Oral Cavity Cancers: Ethnic Differences in Radiotherapy Outcomes in a Majority South Asian Leicester Community

AIMS

Squamous cell carcinoma oral cavity cancers (SCCOCCs) have a higher reported incidence in South Asian countries. We sought to compare presenting stage and outcome by ethnicity in patients with SCCOCC treated with radical radiotherapy in a single centre in the UK.

MATERIALS AND METHODS

All patients with SCCOCC treated with radical radiotherapy at an oncology department in Leicester (UK) between 2011 and 2017 were identified. Baseline demographic, clinical data and 2-year treatment outcomes were reported.

RESULTS

Of the 109 patients included, 40 were South Asian and 59 were non-South Asian. South Asians had significantly poorer 2-year disease-free survival compared with non-South Asians (54.6% versus 73%, P = 0.01).

CONCLUSION

Our analysis suggests that South Asians with SCCOCC have poorer outcomes despite a younger age and similar disease characteristics. Environmental, social factors and differing biology of disease may be responsible and further research is required to inform targeted interventions.

Efficacy of Oral Colchicine and Intralesional Hyaluronidase with and without Ultrasound Therapy in the Management of Oral Submucous Fibrosis-A Comparative Study

Aim

To determine the therapeutic effect and efficacy of oral colchicine tablet and intralesional injection of hyaluronidase with and without ultrasound therapy in the clinical course of oral submucous fibrosis.

Materials and Methods

This comparative study involving 45 human participants was divided into three equal groups. The participants in group 1 received oral colchicine and intralesional hyaluronidase. The participants in group 2 received oral colchicine, intralesional hyaluronidase, and ultrasound therapy. The group 3 participants were treated with intralesional dexamethasone and hyaluronidase. Intergroup assessments were done using repeated measures of ANOVA test, where P value of <0.05 was considered as statistically significant difference.

Results

Group 2 patients had maximum improvement with respect to all the parameters.

Conclusion

Therapeutic ultrasound can be given effectively as an adjunct therapy along with conventional therapy in OSMF patients.

Abstract P5-06-14: A novel combination of a 2 gene score & TIL as a predictive Biomarker for responders to novel therapies in Indian TNBC - A population with greater proportion of TNBCs

Introduction: Triple-Negative Breast Cancer (TNBC) comprises approximately 30% of all breast cancers in Indian women. Given their aggressive nature, TNBCs have high rates of systemic metastasis and mortality with only chemotherapy available for treatment. Compelling evidence has demonstrated the prognostic value of tumor-infiltrating lymphocytes (TILs), in many cancers especially in Breast Cancer and play a critical role in tumour progression, response to therapeutics and prognosis. They are typically measured by H&E staining and immunohistochemistry for research purpose and degree of infiltrate is also known to differ among subtypes. Nonetheless, the literature regarding the types of immune cells characterizing TILs and their prognostic utility in TNBC has been conflicting for lack of accurate “functional” TIL assessments. Herein we have used a combination signature of TILs and a 2 gene immune function expression based signature to develop an unique classifier, to identify a subgroup within TNBC that has better clinical outcome, such as survival and response to treatment. Our findings also suggest a possible use of the score as a predictive biomarker for response to immune checkpoint therapy Patients and Methods: Surgically excised TNBC tumor specimens from 44 women from a single treating hospital in Bangalore, India were accessed under IERB approved protocols and assayed on nCounter® PanCancer Immune Profiling Panel which comprised of 740 genes and characterises 14 different immune cell types. Analysis using Non-negative Matrix factorization (NMF) based unsupervised clustering was done to arrive at stable subtypes characterized by different tumor microenvironments within TNBC. SSGSEA analysis was done to identify immune cell types. TILs were characterised by a pathologist on H&E sections according to guidelines from TIL working group. The Immune classifier was validated on Breast Cancer data sets from TCGA. Results: NMF followed by SAM and PAM analysis yielded 2 stable subtypes (ST1 and ST2) of proportions 59% and 41% respectively. TIL groups also were divided into Dense and Mild groups which were 52% and 48% respectively. Despite similar distributions of the groups, ST1 and ST2 had distinct survival with ST2 having poorer outcome (p=0.023) while the dense and mild TIL groups did not separate as distinct groups. On a closer examination using SSGSEA analysis with Rooney et al signature, ST1 was enriched with T-cells, Dendritic cells, MHC-class 1 and very significantly high cytolytic score (CYT), which was defined by Granzyme A and Perforin expressions, proteins secreted by cytotoxic T cells (p=0.0074). The CYT Score ranged from -35 to 170 and cutoff was based on 75th percentile. We next hypothesized that a combined score of TIL and CYT would represent a functional TIL group with high immune activity. We arrived at a CYT+TIL score based on 75th percentile cut off of CYT and 2 groups of TIL. Of the resultant four groups, TIL High-CYT high that constituted about 20% of all TNBCs indicated an elevated immune response because of their microenvironment constitution and this can be identified using our simple immune classifier. On the other hand, in the TIL-high and CYT-low group, despite lymphocyte migration, outcome was not favorable. The classifier was applied to TNBC from TCGA (n=96) and similar results seen, with ST1 and ST2 which had distinctly separate survival and had similar patterns on CYT high groups. Conclusion: We developed a simple immune classifier with 2 gene signature c and H&E slide TIL assessment for identifying a group with TNBC that can be better targeted with therapies. Our signature is predictive for selecting TNBCs which are potential responders to Immune therapies and has the potential for quick clinical adoption though it requires validation on a larger set.

Citation Format: Aruna Korlimarla, Hari PS, Jyothi S Prabhu, Chantirika Ragulan, Ravi B Diwakar, Sandhya Apachu, Maggie Cheang, Rekha V Kumar, BS Srinath, TS Sridhar, Savitha Rajarajan, Annie Alexander, Anguraj Sadanandam. A novel combination of a 2 gene score & TIL as a predictive Biomarker for responders to novel therapies in Indian TNBC - A population with greater proportion of TNBCs [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-06-14.

NGS-based profiling of key cancer genes in Indian triple-negative breast cancer patients reinforces molecular heterogeneity of the disease

Triple-negative breast cancers (TNBC) are one of the most aggressive forms of breast cancers. With poor patient outcomes, it presents a great burden on the healthcare systems. There have been some efforts to explore the genomic changes that occur in TNBCs. However, there is not enough data on Indian TNBCs. We sought to understand the mutational landscape of key cancer-associated genes in Indian TNBC patients using TruSeq Cancer Amplicon Panel. We sequenced 51 TNBC patient samples and found great heterogeneity amongst samples with respect to the genomic variants. Several previously reported including alterations in PI3K-AKT pathway genes were also identified. Likewise, we identified several novel high-frequency variants, for example, GNAQ F341S (17%), the functional role of which remains unclear. Our study lays the foundation of larger efforts needed to understand the genomic landscape of Indian TNBCs which can aid in classification and better therapeutic management of patients.

Abstract PS6-55: The prognostic utility of AR/ER ratio in young women with breast cancer

Background

World over, less than a quarter of breast cancer diagnoses are in premenopausal women. However, in India premenopausal women constitute half of all women with breast cancer in most hospital case series. Most of these women present at advanced stages with aggressive subtypes of disease and hence the high mortality.The role and utility of detecting androgen receptor (AR) expression in the different sub-types of breast cancer, especially the ones without hormone receptor expression is yet to be firmly established. Evidence from previous studies is suggestive of its beneficial role in hormone receptor positive (HR+) breast cancer. The biological function of AR on the mammary epithelium is determined by the Estrogen receptor (ER) context, in that, it is found to be anti-proliferative in ER positive tumors while it is thought to promote growth in the absence of ER activity. An interesting approach to representing this interplay is as a ratio between AR/ER expressions. As expected, the ratio has been shown to be positively correlated with better outcomes in hormone receptor cancers, mostly in postmenopausal women. The effect of a high ratio in ER negative tumors seems more complicated. In this study, we have evaluated the AR/ER ratio specifically in patients younger than 50 years in whom the estrogenic influence is dominant due to their premenopausal status.

Materials and Methods

Tumor samples from patients 50 years or younger were chosen from a larger cohort of 275 patients with median follow up of 72 months. Expression of ER and AR proteins were detected by immunohistochemistry (IHC), and the transcript levels of ESR1 and AR were determined by quantitative PCR. Relative normalized units of their gene expression were used to calculate the AR/ER ratio. A cut-off at the 3^rd quartile was used to divide tumors into categories of high and low ratios. Clinical characteristics were compared between the low and high ratio groups along with IHC subtype distribution (HR+, HER2+ and Triple negative (TNBC)). Kaplan Meier curves was used for survival analysis and Cox proportional hazard analysis model was used to calculate the hazard ratio (HR). The results were validated in METABRIC dataset.

Results

Eighty-eight (32%) patients were <50 years with a mean age of 43 years. AR/ER ratio ranged between 0.6 to 3.5 with a mean of 1.5. Sixty-six tumors were categorized as low and 22 were high based on the 3Q cut off (1.7). Clinical characters such as age, tumor size, grade, stage of disease was not different between the high and low ratio categories. Distribution of IHC subtypes among each group showed high ratio category had 64% TNBC tumors (p<0.0001). Tumors with high ratio had poor disease-free survival, (HR-2.6(95% CI-1-6.9) p-0.03). Trends in the METABRIC dataset was similar with 411(21%) patients <50 years. Ninety-seven patients with high ratio had significantly poor disease-free survival (HR-1.95 (95% CI-1.3-2.7) p-0.000).

Conclusion

Interaction between AR and ER is known to influence the AR activity and our results reiterate prognostic ability of AR/ER ratio even in young patients of breast cancer. Our results suggest androgenic influences on clinical progression of breast cancer in this age group mediated through AR, has to be examined by its level in relation to the activity of ER, particularly in hormone receptor negative breast cancers. Even more importantly, examining these influences in the context of the menopausal status might help identify subgroups of patients most likely to benefit from interventions targeted at AR.

Triple-negative breast cancers with expression of glucocorticoid receptor in immune cells show better prognosis

Background

Glucocorticoid receptor (GR) is shown to have variable frequency of expression in invasive tumors of the breast. Investigation of additional nuclear receptors like GR in receptor negative tumors like triple negative breast cancer (TNBC) may have prognostic and therapeutic significance.

Methods

Expression of GR was evaluated by immunohistochemistry in 175 tumors of invasive breast cancer with long term follow up. GR Expression was separately evaluated in invasive tumor cells, stromal cells and tumor infiltrating lymphocytes (TIL's). Staining pattern was categorised as positive when more than 1% of the cells stained in each subpopulation of cells. Disease free survival was analysed between GR positive and negative status by Kaplan Meier analysis.

Results

Of the 175 tumors, 121 (70%) were ER positive, 53 (30%) were ER negative and 29% (51) were triple negative. 74% (130/175) tumors showed expression of GR in invasive tumor cells while (84%) 147/175 had expression in TIL's. No significant difference in distribution of GR was noted between ER positive and ER negative tumors (78% vs 66%, p-0.1). Of the TNBC's 54% (28/51) and 70% (36/51) showed expression of GR in invasive tumor and TIL's respectively. Overall, GR positive tumors had significant better survival than GR negative tumors (mean survival time of 85 vs 59 months respectively, p-0.04) Contrary to the reports that GR expression in TIL's are associated with immunosuppressive activity in model systems, TNBC's with increased expression of GR in immune cells were associated with better survival (Mean survival time 74 vs 41 months, log rank test- p-0.03). TNBC tumors which were GR negative had higher lymph node metastases (p-0.04) and none of the other clinical features like age, menopausal state, tumor size and grade were different between GR positive and negative tumors within TNBC.

Conclusions

Glucocorticoids (GC) are often used to alleviate the adverse symptoms during chemotherapy. Determining the GR status is of importance due to the pro cell survival effect of the glucocorticoids mediated through GR during chemotherapy. Though GC mediated effects on chemotherapy are controversial, our results indicate favourable effects in TNBC.

miRNAs: Critical mediators of breast cancer metastatic programming

MicroRNA mediated aberrant gene regulation has been implicated in several diseases including cancer. Recent research has highlighted the role of epigenetic modulation of the complex process of breast cancer metastasis by miRNAs. miRNAs play a crucial role in the process of metastatic evolution by facilitating alterations in the phenotype of tumor cells and the tumor microenvironment that promote this process. They act as critical determinants of the multi-step progression starting from carcinogenesis all the way to organotropism. In this review, we focus on the current understanding of the compelling role of miRNAs in breast cancer metastasis.

Abstract PS4-37: A pro-tumorigenic mechanism of M2 tumor-associated macrophages (TAM) in triple-negative breast cancer

Introduction:Triple-Negative Breast Cancer (TNBC) comprises approximately 30% of all breast cancers in Indian women. Given their aggressive nature, TNBCs have high rates of systemic metastasis and mortality with only chemotherapy available for treatment. The success of immunotherapy in solid tumors has raised the hope for their utility in TNBCs as well. But only a subset of patients have a clinical response to check-point inhibitors. The cellular and molecular mechanisms that mediate the immunological response or tolerance are just beginning to be understood. Compared to ER/PR+ breast cancer, TNBC features a unique tumor microenvironment (TME) characterized by a large number of tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs). The density of TILs in and of themselves do not accurately predict response to neoadjuvant chemotherapy or survival. M2 tumor-associated macrophages (M2-TAMs) have been reported to associate with solid tumors to facilitate epithelial to mesenchymal transition (EMT), tumor invasiveness, metastasis, and resistance to therapy. In this study, we have characterized presence of M2-TAM in the TNBC immune environment by examining expression of several biomarkers. Methods:Surgically excised tumor specimens from 88 Indian women with TNBC were accessed from the longitudinal observational series of SJNAHS tissue bank under IERB approved protocols and assayed on nCounter® PanCancer Immune Profiling Panel which comprised of 740 genes and characterises 14 different immune cell types. Transcriptome analysis using Non-negative Matrix factorization (NMF) based unsupervised clustering was done to arrive at stable subtypes characterized by different tumour microenvironments within TNBC. CIEBERSORT tool was used to analyse for distribution of cell types. Identification of macrophages was done by Immunohistochemistry (IHC) for CD68 and CD163 markers in TNBCs and a control group of ER+HER2-.Results:NMF analysis with an enriched immune gene signature of 111 genes, yielded 3 subtypes (ST) (37%, 27% and 36% with relative proportions of ST1, ST2 and ST3) within the TNBC. The three subtypes had distinct survival patterns with ST1 having the best prognosis with enriched TH1 gene signature and ST3 had poorest (log rank p=0.5). On application of this gene signature to TNBC groups in METABRIC and TCGA data, similar pattern emerged with a significant survival pattern of ST 3 having the poorest outcome (p=0.005). A closer examination of ST 3 revealed a signature enriched for M2 macrophages also known as TAM. Immunohistochemistry for Pan macrophage marker CD68 and an M2 specific marker CD163 between TNBC and ER/PR+ revealed difference in the two groups was significantly different (Mann Whitney p=0.03), with TNBC exhibiting 2.4 fold higher expression of CD163. CD 68, was enriched in ST2 and ST3. CD163 which is an M2 specific marker was highest in ST3 as compared to ST 1& 2 (p=0.04). This group also correlated with signal molecules secreted by macrophages containing growth factors, cytokines and chemokines, such as TGF-β, VEGF, IL-10 and CXCL and interleukins like IL4 and IL6 suggestive of TAM recruitment and polarization. It is likely that the TAM enriched subgroup is likely to be unresponsive to PD1/PDL1 inhibitors but could be targeted by novel therapeutic strategies to directly target M2-TAM. In vitro and In vivo analysis to target M2-TAM to evaluate the response to these therapeutic compounds in cell lines as well as a mouse syngeneic model is underway.Conclusions and future directions: As a cell type within the tumor microenvironment, that promotes invasion, M2-TAMs makes an ideal therapeutic target in TNBC. In addition, this sub-type lends itself to easy identification by a simple IHC assay.

Citation Format: Aruna Korlimarla, Jyothi Prabhu, Chantirika Ragulan, Gnanapriya Shivakumar, Krisha Desai, Maggie Cheang, Srinath BS, Ravi Diwakar, Sandhya Apachu, Rekha Kumar, TS Sridhar, Savitha RajaRajan, Rohini Kaluve, Annie Alexander, Anguraj Sadanandam. A pro-tumorigenic mechanism of M2 tumor-associated macrophages (TAM) in triple-negative breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS4-37.

Abstract P4-10-12: Treatment decision making, and strategies for coping with financial stress in Indian women diagnosed with breast cancer and their families

Introduction: In spite of rapid urbanization and modernization the family remains central in the socio-cultural structure of India. The individuals are enmeshed into this unit and tend to be interlinked financially, emotionally and socially. The head of this family unit tends to be a male more often than not. As is well known, despite recent attempts by the governments at the state and centre at providing health coverage for cancer through regional cancer centres, a majority have to raise the money for cancer care by themselves. We have examined the role of the family in treatment decision making and in the strategies employed to raise the money and cope with the financial stress imposed by a diagnosis of breast cancer.

Method: 378 women with breast cancer were enrolled into a longitudinal study at first diagnosis between the years 2008-2012, at two tertiary care hospitals in Bangalore, India. The median follow up as of May 31st 2017 is 78 months with only 2% loss to follow-up over the past 8 years. Follow-up was maintained by frequent meetings between a counselling psychologist (AA) and the patient and/or a family member. The frequency of meetings was monthly during the initial treatment and then quarterly over the next 5 years. Information on demographics was collected during the treatment phase and information on the psychosocial aspects was collected in non-structured interactions subsequently. This information included details of support structure, decision making, and financial arrangements.

Results: This is a predominantly urban cohort with 80% being urban. The median age of patients at first diagnosis was 55 years. Almost all of our patients (99%) had the support of one or more family members. We analysed the pattern of decision making for treatment and in half of all cases either the husband or the son were the decision makers. In an additional 15% daughters and other relatives were the primary decision makers. Approximately a third of women made the decision concerning treatment themselves, and these women tended to be college educated (51% vs 16%) and employed (53% vs 12%).

30% of the patients met the costs incurred through medical insurance plans purchased by the family. Another quarter of patients were able to meet the costs from their savings. 45% had difficulty in finding the money for treatment and 15% took personal loans while 30% had to sell land/gold ornaments or take loans against assets of these sorts. Only (3%) discontinued the treatment due to financial difficulties. As in the case of decision making those who had the financial resources tended to be more educated (41% vs 11%), and were employed (31% vs 21%).

Conclusion: The data from a predominantly urban cohort of breast cancer enrolled between 2008-2012, supports the general belief that in India the family remains the fulcrum of an individual during crises, and not surprisingly education and employment lead to both psychological and economic emancipation of women.

Citation Format: Alexander A, Kaluve R, Prabhu JS, Korlimarla A, BS S, Manjunath S, Patil S, KS G, Sridhar TS. Treatment decision making, and strategies for coping with financial stress in Indian women diagnosed with breast cancer and their families [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-10-12.

NLScore: a novel quantitative algorithm based on 3 dimensional structural determinants to predict the probability of nuclear localization in proteins containing classical nuclear localization signals

The presence of a nuclear localization signal (NLS) in proteins can be inferred by the presence of a stretch of basic amino acids (KRKK). These NLSs are termed classical NLS (cNLS). However, only a fraction of proteins containing the cNLS pattern are transported into the nucleus by binding to importin α. Hence, there must exist, additional structural determinants that guide the appropriate interaction between putative NLSs containing cargo and importin α. Using 52 protein structures containing cNLS obtained from RCSB PDB, we assembled a training set and a validation set such that both sets were comprised of a combination of proteins with proven nuclear localization and ones that were non-nuclear. We modeled the interface between cargoes containing cNLS and importin α. We conducted rigid body docking and produced induced-fit modes by allowing both side chain and the backbone to be flexible. The output of these studies and additional determinants such as energy of interaction, atomic contacts, hydrophilic interaction, cationic interaction, and penetration of the cargo protein were used to derive a 26 parameter quantitative structure activity relationship based regression equation. This was further optimized by a step-wise backward elimination approach to derive a 15 parameter score. This NLScore was not only able to correctly classify confirmed nuclear and non-nuclear localized proteins but it was able to perform better than currently implemented algorithms like NucPred, Euk-mPLoc 2.0, cNls Mapper, and NLStradamus. Leave-one-out cross validation (LOOCV) showed that NLScore correctly predicted 78.6% and 81.6% of non-nuclear and nuclear proteins respectively. Graphical abstract NLScore: a novel quantitative algorithm based on 3 dimensional structural determinants to predict the probability of nuclear localization in proteins.

Dissecting the Biological Heterogeneity within Hormone Receptor Positive HER2 Negative Breast Cancer by Gene Expression Markers Identifies Indolent Tumors within Late Stage Disease

Hormone receptor positive (HR+) breast cancers are a heterogeneous class with differential prognosis. Although more than half of Indian women present with advanced disease, many such patients do well. We have attempted identification of biologically indolent tumors within HR+HER2- tumors based on gene expression using histological grade as a guide to tumor aggression. 144 HR+HER2- tumors were divided into subclasses based on scores derived by using transcript levels of multiple genes representing survival, proliferation, and apoptotic pathways and compared to classification by Ki-67 labeling index (LI). Clinical characters and disease free survival were compared between the subclasses. The findings were independently validated in the METABRIC data set. Using the previously established estrogen receptor (ER) down stream activity equation, 20% of the tumors with greater than 10% HR positivity by immunohistochemistry (IHC) were still found to have inadequate ER function. A tumor aggression probability score was used to segregate the remainder of tumors into indolent (22%) and aggressive (58%) classes. Significant difference in disease specific survival was seen between the groups (P = .02). Aggression probability based subclassification had a higher hazard ratio and also independent prognostic value (P < .05). Independent validation of the gene panel in the METABRIC data set showed all 3 classes; indolent (24%), aggressive (68%), and insufficient ER signaling (7%) with differential survival (P = .01). In agreement with other recent reports, biologically indolent tumors can be identified with small sets of gene panels and these tumors exist in a population with predominantly late stage disease.

HR+HER2− breast cancers with growth factor receptor–mediated EMT have a poor prognosis and lapatinib downregulates EMT in MCF-7 cells

Despite an overall good prognosis, a significant proportion of patients with hormone receptor positive human epidermal growth factor receptor 2 negative breast cancers develop distant metastases. The metastatic potential of epithelial cells is known to be regulated by tumor–stromal interaction and mediated by epithelial-to-mesenchymal transition. Hormone receptor positive human epidermal growth factor receptor 2 negative tumors were used to estimate markers of epithelial-to-mesenchymal transition, and the luminal breast cancer cell line MCF-7 was used to examine the interactions between integrins and growth factor receptors in causation of epithelial-to-mesenchymal transition. A total of 140 primary tumors were sub-divided into groups enriched for the markers of epithelial-to-mesenchymal transition (snail family transcriptional repressor 2 and integrin β6) versus those with low levels. Within the epithelial-to-mesenchymal transition+ tumors, there was a positive correlation between the transcripts of integrin β6 and growth factor receptors—human epidermal growth factor receptor 2 and epidermal growth factor receptor. In tumors enriched for epithelial-to-mesenchymal transition markers, patients with tumors with the highest quartile of growth factor receptor transcripts had a shorter disease-free survival compared to patients with low growth factor receptor expression by Kaplan–Meier analysis (log rank, p = 0.03). Epithelial-to-mesenchymal transition was induced in MCF-7 cells by treatment with transforming growth factor beta 1 and confirmed by upregulation of SNAI1 and SNAI2 transcripts, increase of vimentin and integrin β6 protein, and repression of E-cadherin. Treatment of these cells with the dual-specificity tyrosine-kinase inhibitor lapatinib led to downregulation of epithelial-to-mesenchymal transition as indicated by lower levels of SNAI1 and SNAI2 transcripts, integrin αvβ6, and matrix metalloproteinase 9 protein. The results suggest that synergistic interactions between growth factor receptors and integrin β6 could mediate epithelial-to-mesenchymal transition and migration in a subset of luminal breast cancers and lapatinib might be effective in disrupting this interaction.

Abstract P4-07-10: Epithelial mesenchymal transition associated with high miR-221 and integrin β6 leads to poor prognosis in hormone receptor positive HER2 negative breast cancers

Background: MicroRNA mediated molecular alterations are involved in the initiation and progression of cancer. Altered expression of multiple microRNAs is associated with endocrine resistance in hormone receptor positive HER2 negative (HR+/HER2-ve) cancer. The role of miR-221 in inducing epithelial to mesenchymal transition (EMT) is well documented especially in cell line model systems. However, the detailed mechanism of specific microRNAs in intrinsic and acquired resistance to endocrine therapy needs to be worked out. In addition, more needs to be done in the documentation of these mechanisms in human breast cancer specimens with complete clinical documentation and long-term follow-up. In this study, we have evaluated the clinical significance of miR-221 and its mechanistic role in EMT using human specimens and cell line models.

Materials and Methods: Formalin fixed paraffin embedded tumor from 129 HR+/HER2-ve breast cancer patients with a median follow up of 63 months were used for estimation of miR-221 by quantitative real time PCR. Expression levels of genes which are direct targets of miR-221 and related genes in EMT were analysed from these tumors. Survival between miR-221 high and low groups was compared by Kaplan Meier survival curves and prognostic relevance was estimated by Cox proportional hazard model.

Cell line experiments to investigate the role of miR-221 in inducing EMT through integrin β6 are underway in both wild type and tamoxifen resistant MCF-7 cell lines (A gift from Prof Ben Ho Park, Johns Hopkins University School of Medicine).

Results: A significant elevated level of miR-221 was observed in small proportion (14%) of HR+/HER2-ve tumors. miR-221 expression had an inverse correlation with both ER protein and ESR1 mRNA levels within HR+/HER2-ve tumors. Tumors with high levels of miR-221 showed significantly higher expression of integrin β6 which is a robust marker of EMT. Patients with high expression of miR-221 had a poorer survival in Kaplan Meier analysis.

Results of interrogation of EMT mediated through integrin related pathways involving miR-221 in cell line models will be presented.

Discussion: The association between miR-221 and integrin β6 in HR+/HER2-ve breast cancer with endocrine resistance suggests a potential link between an epigenetic regulator and a mediator of tumor-stromal interaction. The other mediators involved in this pathway are being investigated. miR-221 could be potentially used as a marker for identification of a poor prognostic subtype within HR+/HER2-ve breast cancers.

Citation Format: Prabhu JS, Kaul R, Korlimarla A, Desai K, Gangadharan C, Rajarajan S, Nair MG, Alexander A, Kaluve R, Manjunath S, Correa M, Prasad MSN, Patil S, Srinath BS, Sridhar TS. Epithelial mesenchymal transition associated with high miR-221 and integrin β6 leads to poor prognosis in hormone receptor positive HER2 negative breast cancers [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-07-10.

Abstract P4-06-11: Differential regulation of microRNAs and integrins influences metastatic potential: Comparison between locally invasive BT-474 and metastatic MDA-MB-231 xenografts

Background: Generation of BT-474 and MDA-MB-231 xenografts in immunocompromised mice provides one means of dissecting the molecular events involved in local invasion versus distant metastasis. Recently, Glunde et al have shown an interdependence of genes involved in cell-cell and cell-matrix adhesion (E-cadherin and integrin β1) and extra-cellular matrix degradation (MMP-2 and 9) in allowing cells to metastasize. Further, Fite el al have identified a set of microRNAs (miRs) up-regulated by E-cadherin (a pre-EMT marker) and down-regulated by Vimentin (post-EMT marker) in acquiring an invasive phenotype. We have performed a detailed analysis of integrins, matrix metallo-proteases and key miRs to better understand the molecular events underlying these disparate behaviours.

Methods: We injected BT-474 (N=5) and MDA-MB-231 (N=5) cells orthotopically into SCID mice. Xenografts were assessed for local growth rate and monitored for distant metastasis. The implanted tumors as well as the distant metastatic foci were harvested. Markers involved in local invasion, distant metastasis and tumor-stroma interactions including miRs were compared between BT-474 and MDA-MB-231 cell lines and their xenografts by q-RT-PCR, immunofluorescence and immunohistochemistry.

Results: As expected BT-474 xenografts showed a higher rate of tumor growth when compared to MDA-MB-231. Histological examination of BT-474 tumors confirmed only locally invasive tumor growth with infiltrated blood capillaries and vessels; no macro and microscopic metastases were observed in the organs collected. On the contrary, MDA-MB-231 xenografts showed highly undifferentiated tumor growth and frank lung metastasis and extra-pulmonary tumor growth in one of the five mice injected despite slow rate of local growth. Expression of matrix metalloproteases – MMP-2 & 9 was more than 30 fold upregulated in MDA-MB-231 xenografts as compared to BT-474. Elevated level of E-cadherin was observed in BT-474 but was absent in MDA-MB-231.

The most interesting differences were seen in the levels of miRs and cell-surface integrins. High levels of miR-18a, miR-93 and miR-182 were observed in BT-474 implants when compared to MDA-MB-231 which had a much lower level of these miRs. On the contrary, higher levels of integrin β3, and β1 were observed in MDA-MB-231 tumors when compared to BT-474. Integrin β6 was absent in both. The reciprocal relationship between these markers is being examined and compared between locally invasive tumors and metastatic triple negative breast cancers from our case series of human specimens (N=250).

Conclusion: miRs and integrins known to be involved in invasion are differentially regulated in tumors that are locally invasive compared to ones with distant metastasis. The level of the key targets of these miRs as well as additional integrins is being examined. Understanding the epigenetic regulations leading to metastasis via tumor-stroma interaction might help in discerning differential tumor behaviour.

Citation Format: Lawrence PV, Desai K, Prabhu JS, Korlimarla A, Nair MG, Sridhar TS. Differential regulation of microRNAs and integrins influences metastatic potential: Comparison between locally invasive BT-474 and metastatic MDA-MB-231 xenografts [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-06-11.

Data on alteration of hormone and growth factor receptor profiles over progressive passages of breast cancer cell lines representing different clinical subtypes

Human breast cancers are a highly heterogeneous group of tumours consisting of several molecular subtypes with a variable profile of hormone, growth factor receptors and cytokeratins [1]. Here, the data shows immunofluorescence profiling of four different cell lines belonging to distinct clinical subtypes of breast cancer. Post revival, the cell lines were passaged in culture and immunophenotyping was done for ER, HER-2, AR and EGFR. Data for the markers from early passage (5th) through passages as late as 25 for the different cell lines is presented.

The ethics of research on stored biological samples: outcomes of a Workshop

Research is often conducted using laboratory samples and data. The ethical issues that arise in a study involving residual samples are considerably different from those arising in a prospective study. Some of these ethical issues concern the risks to confidentiality, individual autonomy, trust in and credibility of the researcher or the research, commercialisation and even the nomenclature involved.

High expression of integrin β6 in association with the Rho-Rac pathway identifies a poor prognostic subgroup within HER2 amplified breast cancers

Integrin αvβ6 is involved in the transition from ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) of the breast. In addition, integrin β6 (ITGB6) is of prognostic value in invasive breast cancers, particularly in HER2+ subtype. However, pathways mediating the activity of integrin αvβ6 in clinical progression of invasive breast cancers need further elucidation. We have examined human breast cancer specimens (N = 460) for the expression of integrin β6 (ITGB6) mRNA by qPCR. In addition, we have examined a subset (N = 147) for the expression of αvβ6 integrin by immunohistochemistry (IHC). The expression levels of members of Rho–Rac pathway including downstream genes (ACTR2,ACTR3) and effector proteinases (MMP9,MMP15) were estimated by qPCR in the HER2+ subset (N = 59). There is a significant increase in the mean expression of ITGB6 in HER2+ tumors compared to HR+HER2‐ and triple negative (TNBC) subtypes (P = 0.00). HER2+ tumors with the highest levels (top quartile) of ITGB6 have significantly elevated levels of all the genes of the Rho–Rac pathway (P‐values from 0.01 to 0.0001). Patients in this group have a significantly shorter disease‐free survival compared to the group with lower ITGB6 levels (HR = 2.9 (0.9–8.9), P = 0.05). The mean level of ITGB6 expression is increased further in lymph node‐positive tumors. The increased regional and distant metastasis observed in HER2+ tumors with high levels of ITGB6 might be mediated by the canonical Rho–Rac pathway through increased expression of MMP9 and MMP15.

Abstract P4-07-09: An approach to the identification of tumors driven by HER2 using the integrated activity of oncomiR miR-21 along with HER2 enriched genes

Introduction: The initial identification of HER2 as a driver in a subset of breast cancers was at the level of DNA (amplification), and subsequently noted at the level of transcripts and protein as well. However, the clinical selection of patients for treatment with Trastuzumab, has been through either IHC (protein) or FISH (DNA amplification) and not through transcript abundance. Interestingly, in most studies that have estimated transcript abundance in primary tumors, the proportion of patients that demonstrate increased transcript levels (termed HER2 Enriched) have tended to be slightly larger than the clinical HER2+ category.

A more clinically useful measure might be proof of HER2 downstream activity that might help separate tumors being driven significantly by HER2 from ones where its role is supportive. One of the many consequences of HER2 over-expression is activation of the oncomiR, miR-21 via the MAPK pathway. miR-21 in turn is known to epigenetically regulate multiple targets including the tumor suppressors PTEN and PDCD4. While these molecular mechanisms have been demonstrated convincingly in breast cancer cell lines, clinical studies of these alterations in large numbers are yet to be reported. In this study we have examined the relationship between clinical HER2 positivity and miR-21 levels in 124 surgically excised breast cancer specimens.

Methods: We selected 124 surgically excised specimens of primary breast cancers from our cohort that by HER2 immunohistochemistry (IHC) comprised 42 positive, 62 negative and 20 equivocal. Relative abundance of miR-21 was assessed using a TaqMan qRT-PCR, with normalization by RNU48. Relative transcript abundance of a set of 6 genes (HER2, GRB7, MLN64 and 3 reference genes) were evaluated by SYBR Green real time qPCR.

Results: The majority of tumors that were clinically HER2+ over expressed miR-21. A concordance with an AUC of 96% at 100% sensitivity and 85% specificity was noted. There is a highly significant differential expression of miR-21 between HER2 positive, negative and equivocal samples (P &lt; 0.0001).

HER2 enriched score determined by using the expression levels of 3 genes (HER2, GRB7, MLN64) identified 35% (44/124) of the samples to be HER2 enriched. 72% of these (32/44) were also clinical HER2 positive by IHC. As expected, miR-21 was significantly over expressed in these tumors as well (P&lt;0.0001).

To identify all samples which might show HER2 downstream activity, a logistic regression model was built using expression of miR-21, HER2, MLN64 and GRB7 as the determinants of HER2 status. The best fitting model classified 91% (38/42) of HER2 +, 95% (59/62) of the HER2 negative accurately with 94% specificity and an AUC of 0.96. The model helped identify 10% of clinical HER2 negative samples (6/20 equivocal & 3/62 HER-2 negative) to have a high probability of being HER2+.

Conclusion: Identification of HER2+ tumors with evidence of downstream activity may help identify patients with tumors being driven significantly by HER2 from ones where its role is supportive. The possibility of targeting miR-21 raises the tantalizing prospect of effecting change by altering the epigenetic regulation of multiple targets including tumor-suppressors.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-07-09.

Abstract P6-08-12: Gains in women’s education has not led to commensurate gains in seeking health-care early in breast cancer patients in urban India

Introduction:

Breast cancer is the leading cancer diagnosed in urban Indian women. Historically the proportion of women presenting with advanced disease has been in excess of 50% at most regional cancer centres. The past 20 years has witnessed rapid economic growth and urbanization with significant gains in women's education and access to health. However, it is not clear if this has translated to earlier seeking of care in the educated.

The aim of this study was to examine if higher education (College) was a determinant in the time of seeking first medical consultation, and whether there were significant differences between women under the age of 40 versus women over 60 years old at the time of diagnosis.

Methods:

The data for analysis were obtained from a prospective longitudinal observational study conducted between 2008-2013 at a medical teaching hospital and a tertiary specialized cancer care centre. A total of 460 patients have been enrolled so far. All patients provided informed consent and the study has been reviewed and approved by the institutional ethics committees at these institutions. We have collected from the patients and their medical records information about their age at diagnosis, educational level, stage of disease, histopathology reports and clinical details.

Results:

Data from 194 patients have been used for the analysis. Patients were divided into one group of &lt; = 40Y of age (Group I, N = 58) and the second of &gt; = 60 years of age (Group II, N = 136). Mean age at presentation for the groups was 35 and 68 years respectively. As expected almost 1.5 times as many women under the age of 40 (36%) were college educated compared to the women over 60 (22%) (p = 0.05). The proportion of LABC in the two groups was not different with group I having 27% and group II 25%. The proportion of older women with LABC and a college degree was 20%. However, rather than the expected decrease in proportion of women with high education and LABC, 31% of young women with LABC had a college degree. LABC in the college educated was not different in the group I when compared to group II. (p = 0.39).

Conclusion:

The determinants of seeking health care are complex and influenced by a variety of factors including socio-economic status, access to health care, education, cultural beliefs, and personal preferences. While urban India's steady economic growth has been highlighted by the scholarly as well as the lay press, the data presented here suggest that there is not an automatic and linear transfer between education, economics and healthcare seeking behaviours. We suggest that while a lot of attention has been paid to awareness and screening, we may need to focus on local cultural factors, and perhaps provide support from female counsellors and care providers as critical components of attempting to bring our women to the hospital at the earliest.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-08-12.

NPHS2 mutations in Indian children with sporadic early steroid resistant nephrotic syndrome

We examined the frequency and spectrum of podocin NPHS2 mutations in Indian children with sporadic steroid resistant nephrotic syndrome (SRNS). Of 25 children screened, only one (4%) had a pathogenic mutation resulting in a stop codon. The allele and genotype frequencies of the four known single nucleotide polymorphisms detected in the cohort were similar to that of controls. This finding emphasizes the need to screen for mutations in other genes involved in the pathogenesis of SRNS.

Evaluation of High Resolution Melting analysis as an alternate tool to screen for risk alleles associated with small kidneys in Indian newborns

BACKGROUND

Single nucleotide polymorphisms (SNPs) are the most common forms of sequence variations in the human genome. They contribute to the human phenotypic spectrum and are associated with variations in response to pathogens, drugs and vaccines. Recently, SNPs in three human genes involved in kidney development (RET, PAX2 and ALDH1A2) have been reported to be associated with variation in renal size and function. These known SNPs could potentially be used in the clinic as markers for identifying babies who may have smaller kidneys and permit close follow up for early detection of hypertension and acquired renal dysfunction. The aim of this study was to evaluate the use of High Resolution Melting technique (HRM) as a tool for detecting the known SNPs in these three genes in comparison to sequencing which is the gold standard.

METHODS

High resolution melting analysis was performed on 75 DNA samples that were previously sequenced for the known polymorphisms in RET (rs1800860), PAX2 (rs11190688) and ALDH1A2 (rs7169289) genes. The SNPs were G > A transitions in RET and PAX2 and A > G in ALDH1A2 gene. A blinded assessment was performed on these samples for evaluation of the HRM technique as compared to sequencing.

RESULTS

Each variant had a unique melt curve profile that was reproducible. The shift in melting temperature (Tm) allowed visual discrimination between the homozygous alleles (major and minor) in all three genes. The shape of the melting curve as compared to the major allele homozygous curve allowed the identification of the heterozygotes in each of the three SNPs. For validation, HRM was performed on 25 samples for each of the three SNPs. The results were compared with the sequencing results and 100% correct identification of the samples was obtained for RET, PAX2, and ALDA1H2 gene.

CONCLUSION

High Resolution Melting analysis is a simple, rapid and cost effective technique that could be used in a large population to identify babies with the risk alleles. These high risk children could be followed up for early detection of hypertension and acquired renal dysfunction.

A Decision Table for the Cloud Computing Decision in Small Business

An issue facing the manager of a small business is the use of cloud computing to meet the information technology (IT) needs of the firm. These businesses typically have limited in-house IT capabilities and often outsource much of their IT. This paper discusses this rapidly evolving technology and provides a framework for businesses to decide on harnessing the power of cloud computing. It recommends the appropriate decision based on the way in which IT is currently used in the enterprise and future needs to meet competitive challenges. The potential cost savings, technology insurance from cloud computing, and security risks are discussed and factored into the decision.

Estrogen Receptor Negative Breast Cancer in India: Do We Really Have Higher Burden of this Subtype?

ER negative and Triple negative breast cancers carry a poorer prognosis and are not amenable to hormone therapy. It has been previously observed that Indian patients with breast cancer have a higher tendency to have these tumours. Whether this is due to inherent biological differences in the tumours of our patients is a matter of much debate. We have analysed 250 patients of breast cancer for hormone receptor status, compared them with western series, and attempted to support the hypothesis that the higher ER negativity and triple negativity is indeed due to different tumour biology.

Paraquat induces oxidative stress, neuronal loss in substantia nigra region and parkinsonism in adult rats: neuroprotection and amelioration of symptoms by water-soluble formulation of coenzyme Q10

Background

Parkinson's disease, for which currently there is no cure, develops as a result of progressive loss of dopamine neurons in the brain; thus, identification of any potential therapeutic intervention for disease management is of a great importance.

Results

Here we report that prophylactic application of water-soluble formulation of coenzyme Q₁₀ could effectively offset the effects of environmental neurotoxin paraquat, believed to be a contributing factor in the development of familial PD. In this study we utilized a model of paraquat-induced dopaminergic neurodegeneration in adult rats that received three weekly intra-peritoneal injections of the herbicide paraquat. Histological and biochemical analyses of rat brains revealed increased levels of oxidative stress markers and a loss of approximately 65% of dopamine neurons in the substantia nigra region. The paraquat-exposed rats also displayed impaired balancing skills on a slowly rotating drum (rotorod) evidenced by their reduced spontaneity in gait performance. In contrast, paraquat exposed rats receiving a water-soluble formulation of coenzyme Q₁₀ in their drinking water prior to and during the paraquat treatment neither developed neurodegeneration nor reduced rotorod performance and were indistinguishable from the control paraquat-untreated rats.

Conclusion

Our data confirmed that paraquat-induced neurotoxicity represents a convenient rat model of Parkinsonian neurodegeneration suitable for mechanistic and neuroprotective studies. This is the first preclinical evaluation of a water-soluble coenzyme Q₁₀ formulation showing the evidence of prophylactic neuroprotection at clinically relevant doses.

Concomitant (without adjuvant) temozolomide and radiation to treat glioblastoma: a retrospective study

Between November 2004 and August 2006 we treated 35 patients with concomitant temozolomide (TMZ) and radiotherapy. Twelve patients had very large or multicentric glioblastoma multiforme with a poor performance status and received TMZ plus radiation doses of 45-50.4 Gy. The median survival of these patients was only 3.8 months. Twenty-three patients would have been eligible for randomisation in the European Organisation for Research and Treatment of Cancer/National Cancer Institute of Canada (EORTC/NCIC) trial comparing combined and adjuvant TMZ plus radiation against radiotherapy alone. This group of patients received 60 Gy in 30 fractions plus concomitant TMZ (75 mg/m(2)) but no adjuvant chemotherapy. At a median follow-up of 26 months, five of 23 patients are alive. The median survival time was 17 months (1.43 years; 95% confidence interval 0.96-1.55). Eighteen per cent were alive at 2 years. Toxicity from TMZ was infrequent. This series adds to indirect evidence that the concomitant rather than the adjuvant is the more efficacious part of the EORTC/NCIC schedule for this type of patient. Further trials should include a concomitant chemoradiotherapy regimen as well as concomitant plus adjuvant chemotherapy.

Assessment of microsatellite instability in colorectal carcinoma at an Indian center

AIM

The purpose of the present study was to evaluate the frequency of microsatellite instability (MSI) in colorectal cancers in an Indian cohort.

MATERIALS AND METHODS

Paraffin embedded tissue samples of colorectal cancers from 46 patients were assessed for mismatch repair protein expression (hMLH1 and hMSH2) by immunohistochemistry. Subsequently, MSI analysis was done after PCR amplification of five Bethesda markers.

RESULTS

Amongst 46 cases studied, only 5 patients (10.8%) showed MSI. Out of these, two (4.3%) had high microsatellite instability (MSI-H) and three (6.5%) showed low microsatellite instability (MSI-L). Out of 46 cases, 41 were microsatellite stable (MSS). In the 46 cases tested by immunohistochemistry, 7 (15.7%) showed the absence of hMLH1 and 1 case showed the absence of hMSH2.

CONCLUSION

Our study indicates a similar rate of incidence of MSI in colorectal cancers in the Indian cohort compared to the West (10-15%) despite lower incidence of colorectal cancers and predominance of rectosigmoid tumors in the Indian population.

Rheological observation of glassy dynamics of dilute polymer solutions near the coil-stretch transition in elongational flows

It has long been conjectured that the macroscopic dynamics of dilute polymer solutions may exhibit a glasslike slowdown caused by ergodicity breaking, in the vicinity of the coil-stretch transition in elongational flows. We report experimental observations using a filament stretching rheometer that confirm the existence of such glassy states. It is observed that different time-dependent elongational strain-rate profiles lead to a pronounced history dependence and aging effects within a narrow range of strain rates. The results have a direct bearing on the analysis and design of processes employing dilute polymer solutions, such as ink-jet printing, surface coating, and turbulent-drag reduction.