Expression of Cyclin D1 in Urothelial Carcinoma of Urinary Bladder and its Association with Tumour Grade

Urothelial carcinoma (UC) is the most common malignancy of urinary bladder. It is the 9th leading cause of death worldwide and second most common genitourinary malignancy among male. Incidence is increasing in developing countries like Bangladesh. About 80% of patients are found between 50 to 80 years of age. It is 3-4 times more common in male than in female. Determination of therapeutic strategy and prediction of progression of urothelial carcinoma is a major clinical challenge. Treatment of urothelial carcinoma still now mostly depends on pathological stages. Amplification or genomic alteration of Cyclin D1 (a proto-oncogene) may cause protein overexpression which is frequently realized as a clonal pathology in various human neoplasms including bladder cancer. Evaluation of Cyclin D1 expression is promising for guiding therapeutic strategies, risk stratification and prediction of tumor progression. The aim of the study was to determine the expression of Cyclin D1 in urothelial carcinoma of urinary bladder and its association with tumour grade. This cross-sectional observational study was conducted in Department of Pathology, Dhaka Medical College, Dhaka, Bangladesh from July 2019 to June 2021. Histomorphologically diagnosed 51 urothelial carcinomas were included. Sections were stained with hematoxylin and eosin. Immunostaining with Cyclin D1 antibody was also done. Relevant information was collected and recorded in a predesigned data sheet. Statistical analysis was carried out as required. Mean age ±SD was 57.8±10.55 years. Male female ratio was 4.6:1. In this study 39(76.5%) patients were smoker. Regarding clinical presentations 36(70.6%) patients presented with painless hematuria alone. Lateral wall (64.7%) was the most frequent tumor location. Among 51 cases, 38(74.5%) cases were high grade urothelial carcinoma (HGUC) and 13(25.5%) cases were low grade urothelial carcinoma (LGUC). Considering Cyclin D1 expression, most of the LGUC cases showed high level of expression by both percentage (84.6%) and intensity (84.6%). Most of the HGUC cases showed low level of expression by both percentage (63.2%) and intensity (60.5%). Cyclin D1 showed significant inverse association with HGUC (p<0.05). In urothelial carcinoma of urinary bladder, Cyclin D1 expression was decreased with increasing grade of the tumor. Cyclin D1 expression was inversely associated with tumour grade.

Single-cell and bulk transcriptome sequencing identifies two epithelial tumor cell states and refines the consensus molecular classification of colorectal cancer

The consensus molecular subtype (CMS) classification of colorectal cancer is based on bulk transcriptomics. The underlying epithelial cell diversity remains unclear. We analyzed 373,058 single-cell transcriptomes from 63 patients, focusing on 49,155 epithelial cells. We identified a pervasive genetic and transcriptomic dichotomy of malignant cells, based on distinct gene expression, DNA copy number and gene regulatory network. We recapitulated these subtypes in bulk transcriptomes from 3,614 patients. The two intrinsic subtypes, iCMS2 and iCMS3, refine CMS. iCMS3 comprises microsatellite unstable (MSI-H) cancers and one-third of microsatellite-stable (MSS) tumors. iCMS3 MSS cancers are transcriptomically more similar to MSI-H cancers than to other MSS cancers. CMS4 cancers had either iCMS2 or iCMS3 epithelium; the latter had the worst prognosis. We defined the intrinsic epithelial axis of colorectal cancer and propose a refined ‘IMF’ classification with five subtypes, combining intrinsic epithelial subtype (I), microsatellite instability status (M) and fibrosis (F).

A single-cell transcriptomic analysis of 63 patients with colorectal cancer classifies tumor cells into two epithelial subtypes. An improved tumor classification based on epithelial subtype, microsatellite stability and fibrosis reveals differences in pathway activation and metastasis.

Integrative Profiling of T790M-Negative EGFR-Mutated NSCLC Reveals Pervasive Lineage Transition and Therapeutic Opportunities

PURPOSE

Despite the established role of EGFR tyrosine kinase inhibitors (TKIs) in EGFR-mutated NSCLC, drug resistance inevitably ensues, with a paucity of treatment options especially in EGFR ^T790M-negative resistance.

EXPERIMENTAL DESIGN

We performed whole-exome and transcriptome analysis of 59 patients with first- and second-generation EGFR TKI-resistant metastatic EGFR-mutated NSCLC to characterize and compare molecular alterations mediating resistance in T790M-positive (T790M⁺) and -negative (T790M^-) disease.

RESULTS

Transcriptomic analysis revealed ubiquitous loss of adenocarcinoma lineage gene expression in T790M^- tumors, orthogonally validated using multiplex IHC. There was enrichment of genomic features such as TP53 alterations, 3q chromosomal amplifications, whole-genome doubling and nonaging mutational signatures in T790M^- tumors. Almost half of resistant tumors were further classified as immune^hot, with clinical outcomes conditional on immune cell-infiltration state and T790M status. Finally, using a Bayesian statistical approach, we explored how T790M^- and T790M⁺ disease might be predicted using comprehensive genomic and transcriptomic profiles of treatment-naïve patients.

CONCLUSIONS

Our results illustrate the interplay between genetic alterations, cell lineage plasticity, and immune microenvironment in shaping divergent TKI resistance and outcome trajectories in EGFR-mutated NSCLC. Genomic and transcriptomic profiling may facilitate the design of bespoke therapeutic approaches tailored to a tumor's adaptive potential.

Abstract 3990: Tri-compartment (epithelial, immune, fibroblast) patient-derived models of the tumor microenvironment from an immuno-genomic profiled cohort of early stage colorectal cancers

Background: Immunotherapy has so far had limited success in colorectal cancer (CRC), with its efficacy restricted to a subset of microsatellite instability high (MSI-H) tumors. A comprehensive interrogation of the CRC tumor immune microenvironment (TME) is urgently needed. We present here an ongoing multi-platform study on early stage colon and rectal cancers, where immuno-genomic profiling of tumors and patient-derived cell models of tumor epithelia, cancer-associated fibroblasts and tumor-infiltrating lymphocytes (TIL) complement each other, with opportunities for mutual cross-validation between experimental and bioprofiling data.

Methods: At the time of writing, 21 of a planned 50 early stage CRC patients have been recruited. Surgically resected tumors are processed for 4 broad classes of analyses: 1) Bulk tissue profiling by RNA and whole exome sequencing; 2) High resolution protein and transcriptome analysis comprising scRNA-seq and flow cytometry/CyToF; 3) H&E analysis and multiplex immunohistochemistry for TME-specific proteins; 4) Culture of epithelial, fibroblast, and TIL lines, and generation of patient-derived xenografts for functional studies.

Results: Four tumors were MSI-H and 17 were microsatellite stable (MSS), with 1 POLE-mutant MSS patient harboring over 6000 mutations. Bulk genomics analysis revealed the most common mutations to be in TP53, APC, MUC17, and TGFBR2. The most frequently altered pathways were WNT, followed in order by p53, TGFβ, PI3K, and RAS-MAPK. scRNA-seq and flow cytometry/CyToF analyses are being performed to examine immune phenotypes, mediators of cell migration, and immune suppressive populations, which complement data on transcriptomic profile, histopathology, and spatial localization of TME cellular components. Of the 3 cultured cell types, 16 patients have lines of at least one cell compartment established in vitro. Characteristics of individual models will be reported at the meeting. Establishing the 3 cultured cell types from the same patient will enable us to develop an autologous patient-derived co-culture system to evaluate all 3 pairwise interactions, including TIL cytotoxicity toward epithelial cells, mutual modulation by fibroblast and epithelial cells in co-culture and their phenotypic alterations, and fibroblast regulation of TIL cytotoxic function. Autologous co-cultures with all 3 cell types are also planned.

Conclusions: The generation of well-annotated multi-platform profiling data from CRC tumors, complemented by matched tri-compartment patient-derived cell cultures, enables mutual cross-validation between experimental models of the TME and bioprofiling data.

Citation Format: Lindsay H. Kua, Fiona Y. Lee, Christine L. Eng, Harini Srinivasan, Rahul Nahar, Janice H. Oh, Nicole Ann L. Gunn, Kai Xian Thng, Ashley S. Yong, Adrian C. Sim, Rebecca Lim, Nicole Boo, Simeen Malik, Michael T. Wong, Tze Guan Tan, Shu Wen S. Ho, Shirleen Soh, Wan Jun Lim, Macalinao Dominique Camat, Joe P. Yeong, Clarinda W. Chua, Wei Qiang Leow, Ramanuj DasGupta, Si-Lin Koo, Lewis Hong, Brian Henry, Tony K. Lim, Iain B. Tan. Tri-compartment (epithelial, immune, fibroblast) patient-derived models of the tumor microenvironment from an immuno-genomic profiled cohort of early stage colorectal cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3990.

Genomic landscape of lung adenocarcinoma in East Asians

Lung cancer is the world's leading cause of cancer death and shows strong ancestry disparities. By sequencing and assembling a large genomic and transcriptomic dataset of lung adenocarcinoma (LUAD) in individuals of East Asian ancestry (EAS; n = 305), we found that East Asian LUADs had more stable genomes characterized by fewer mutations and fewer copy number alterations than LUADs from individuals of European ancestry. This difference is much stronger in smokers as compared to nonsmokers. Transcriptomic clustering identified a new EAS-specific LUAD subgroup with a less complex genomic profile and upregulated immune-related genes, allowing the possibility of immunotherapy-based approaches. Integrative analysis across clinical and molecular features showed the importance of molecular phenotypes in patient prognostic stratification. EAS LUADs had better prediction accuracy than those of European ancestry, potentially due to their less complex genomic architecture. This study elucidated a comprehensive genomic landscape of EAS LUADs and highlighted important ancestry differences between the two cohorts.

Clonal MET Amplification as a Determinant of Tyrosine Kinase Inhibitor Resistance in Epidermal Growth Factor Receptor-Mutant Non-Small-Cell Lung Cancer

PURPOSE

Mesenchymal epithelial transition factor ( MET) activation has been implicated as an oncogenic driver in epidermal growth factor receptor ( EGFR)-mutant non-small-cell lung cancer (NSCLC) and can mediate primary and secondary resistance to EGFR tyrosine kinase inhibitors (TKI). High copy number thresholds have been suggested to enrich for response to MET inhibitors. We examined the clinical relevance of MET copy number gain (CNG) in the setting of treatment-naive metastatic EGFR-mutant-positive NSCLC.

PATIENTS AND METHODS

MET fluorescence in situ hybridization was performed in 200 consecutive patients identified as metastatic treatment-naïve EGFR-mutant-positive. We defined MET-high as CNG greater than or equal to 5, with an additional criterion of MET/centromeric portion of chromosome 7 ratiο greater than or equal to 2 for amplification. Time-to-treatment failure (TTF) to EGFR TKI in patients identified as MET-high and -low was estimated by Kaplan-Meier method and compared using log-rank test. Multiregion single-nucleotide polymorphism array analysis was performed on 13 early-stage resected EGFR-mutant-positive NSCLC across 59 sectors to investigate intratumoral heterogeneity of MET CNG.

RESULTS

Fifty-two (26%) of 200 patients in the metastatic cohort were MET-high at diagnosis; 46 (23%) had polysomy and six (3%) had amplification. Median TTF was 12.2 months (95% CI, 5.7 to 22.6 months) versus 13.1 months (95% CI, 10.6 to 15.0 months) for MET-high and -low, respectively ( P = .566), with no significant difference in response rate regardless of copy number thresholds. Loss of MET was observed in three of six patients identified as MET-high who underwent postprogression biopsies, which is consistent with marked intratumoral heterogeneity in MET CNG observed in early-stage tumors. Suboptimal response (TTF, 1.0 to 6.4 months) to EGFR TKI was observed in patients with coexisting MET amplification (five [3.2%] of 154).

CONCLUSION

Although up to 26% of TKI-naïve EGFR-mutant-positive NSCLC harbor high MET CNG by fluorescence in situ hybridization, this did not significantly affect response to TKI, except in patients identified as MET-amplified. Our data underscore the limitations of adopting arbitrary copy number thresholds and the need for cross-assay validation to define therapeutically tractable MET pathway dysregulation in EGFR-mutant-positive NSCLC.

Elucidating the genomic architecture of Asian EGFR-mutant lung adenocarcinoma through multi-region exome sequencing

EGFR-mutant lung adenocarcinomas (LUAD) display diverse clinical trajectories and are characterized by rapid but short-lived responses to EGFR tyrosine kinase inhibitors (TKIs). Through sequencing of 79 spatially distinct regions from 16 early stage tumors, we show that despite low mutation burdens, EGFR-mutant Asian LUADs unexpectedly exhibit a complex genomic landscape with frequent and early whole-genome doubling, aneuploidy, and high clonal diversity. Multiple truncal alterations, including TP53 mutations and loss of CDKN2A and RB1, converge on cell cycle dysregulation, with late sector-specific high-amplitude amplifications and deletions that potentially beget drug resistant clones. We highlight the association between genomic architecture and clinical phenotypes, such as co-occurring truncal drivers and primary TKI resistance. Through comparative analysis with published smoking-related LUAD, we postulate that the high intra-tumor heterogeneity observed in Asian EGFR-mutant LUAD may be contributed by an early dominant driver, genomic instability, and low background mutation rates.

EGFR mutant lung adenocarcinoma (LUAD) exhibit diverse clinical outcomes in response to targeted therapies. Here the authors show that these LUADs involve a complex genomic landscape with high intratumor heterogeneity, providing insights into the evolutionary trajectory of oncogene-driven LUAD and potential mediators of EGFR TKI resistance.

Study on Neurological Consequence of Eclampsia

The present study was carried out in the Department of Obstetrics and Gynecology at Mymensingh Medical College Hospital, Mymensingh, Bangladesh for a period of one year from 1st June 2009 to 30th June 2010 to see the Neurological Consequence of Eclampsia. A total number of 37 patients were enrolled in this study. Among 37 patients majority are in the age group of 21-30 years which is 19(51.4%) cases followed by less than or equal to 20 years and more than 30 years which are 13(35.1%) cases and 5(13.5%) cases respectively. Knee jerk is present in 28(75.7%) cases and absent in 8(21.6%) cases. The exaggerated knee jerk is present in only in 1(2.7%) case. The rate of Glasgow coma scale is less than 5 in 21(56.8%) cases, 14(37.8%) cases in 5-10 and 2(5.4%) cases is in more than 10. Focal sign is absent in 22(59.5%) cases and present in 15(40.5%) cases. Majority of the patients is presented with absence of neck stiffness which is 35(94.6%) cases and the rest 2(5.4%) cases are presented with neck stiffness. Flexor planter response is found in 20(54.1%) cases which is the highest in number followed by extensor which is 15(40.5%) cases. In only 2(5.4%) cases the planter reflex is not elicitable. Presence of infarct is found in 15(40.5%) cases which is the highest number. Cerebral edema and Presence of haemorrhage is found in 3(8.1%) cases in each. Leuko-encephalopathy is found in 2(5.4%) cases. Encephalopathy and Both infarct & haemorrhage is found in 1(2.7%) case of each. Normal CT scan findings of brain are found in 12(32.4%) cases.

Abstract B2-54: Intratumor heterogeneity in never-smoker Asian EGFR mutant lung adenocarcinoma

Lung cancer has the highest cancer associated mortality rate in many countries across the world. In contrast to western populations, approximately half of lung adenocarcinoma cases in Singapore harbour activating epidermal growth factor receptor (EGFR) mutations, with preponderance for never smokers and female gender. Although EGFR tyrosine kinase inhibitors (TKIs) confer high response rates of up to 70%, drug resistance invariably ensues - most commonly through the “acquisition” of EGFR T790M mutation. While the extent and pattern of intratumoral heterogeneity (ITH) in non-small cell lung cancer (NSCLC) were recently described, these studies examined histologically and molecularly diverse cohort of patients, majority being current or ex-smokers. Here we report ITH in eight never-smoker EGFR mutant lung adenocarcinoma cases of Asian ethnicity.

All eight patients had no prior treatment history and harboured an activating EGFR mutation (5 L858R , 2 exon 19 deletion, 1 exon 20 insertion). They underwent lobectomy for Stage IA, IB NSCLC. Tumors were harvested using a systematic sectoring protocol according to standard operation procedures, with tissue banked for exome sequencing, RNA-sequencing and SNP array. A total of 46 tumor sectors (at least 4 regions from each of the 8 tumors) were subject to whole exome sequencing, with matched normal samples.

With an average sequencing depth of 100x, we identified 860 somatic exonic SNVs (601 being non-synonymous) and 49 indels across all samples. The median number of SNVs per patient was 112 and per sector was 49. Notably, activating EGFR mutations were identified across all tumor sectors of all but two patients (for whom it was identified in 3 of 5 and 5 of 7 sectors respectively). In addition, we did not identify the EGFR T790M mutation in any of the sequenced tumor sectors, suggesting that, this resistance mutation is not present at detectable frequencies even as a branch or subclonal event in a treatment naïve scenario. Of 20 genes that were significantly mutated across 46 individual tumor sectors, only two overlapped with published recurrently mutated genes in NSCLC.

In conclusion, we show that activating EGFR mutations are ubiquitous truncal events in 6 of 8 Asian never-smoker lung adenocarcinoma – consistent with its role as a therapeutically tractable driver gene. The T790M mutation commonly associated with TKI resistance was not detected as a subclonal event in treatment naïve patients. Further, our study reveals the unique mutation spectra of Asian EGFR mutant lung adenocarcinoma, highlighting the value of multi-region sequencing in characterising the genomic architecture of defined molecular subsets of NSCLC from different ethnic backgrounds.

Citation Format: Rahul Nahar, Weiwei Zhai, Angela Takano, Alexis Jiaying Khng, Xingliang Liu, Chong Hee Lim, Audrey S.M. Teo, Cheryl Xueli Chan, Apoorva Gogna, Kiat-Hon Lim, Tina Koh, Huay Mei Poh, Yin Yeng Lee, Liang He Chen, Tong Zhang, Vidhya Gomathi Krishnan, N Gopalakrishna Iyer, Pauline Ng, Wan Teck Lim, Bing Lim, Eng-Huat Tan, Daniel S.W. Tan, Axel M. Hillmer. Intratumor heterogeneity in never-smoker Asian EGFR mutant lung adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Computational and Systems Biology of Cancer; Feb 8-11 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 2):Abstract nr B2-54.

Abstract A1-25: Intratumor heterogeneity in never-smoker Asian EGFR mutant lung adenocarcinoma

Lung cancer has the highest cancer associated mortality rate in many countries across the world. In contrast to western populations, approximately half of lung adenocarcinoma cases in Singapore harbour activating epidermal growth factor receptor (EGFR) mutations, with preponderance for never smokers and female gender. Although EGFR tyrosine kinase inhibitors (TKIs) confer high response rates of up to 70%, drug resistance invariably ensues - most commonly through the “acquisition” of EGFR T790M mutation. While the extent and pattern of intratumoral heterogeneity (ITH) in non-small cell lung cancer (NSCLC) were recently described, these studies examined histologically and molecularly diverse cohort of patients, majority being current or ex-smokers. Here we report ITH in eight never-smoker EGFR mutant lung adenocarcinoma cases of Asian ethnicity.

All eight patients had no prior treatment history and harboured an activating EGFR mutation (5 L858R, 2 exon 19 deletion, 1 exon 20 insertion). They underwent lobectomy for Stage IA, IB NSCLC. Tumors were harvested using a systematic sectoring protocol according to standard operation procedures, with tissue banked for exome sequencing, RNA-sequencing and SNP array. A total of 46 tumor sectors (at least 4 regions from each of the 8 tumors) were subject to whole exome sequencing, with matched normal samples.

With an average sequencing depth of 100x, we identified 860 somatic exonic SNVs (601 being non-synonymous) and 49 indels across all samples. The median number of SNVs per patient was 112 and per sector was 49. Notably, activating EGFR mutations were identified across all tumor sectors of all but two patients (for whom it was identified in 3 of 5 and 5 of 7 sectors respectively). In addition, we did not identify the EGFR T790M mutation in any of the sequenced tumor sectors, suggesting that, this resistance mutation is not present at detectable frequencies even as a branch or subclonal event in a treatment naïve scenario. Of 20 genes that were significantly mutated across 46 individual tumor sectors, only two overlapped with published recurrently mutated genes in NSCLC.

In conclusion, we show that activating EGFR mutations are ubiquitous truncal events in 6 of 8 Asian never-smoker lung adenocarcinoma – consistent with its role as a therapeutically tractable driver gene. The T790M mutation commonly associated with TKI resistance was not detected as a subclonal event in treatment naïve patients. Further, our study reveals the unique mutation spectra of Asian EGFR mutant lung adenocarcinoma, highlighting the value of multi-region sequencing in characterising the genomic architecture of defined molecular subsets of NSCLC from different ethnic backgrounds.

Citation Format: Rahul Nahar, Weiwei Zhai, Angela Takano, Alexis Jiaying Khng, Xingliang Liu, Chong Hee Lim, Audrey S.M. Teo, Cheryl Xueli Chan, Apoorva Gogna, Kiat-Hon Lim, Tina Koh, Huay Mei Poh, Yin Yeng Lee, Liang He Chen, Tong Zhang, Vidhya Gomathi Krishnan, N Gopalakrishna Iyer, Pauline Ng, Wan Teck Lim, Bing Lim, Eng-Huat Tan, Daniel S.W. Tan, Axel M. Hillmer. Intratumor heterogeneity in never-smoker Asian EGFR mutant lung adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr A1-25.

Self-enforcing feedback activation between BCL6 and pre-B cell receptor signaling defines a distinct subtype of acute lymphoblastic leukemia

Studying 830 pre-B ALL cases from four clinical trials, we found that human ALL can be divided into two fundamentally distinct subtypes based on pre-BCR function. While absent in the majority of ALL cases, tonic pre-BCR signaling was found in 112 cases (13.5%). In these cases, tonic pre-BCR signaling induced activation of BCL6, which in turn increased pre-BCR signaling output at the transcriptional level. Interestingly, inhibition of pre-BCR-related tyrosine kinases reduced constitutive BCL6 expression and selectively killed patient-derived pre-BCR(+) ALL cells. These findings identify a genetically and phenotypically distinct subset of human ALL that critically depends on tonic pre-BCR signaling. In vivo treatment studies suggested that pre-BCR tyrosine kinase inhibitors are useful for the treatment of patients with pre-BCR(+) ALL.

Effectiveness of radioiodine therapy in treatment of hyperthyroidism

The present non randomized clinical trial was conducted in the Center for Nuclear Medicine and Ultrasound, Mymensingh, Bangladesh for duration of one year. Total 30 patients with hyperthyroidism diagnosed by clinical and biochemical profile were included in the study. All patients received radioiodine treatment and regular follow up at 1st month, 3rd month, 6th month & 9th month were done to evaluate clinical and biochemical status and complications. Data were analyzed by computer with SPSS programme using 't' test and chi-square test. In the present study, out of 30 respondents more than three fourth of the respondents (76.6%) were in the age group of 31-50 years followed by less than 30 years are group (16.7%) and rest of respondents were in the age group of more than 50 years (06.7%). Mean±SD and range of age of the respondents were 39.80±10.02 years and 17-65 years respectively. Among the 30 respondents 11(36.7%) were male and 19(63.3%) were female. Male to female ratio was 1:1.73. Out of 30 patients 26(86.7%) presented with goiter and among them 21(80.8%) has diffused goiter and five (19.2%) had nodular goiter. Baseline mean±SD, median, range of serum T₃ level were 5.24±3.62, 4.34, 1.48-14.65nmol/L respectively. Base line mean±SD, median range of serum T₄ level were 192.25±99.17, 201.77, 1.75-336.25nmol/L respectively. Baseline mean±SD, median range of serum TSH level were 6.33±23.93, 0.15-0.07, 130.46nmol/L respectively. In the present study serum T₃, T₄ level among the respondents sharply decrease from baseline to 2nd follow up then gradually decrease from 2nd to 4th follow up. Serum TSH level gradually increases from baseline to 3rd follow up and then gradually decreases from 3rd to 4th follow up. The result showed radioiodine is an effective option for the treatment of thyrotoxicosis.

Lifestyle related causes of cancer and chemoprevention through phytonutrients

Cancer is a leading cause of death worldwide. There are a lot of cancer causing agents which are divided as physical carcinogens, chemical carcinogens and biological carcinogens. But most of the carcinogens or causes of cancer are related to our lifestyle like diet, habit, occupation, radiation and some infection, etc. Chemoprevention is highly necessary to prevent cancer related preterm death. For this besides avoiding the causes of cancer we should concentrate ourselves on our diet. Because, numerous phytochemicals derived from edible plants have been reported to interfere with a specific stage of the carcinogenic process. Many mechanisms have been shown to account for the anticarcinogenic actions of dietary constituents and recently attention has been focused on intracellular-signalling cascades as common molecular targets for various chemopreventive phytochemicals. In this study, we tried to describe lifestyle related causes of cancer and the molecular basis of cancer prevention through the phytochemicals.

BCL6 is critical for the development of a diverse primary B cell repertoire

BCL6 protects germinal center (GC) B cells against DNA damage-induced apoptosis during somatic hypermutation and class-switch recombination. Although expression of BCL6 was not found in early IL-7-dependent B cell precursors, we report that IL-7Ralpha-Stat5 signaling negatively regulates BCL6. Upon productive VH-DJH gene rearrangement and expression of a mu heavy chain, however, activation of pre-B cell receptor signaling strongly induces BCL6 expression, whereas IL-7Ralpha-Stat5 signaling is attenuated. At the transition from IL-7-dependent to -independent stages of B cell development, BCL6 is activated, reaches expression levels resembling those in GC B cells, and protects pre-B cells from DNA damage-induced apoptosis during immunoglobulin (Ig) light chain gene recombination. In the absence of BCL6, DNA breaks during Ig light chain gene rearrangement lead to excessive up-regulation of Arf and p53. As a consequence, the pool of new bone marrow immature B cells is markedly reduced in size and clonal diversity. We conclude that negative regulation of Arf by BCL6 is required for pre-B cell self-renewal and the formation of a diverse polyclonal B cell repertoire.

Pre-B cell receptor signaling in acute lymphoblastic leukemia

B cell lineage ALL represents by far the most frequent malignancy in children and is also common in adults. Despite significant advances over the past four decades, cytotoxic treatment strategies have recently reached a plateau with cure rates at 80 percent for children and 55 percent for adults. Relapse after cytotoxic drug treatment, initial drug-resistance and dose-limiting toxicity are among the most frequent complications of current therapy approaches. For this reason, pathway-specific treatment strategies in addition to cytotoxic drug treatment seem promising to further improve therapy options for ALL patients. In a recent study on 111 cases of pre-B cell-derived human ALL, we found that ALL cells carrying a BCR-ABL1-gene rearrangement lack expression of a functional pre-B cell receptor in virtually all cases. In a proof-of-principle experiment, we studied pre-B cell receptor function during progressive leukemic transformation of pre-B cells in BCR-ABL1-transgenic mice: Interestingly, signaling from the pre-B cell receptor and the oncogenic BCR-ABL1 kinase are mutually exclusive and only "crippled" pre-B cells that fail to express a functional pre-B cell receptor are permissive to transformation by BCR-ABL1.

Pre-B cell receptor-mediated cell cycle arrest in Philadelphia chromosome-positive acute lymphoblastic leukemia requires IKAROS function

B cell lineage acute lymphoblastic leukemia (ALL) arises in virtually all cases from B cell precursors that are arrested at pre–B cell receptor–dependent stages. The Philadelphia chromosome–positive (Ph⁺) subtype of ALL accounts for 25–30% of cases of adult ALL, has the most unfavorable clinical outcome among all ALL subtypes and is defined by the oncogenic BCR-ABL1 kinase and deletions of the IKAROS gene in >80% of cases. Here, we demonstrate that the pre–B cell receptor functions as a tumor suppressor upstream of IKAROS through induction of cell cycle arrest in Ph⁺ ALL cells. Pre–B cell receptor–mediated cell cycle arrest in Ph⁺ ALL cells critically depends on IKAROS function, and is reversed by coexpression of the dominant-negative IKAROS splice variant IK6. IKAROS also promotes tumor suppression through cooperation with downstream molecules of the pre–B cell receptor signaling pathway, even if expression of the pre–B cell receptor itself is compromised. In this case, IKAROS redirects oncogenic BCR-ABL1 tyrosine kinase signaling from SRC kinase-activation to SLP65, which functions as a critical tumor suppressor downstream of the pre–B cell receptor. These findings provide a rationale for the surprisingly high frequency of IKAROS deletions in Ph⁺ ALL and identify IKAROS-mediated cell cycle exit as the endpoint of an emerging pathway of pre–B cell receptor–mediated tumor suppression.

Surgical treatment of transposition of great arteries with interrupted pulmonary artery: a rare association of embryopathies

The first case of TGA with VSD, ASD, and interrupted LPA and its successful surgical treatment is being reported along with a review of the relevant literature. The dominant presenting clinical features have been explained and an attempt has been made to explain the paucity of records in regard to this embryopathy. An arterial switch for TGA and a glutaraldehyde pretreated autologous pericardial roll for repair of interrupted LPA were carried out. Pre- and postoperative hemodynamics and angiography data are also presented.

Childhood immunization in the State of Qatar: Implications for improving coverage

In Qatar, there is evidence of underuse of the immunization services despite easy access to health care. We therefore undertook a prospective study to determine the vaccination status and, more importantly, the reasons for inadequate immunization of a group of 255 preschool children attending the outpatient care facilities in Doha. A questionnaire was used to obtain relevant information, including parent's educational background. Sixty-six percent of the children were fully immunized for their age group, 12% were partially immunized, and 12% were not immunized. Eighty-eight percent had received their first dose of DPT/OPV, but only 57% had received their first booster by 18 months of age; 76% had received three doses of DPT/OPV. The main reasons for nonimmunized status were misinformation and lack of awareness in parents about vaccination. Parental oversight, misinformation, and medical deferral were the main reasons for partial immunization. Parents of unimmunized children were often illiterate. In Qatar, establishment of an aggressive ongoing public education campaign, as well as strict implementation of the World Health Organization's Expanded Programme on Immunization's policy of screenign all children at every health care contact for the need for vaccination, should substantially increase immunization coverage. Implementation of a recall system for defaulters should also lead to improved immunization rates.