et al. 2009). ILC tumors were classified into BC molecular subtypes using the PAM50 classifier. Invasive Disease Free Survival (IDFS) was defined as the interval between the date of surgery and the date of any invasive recurrence or death. Multivariate analyses for 10-y IDFS containing classical clinico-pathologic characteristics were performed for different gene signatures, which were scaled so that 2.5 and 97.5% percentiles equal −1 and 1. A cohort of 90 IDC tumor samples, normalised with the same method, was used to compare expression data between ILC and IDC.

Results: ILCs were mainly characterized as luminal A (LA: 76%, n=133) and luminal B (LB:; 20%, n=34) followed by a minority of HER2−positive (2%, n=3), basal (1%, n=2) and normal-like (1%, n=2) based on Perou's classification. LB had inferior 10-y IDFS than LA in univariate cox regression analysis (HR = 1.99, 95% CI, 1.08−3.67, p=0.026). The EMT gene module was significantly higher expressed in ILC as compared to IDC (p &lt; 0.001). Adjusted hazard ratios (HR) for different gene modules investigated are detailed in the table below.

PD03-10: Gene Modules and Response to Neoadjuvant Chemotherapy in Breast Cancer: A Meta-Analysis

Background: We and others have shown that high expression of proliferation and immune related genes are associated with pathological complete response (pCR) after neoadjuvant chemotherapy in breast cancer (BC). Here, we performed a meta-analysis to validate these findings and to interrogate the association between pCR and several other gene expression modules beyond standard clinico-pathological characteristics in BC subtypes.

Methods: We searched for publicly available gene expression studies evaluating anthracycline ± taxane-based neoadjuvant chemotherapy. We identified 7 studies with complete genomic and clinico-pathological data including pCR totaling 788 patients. Relapse-free survival (RFS) data were available for 427 patients. We used gene expression data generated from pretreatment biopsies and computed 17 gene modules corresponding to proliferation-driven signatures, immune response, stroma activation, phosphatase and tensin homolog (PTEN) loss, chromosomal instability, and several other oncogenic pathways. We calculated odds ratios (OR) for pCR for one-unit increases in scaled modules, all adjusting for pretreatment clinico-pathological characteristics. Moreover, we tested for interactions between gene modules and ER or HER2 status for their association with pCR after adjusting for clinicopathological characteristics. We used the false discovery rate (FDR) to adjust for multiple testing.

Results: We observed pCR in 178(22.6%) of 788 patients: 112(30.1%) of 372 with ER−/HER2− BC, 41(36%) of 113 with HER2+ BC, and 25(8.2%) of 303 with ER+/HER2− BC. High values of the proliferation-driven modules were associated with increased pCR rates in ER−/HER2− (e.g. Gene70 OR=2.34, 95%CI 1.22−4.59, p=0.01, FDR=0.10) and ER+/HER2− (e.g. Gene70 OR=3.26, CI 1.13−9.60, p=0.03, FDR=0.16), but not in the HER2+ subtype (e.g. Gene70 OR=0.82, CI 0.23−2.67, p=0.74, FDR=0.86). There was a trend for interaction between proliferation-driven modules (e.g. Gene70) and HER2 status (p=0.08, FDR=0.23). Interestingly, we demonstrated a strong association between high values of immune module and increased pCR rates in the HER2+ (OR=6.58, CI 2.20−23.40, p&lt;0.01, FDR=0.03) and ER−/HER2− (OR=1.75, CI 1.12−2.76, p=0.02, FDR=0.10) but not in the ER+/HER2− subtype (OR=1.50, CI 0.63−3.42, p=0.35, FDR=0.49). Moreover, high values of AKT activation module were associated with decreased pCR rates in HER2+ (OR=0.38, CI 0.14−0.98, p=0.05, FDR=0.29) but not in the ER−/HER2− (OR=0.87, CI 0.56−1.37, p=0.56, FDR=0.68) or ER+/HER2− (OR=1.81, CI 0.65−5.30, p=0.27, FDR=0.47) subtype. Interactions between immune module and HER2 status and between AKT module and HER2 status were nominally significant (p=0.04 and p=0.05, respectively), but came with an FDR of 0.23. Of interest after a median follow-up of 3.47 years, (95% CI 3.18−3.70 years) patients with pCR had significantly longer RFS irrespective of BC subtypes (HR=0.20, 95% CI 0.08 to 0.50, p&lt;0.001).

Conclusion: Different biological processes namely proliferation, immune response and AKT activation are associated with pCR in different BC subtypes. Our results suggest that new drugs that modulate immune responses in ER−/HER2− and HER2+ BC and target AKT activation in HER2+ BC might be evaluated in these subtypes.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD03-10.

Low residual proliferation after short-term letrozole therapy is an early predictive marker of response in high proliferative ER-positive breast cancer

The gene expression grade index (GGI) is a 97-gene algorithm that measures proliferation and divides intermediate histological grade tumors into two distinct groups. We investigated the association between early changes in GGI and clinical response to neoadjuvant letrozole and compared this to Ki67 values. The paired gene expression data at the beginning and after 10-14 days of neoadjuvant letrozole treatment were available for 52 post-menopausal patients with estrogen receptor (ER)-positive breast cancer. Baseline values and changes in GGI, Ki67, and RNA expression modules representing oncogenic signaling pathways were compared to sonographic tumor volume changes after 3 months of treatment in the subsets of patients defined by high and low baseline GGI. The clinical response was observed in 80% genomic low-grade (24/30) and 59% genomic high-grade (13/22) tumors (P=0.10). Low residual proliferation after 10-14 days of neoadjuvant letrozole therapy, measured by either GGI or Ki67, was associated with sonographic response in genomic high-grade (GGI, P=0.003; Ki67, P=0.017) but not genomic low-grade (GGI, P=0.25; Ki67, P=1.0) tumors. The analysis of expression modules suggested that sonographic response to letrozole in genomic high-grade tumors was associated with an early reduction in IGF1 signaling (unadjusted P=0.018). The major conclusion of this study is that the early assessment of proliferation after short-term endocrine therapy may be useful to evaluate endocrine responsiveness, particularly in genomic high-grade ER-positive breast cancer.

DNA methylation profiling reveals a predominant immune component in breast cancers

Breast cancer is a molecularly, biologically and clinically heterogeneous group of disorders. Understanding this diversity is essential to improving diagnosis and optimizing treatment. Both genetic and acquired epigenetic abnormalities participate in cancer, but the involvement of the epigenome in breast cancer and its contribution to the complexity of the disease are still poorly understood. By means of DNA methylation profiling of 248 breast tissues, we have highlighted the existence of previously unrecognized breast cancer groups that go beyond the currently known 'expression subtypes'. Interestingly, we showed that DNA methylation profiling can reflect the cell type composition of the tumour microenvironment, and in particular a T lymphocyte infiltration of the tumours. Further, we highlighted a set of immune genes having high prognostic value in specific tumour categories. The immune component uncovered here by DNA methylation profiles provides a new perspective for the importance of the microenvironment in breast cancer, holding implications for better management of breast cancer patients.

Abstract LB-180: Epigenetic portraits of human breast cancers

Background:

Understanding the diversity of breast cancer is essential to improving diagnosis and optimising treatment. Both genetic and acquired epigenetic abnormalities participate in cancer, but information is scant on the involvement of the epigenome in breast cancer and its contribution to the complexity of the disease. Our goal was to explore the DNA methylation landscapes of phenotypically heterogeneous tumours, to relate this diversity to landscape features, and extract biological and clinical meaningful information.

Methods:

We performed comprehensive DNA methylation profiling to assess the methylomes of two independent sets of frozen breast tissue samples: a “main set” of 123 samples (4 normal and 119 infiltrating ductal carcinomas, IDCs), and a “validation set” of 125 samples (8 normal and 117 IDCs). We used the recently developed Illumina's Infinium Methylation Assay, that allows to assess the methylation status of more than 27,000 CpGs corresponding to over 14,000 genes.

Results:

Firstly, it emerged that the two major phenotypes of breast cancers determined by ER status are widely epigenetically controlled. Secondly, we have distinguished, and validated in an independent set of tumours, 6 methylation-profile-based tumour groups, some coinciding with known “expression subtypes” but also new entities that may provide a meaningful basis for refining breast tumour taxonomy. Thirdly, we showed that DNA methylation profiling can reflect the cell type composition of the tumour microenvironment. Lastly, we highlighted an unexpectedly strong epigenetic component in the regulation of key immune pathways, revealing a set of immune genes having high prognostic value in specific tumour categories.

Conclusions:

In this study, we have generated the largest and most comprehensive DNA methylation data set for human breast tumor tissues. Several novel findings and original concepts for breast cancer emerge, that previous RNA expression profiling has not highlighted. By laying the ground for better understanding of breast cancer heterogeneity and improved tumor taxonomy, the precise epigenetic portraits drawn in our work should contribute to better management of breast cancer patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-180. doi:10.1158/1538-7445.AM2011-LB-180

Abstract 839: HER2 expression occurs early in breast cancer dissemination

Background: Systemic spread of disseminated tumor cells from the primary site may occur early in breast tumorigenesis. The role of HER2 in breast cancer (BC) dissemination is not well understood. We evaluated the expression of HER2 on peripheral blood Circulating Tumor Cells (CTCs) from women with various stages of breast cancer (BC).

Methods: 81 women with preinvasive breast lesions (Atypical Ductal Hyperplasia, Lobular Carcinoma In Situ and Ductal Carcinoma In Situ), 101 women with early invasive BC and 35 women with metastatic BC were included. CTCs were defined as Cytokeratin 8,18,19+/CD45-/DAPI+ cells detected using the CellSearch® technology. Any staining for HER2 on CTCs using the CellSearch® HER2 profiling kit was considered positive. HER2 detection was calibrated through peripheral blood spiking experiments with MCF7 and SKBR3 cells.

Results: &gt; 1 CTCs/22.5mL of blood were detected in 6 of 81 (7%) women with preinvasive breast lesions (range 0-3 CTCs) and 15 of 101 (15%) women with early invasive BC (range 0-8 CTCs), whereas &gt; 1 CTCs/7.5mL of blood were detected in 17 of 35 (49%) women with metastatic BC (range 0-1160 CTCs) (p&lt;0.001). HER2 expression on CTCs was not associated with estrogen receptor (ER) and progesterone receptor (PR) expression or the histological grade of the primary tumor. In women with detectable CTCs, the ratio of HER2-positive CTCs/total CTCs was higher in HER2-positive than HER2-negative primary tumors (p=0.023). Despite a higher detection rate of CTCs, the ratio of HER2-positive CTCs/total CTCs was lower in metastatic BC (median 0.15, range 0-1.0) than in preinvasive (median 1.0, range 0-1.0) or early invasive BC (median 1.0, range 0.3-1.0) (p&lt;0.001). Similar results were observed when only HER2-negative primary tumors were considered (p=0.004).

Conclusion: This is the first report showing that HER2-positive CTCs can be detected in women with preinvasive breast lesions, further supporting the hypothesis that dissemination occurs early in breast tumorigenesis. HER2 expression on CTCs is more commonly observed in earlier stages of breast cancer, suggesting that HER2 plays an important role in early dissemination. The EORTC 90091-10093 trial will test the hypothesis that trastuzumab can eliminate HER2-positive CTCs in patients with HER2-negative early breast cancer.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 839.

Morphological observation of Y and T junctions in nanostructured boron nitride thin films

Formations of Y and T nano junctions have been observed in boron nitride films deposited on silicon substrates by plasma chemical reaction of diborane (B2H6 diluted in hydrogen) and ammonia (NH3) gases using dual frequency (microwave/radio) plasma enhanced chemical vapor deposition technique without any intentional heating of the substrates. It has been observed that these nano junctions form at a critical feed gas ratio of ammonia and diborane. We have investigated the effect of gas feed ratio R (=NH3/B2H6) in the plasma reaction chamber, keeping all other deposition parameters constant, on the morphology of boron nitride films. The deposited films are characterized by SEM, AFM, TEM and Laser Raman. For gas feed ratio, R < 100, octahedron and cubic morphologies have been observed in BN films and on increasing R to >100, size of the crystallites reduces to nanometer level. In some of our BN samples deposited at a critical value of gas ratio (R = 400), uniform Y and T junctions having bamboo like morphologies, in nanometer level, have been observed, which we wish to emphasis here as an interesting and newer observation in boron nitride films deposited by the dual frequency PECVD technique. This change in morphology exhibited by varying gas feed ratio is mainly due to excess nitrogen ions in the plasma.

Development and validation of a stability indicating HPLC assay method for cyclosporine in cyclosporine oral solution USP

The suitability of the United States Pharmacopeia (USP) assay method for analysing stressed samples of cyclosporine oral solution USP was evaluated for stability samples by analyzing cyclosporine oral solution after acid, alkali, hydrogen peroxide, heat and light treatment. Some of the degradants generated during stress testing, as well as dihydrocyclosporine A, which is a known degradant of cyclosporine A, were not adequately resolved from the cyclosporine peak and mobile phase adjustments did not improve the resolution. In addition, isocyclosporine A, another known degradant of cyclosporine, could not be quantitated as it was eluting too early with the system peaks. Therefore, a binary gradient, reverse phase, stability indicating, HPLC method for the assay of cyclosporine in cyclosporine oral solution USP has been developed and validated. Analysis of degraded samples showed that the cyclosporine A eluted as a spectrally pure peak resolved from its degradation products.

Prevention of bladder tumor formation in mice by a novel bone marrow-derived factor, reptimed

BACKGROUND

Reptimed is a novel, species-conserved, bone marrow-derived molecule which possesses anti-neoplastic activity. Previously, we established an orthotopic murine bladder tumor (MBT-2) model and reported accurate documentation of the presence and the extent of intravesical involvement of bladder tumor implants using magnetic resonance imaging (MRI) (1). Herein, we investigated the activity of exogenously administered Reptimed in the MBT-2 model.

MATERIALS AND METHODS

Intravesicular and intraperitoneal administration of Reptimed concurrently with and following transurethral tumor cell implantation was performed and MBT-2 tumor response was assessed at several time points post tumor implant.

RESULTS

Serial MRI scans of Reptimed-treated mice at days 14 to 33 post tumor transplant revealed significant inhibition of bladder tumor growth with no significant tumor growth observed by MRI on day 33 post-implant. The corresponding histological examination of the whole mount bladder sections revealed similar inhibitory effects of Reptimed with respect to the topography and depth of intravesical tumor involvement. In contrast, control, untreated bladders revealed extensive exophytic tumors with deeply invasive transitional cell carcinoma.

CONCLUSIONS

These studies demonstrate the anti-tumor effect of Reptimed and highlight its importance as a potential therapy for cancer.

Genetic correlation in otosclerosis

PURPOSE

The aim of this study was to determine the relationship of HLA typing in patients with otosclerosis.

MATERIALS AND METHODS

We used a prospective study in which HLA typing of 100 surgically confirmed otosclerosis patients were compared with age and sex matched normal individuals.

RESULTS

HLA-A3, HLA-A9, HLA-A11, and HLA-B13 were found to be significantly higher (P < .05, .01, and .01, respectively). HLA-A9 and HLA-A11 were found to be higher (P < .01) in patients with a positive family history, indicating genetic heterogenicity.

CONCLUSIONS

Higher values of HLA-A9, HLA-11, and HLA-B13 in patients with otosclerosis compared with normal individuals strongly suggests a genetic, HLA-related component.

CXCR1 and CXCR2 are rapidly down-modulated by bacterial endotoxin through a unique agonist-independent, tyrosine kinase-dependent mechanism

The expression of the seven-transmembrane domain chemokine receptors CXCR1 and CXCR2 modulates neutrophil responsiveness to the chemoattractant IL-8 and a number of closely related CXC chemokines. In the present study, we investigated the mechanism by which bacterial LPS induces the down-modulation of IL-8 responsiveness and CXCR1 and CXCR2 expression on human neutrophils. Treating neutrophils with LPS reduced IL-8R expression to 55 +/- 5% of the control within 30 min and to 23 +/- 2% within 1 h of stimulation. Furthermore, this down-modulation could not be attributed to increased concentrations of IL-8, TNF-alpha, or IL-1beta, since ELISA studies indicated that LPS-stimulated neutrophils did not release detectable amounts of these proteins before 2 h poststimulation. The tyrosine kinase (TK) inhibitors genistein and herbimycin A attenuated the LPS-mediated down-modulation of CXCR1 and CXCR2, indicating that the activation of a TK is required for LPS to mediate its effect. The effect of LPS on receptor expression paralleled the hyperphosphorylation of the protein TK p72syk. Although IL-8 induced a comparable down-modulation of CXCR1 and CXCR2, TK inhibitors did not attenuate this effect. These studies provide the first evidence of an agonist-independent, TK-dependent pathway of chemokine receptor regulation by endotoxin.

Uterus didelphys, a rare cause for tubal sterilization failure

Uterus didelphys is a rare congenital anomaly. It can result in a variety of misadventures even in the hands of an expert. The present case reports uterus didelphys as the cause for tubal sterilization failure. This is the first case of this type seen in our institution in 35 years.