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Oncoproteins E6/E7 of the human papillomavirus types 16 & 18 synergize in modulating oncogenes and tumor suppressor proteins in colorectal cancer.

OBJECTIVE: Our study presents a novel analysis of the oncogenes and tumor suppressor proteins directly modulated by E6/E7 of high-risk HPV types 16 and 18, in colorectal cancer (CRC). METHODS: HCT 116 (KRAS mutant) & HT-29 (TP53 mutant) cell models of CRC were transduced with E6/E7 of HPV16 and HPV18, individually and in combination. Further, we utilized a liquid chromatography mass spectrometry (LC-MS/MS) approach to analyze and compare the proteomes of both CRC cell models. RESULTS: We generated six stably transduced cell lines. Our data revealed a significantly higher, HPV-induced modulation of oncogenes and tumor suppressor proteins in the TP53 mutant model, as compared to the KRAS mutant model (p ≤ 0.01). Less than 1% of the genes were commonly modulated by HPV, between both models. We also report that HT-29 cells, expressing E6/E7 of both HPV types, significantly reduced the suppression of oncogenes as compared to cells expressing E6/E7 of either HPV types individually (p-value ≤0.00001). CONCLUSION: Our data imply that HPV coinfections leads to the sustenance of a pro-oncogenic environment in CRC. HPV modulates different oncogenes/tumor suppressor proteins in CRC of varying mutational backgrounds, thus highlighting the importance of personalized therapies for such diseases with mutational heterogeneity.

Humans↗

Mutation analysis of 24 known cancer genes in the NCI-60 cell line set.

The panel of 60 human cancer cell lines (the NCI-60) assembled by the National Cancer Institute for anticancer drug discovery is a widely used resource. The NCI-60 has been characterized pharmacologically and at the molecular level more extensively than any other set of cell lines. However, no systematic mutation analysis of genes causally implicated in oncogenesis has been reported. This study reports the sequence analysis of 24 known cancer genes in the NCI-60 and an assessment of 4 of the 24 genes for homozygous deletions. One hundred thirty-seven oncogenic mutations were identified in 14 (APC, BRAF, CDKN2, CTNNB1, HRAS, KRAS, NRAS, SMAD4, PIK3CA, PTEN, RB1, STK11, TP53, and VHL) of the 24 genes. All lines have at least one mutation among the cancer genes examined, with most lines (73%) having more than one. Identification of those cancer genes mutated in the NCI-60, in combination with pharmacologic and molecular profiles of the cells, will allow for more informed interpretation of anticancer agent screening and will enhance the use of the NCI-60 cell lines for molecularly targeted screens.

Cell Line, Tumor↗

Clonal and parallel evolution of primary lung cancers and their metastases revealed by molecular dissection of cancer cells.

PURPOSE: Several models of cancer progression, including clonal evolution, parallel evolution, and same-gene models, have been proposed to date. The purpose of this study is to investigate the authenticity of these models by comparison of accumulated genetic alterations between primary and corresponding metastatic lung cancers. EXPERIMENTAL DESIGN: A whole-genome allelic imbalance scanning using a high-resolution single nucleotide polymorphism array and mutational analysis of the p53, EGFR, and KRAS genes were done on eight sets of primary and metastatic lung cancers. Based on the genotype data, the natural history of each case was deduced, and candidate metastasis suppressor loci were determined. RESULTS: Five to 20 chromosomal regions showed allelic imbalance in each tumor. Accumulated genetic alterations were similar between primary and corresponding metastatic tumors, and the majority(>67%) of genetic alterations detected in metastatic tumors was also detected in the corresponding primary tumors. On the other hand, in seven of the eight cases, there were genetic alterations accumulated only in metastatic tumors. Among these alterations, allelic imbalances at chromosome 11p15 and 11p11-p13 regions were the most frequent ones (4 of 8, 50%). Likewise, four cases showed genetic alterations detected only in primary tumors. CONCLUSIONS: The natural history of each case indicated that the process of metastasis varies among cases, and that all three models are applicable to lung cancer progression. According to the clonal and parallel evolution models, it is possible that a metastasis suppressor gene(s) for lung cancer is present on chromosome 11p.

Adult↗

Distributions of five common point mutants in the human tracheal-bronchial epithelium.

The mutations C742T, G746T, G747T in the TP53 gene and G35T in the KRAS gene have been repeatedly found in sectors of human tumors by direct DNA sequencing. The mutation G508A in the HPRT1 gene has been repeatedly found among peripheral T lymphocytes by clonal expansion under selective conditions. To discover if these mutations also occur frequently in normal tissues from which tumors arise, we have developed and validated allele-specific mismatch amplification mutation assays (MAMA) for each mutation. Reconstruction experiments demonstrated linearity in the range of 9-3000 mutant alleles among 3 x 10(6) wild-type alleles. The cumulative distributions of all negative controls established robust detection limits (P<0.05) of 34-125 mutants per 10(6) copies assayed depending on the mutation. One hundred and seventy-seven micro-anatomical samples of approximately (0.5-6)x10(6) tracheal-bronchial epithelial cells from nine non-smokers were assayed representing en toto the equivalent of approximately 1.6 human bronchial trees to the fifth bifurcation. Statistically significant mutant copy numbers were found in 257 of 463 assays. Clusters of mutant copies ranged from 10 to 1000 in 239/257 positive samples. As all five point mutations were detected at mutant fractions of >10(-5) in two or more lungs, we infer that they are mutational hotspots generated in lung epithelial stem cells. As the cancer-associated mutations did not differ in cluster size distribution from the HPRT1 mutation, we infer that none of the mutations conferred a growth advantage to somatic heterozygous clusters or maintenance turnover units. Specific mutants appeared in very large copy numbers, 1000-35,000, in 18/257 positive assays. Various hypotheses to account for the observed cluster size distributions are offered.

Adult↗

Loss of PBRM1 accelerates pancreatic cancer progression by inducing acquisition of mesenchymal phenotype and inflammatory cancer-associated fibroblasts reprogramming.

BACKGROUND: PBRM1 is an important subunit of the SWI/SNF complex, which broadly regulates gene transcription by chromatin remodeling. Genomic alterations of PBRM1 have been found in patients with pancreatic ductal adenocarcinoma (PDAC), but its molecular functions remain unclear. METHODS: Clinical relevance of PBRM1 was analyzed by using human PDAC samples and public genomic datasets. Mice with concomitant pancreas-specific Pbrm1 deletion in Kras-driven genetic PDAC models were generated. Single-cell transcriptomics were performed to determine tumor phenotype and microenvironment reprogramming. RESULTS: Reduction of PBRM1 expression was observed in human PDAC tissues and correlated with poor prognosis and metastasis. Pbrm1 loss promoted ductal metaplasia and delayed epithelial recovery in mice with caerulein-induced pancreatic injury. In PDAC model with either mutant Kras alone or in combination with Trp53 mutation, lack of Pbrm1 markedly accelerated tumor development and progression. Bulk transcriptomics and scRNA-seq identified reprogramming of both tumor compartment with mesenchymal phenotype acquisition and stroma compartment with inflammatory cancer-associated fibroblasts (iCAFs) transformation. Mechanistically, Pbrm1 deletion induced Zeb1 upregulation through epigenetic chromatin remodeling, thereby enhancing epithelial-mesenchymal and basal-like subtype transition. CONCLUSIONS: These findings indicated a tumor-suppressing role of PBRM1 in PDAC. PBRM1-deficient PDAC constitutes a specific subgroup of patients with aggressive phenotype and prognostic significance.

Animals↗

Ovarian Carcinoma Presenting Mucoepidermoid Carcinoma-Like Features in Association With Seromucinous Borderline Tumor: A Real Seromucinous Carcinoma?

Ovarian seromucinous carcinoma is generally classified within the spectrum of endometrioid carcinoma. We report a rare ovarian carcinoma with mucoepidermoid carcinoma-like features arising in direct association with a seromucinous borderline tumor. A 56-year-old postmenopausal female presented with a 10-cm pelvic multilocular cystic tumor and markedly elevated carbohydrate antigen 19-9. Histopathological examination showed a seromucinous borderline tumor with transition to invasive carcinoma composed of mucinous epithelial cells and p40-positive intermediate-like cells. The tumor was diffusely positive for PAX8 and negative for cytokeratin 20, supporting Mullerian differentiation. The p40-positive cell population persisted in the borderline, invasive, and para-aortic lymph node metastatic components. Comprehensive genomic profiling identified KRAS p.G12D without CTNNB1, PTEN, or ARID1A mutations. The patient developed platinum-resistant recurrence and died 11 months after diagnosis. This case is compatible with a potential endometriosis-independent pathway from seromucinous borderline tumor to an aggressive mucoepidermoid-like carcinoma.

mucoepidermoid carcinoma↗

Transformation of primate cells by chemicals and oncogenes: requirements for multiple factors.

Although several chemical carcinogenes have been shown to induce malignant transformation in human cells in culture, the molecular events involved in conversion of normal cells to malignant cells remain unknown at present. Normal human cells seem to be resistant to transformation by a single oncogene unless these cells have been immortalized by chemical carcinogens or DNA tumor virus genes. In some human cell systems, malignant phenotype is expressed after activation of protooncogenes probably through the mechanism of point mutations. Our results represent the first induction of KRAS gene rearrangement in cells of patients with familiar polyposis coli (FPC) treated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and 12-0-tetradecanoyl-phorbol-13-acetate (TPA). Whether or not KRAS rearrangement is a prerequisite for transformation in these cells is unknown. The contrast between the response of the FPC cells following treatment with these chemicals compared with that of normal fibroblasts suggests that KRAS gene rearrangement in FPC cells may be considered as a genetic marker for the disease. Studies of transformation with chemicals and oncogenes extended to nonhuman primate--marmoset cells have shown that two viral oncogenes, v-src and v-sis, converted marmoset cells to altered morphology, anchorage independence and immortality in cell culture. The transformed cells, however, lacked tumorigenicity in allogeneic and xenogeneic hosts. In v-src transformed cells additional changes associated with mutations of transforming virus and chromosome rearrangements were necessary for induction of tumorigenicity in allogeneic marmosets. Transformation of marmoset cells by chemical carcinogens depended on the type of target cells. Skin fibroblasts treated with MNNG acquired transformed morphology, anchorage independence and random chromosome aberrations. Kidney cells treated with the same carcinogen remained untransformed, but attained the same characteristics of transformation when exposed to TPA. Neither skin nor kidney transformed cells showed true tumorigenic potential in nude mice.

Adenomatous Polyposis Coli↗

Somatic mutations in the PTCH, SMOH, SUFUH and TP53 genes in sporadic basal cell carcinomas.

BACKGROUND: Basal cell carcinoma (BCC) of the skin is the most common human cancer. The genetic alterations underlying BCC development are only partly understood. OBJECTIVES: To investigate further the molecular genetics of sporadic BCCs, we performed mutation analyses of 10 skin cancer-associated genes in 42 tumours. METHODS: Single-strand conformational polymorphism analysis followed by DNA sequencing was used to screen for mutations in the sonic hedgehog pathway genes PTCH, SMOH, SUFUH and GLI1, in the TP53 tumour suppressor gene, and in the proto-oncogenes NRAS, KRAS, HRAS, BRAF and CTNNB1. Microsatellite markers flanking the PTCH, SUFUH and TP53 loci at 9q22, 10q24 and 17p13, respectively, were studied for loss of heterozygosity (LOH). RESULTS: PTCH mutations were found in 28 of 42 tumours (67%). Microsatellite analysis revealed LOH on 9q22 in 20 of 38 tumours investigated (53%), including 14 tumours with and six tumours without PTCH mutations. SMOH mutations were identified in four of the 42 BCCs (10%) while two tumours demonstrated mutations in SUFUH, including one missense mutation and one silent mutation. None of the BCCs showed LOH at markers flanking the SUFUH locus. Seventeen BCCs (40%) carried TP53 mutations, with only three tumours showing evidence of biallelic TP53 inactivation. TP53 mutations were present in BCCs with and without mutations in PTCH, SMOH or SUFUH. Interestingly, 72% of the TP53 alterations were presumably ultraviolet (UV)-induced transition mutations. In contrast, only 40% of the PTCH and SMOH alterations corresponded to UV signature mutations. No mutations were identified in GLI1, NRAS, KRAS, HRAS, BRAF or CTNNB1. CONCLUSIONS: Our data confirm the importance of PTCH, SMOH and TP53 mutations in the pathogenesis of sporadic BCCs. SUFUH alterations are restricted to individual cases while the other investigated genes do not appear to be important targets for mutations in BCCs.

Adult↗

Somatic activation of oncogenic Kras in hematopoietic cells initiates a rapidly fatal myeloproliferative disorder.

RAS mutations are common in myeloid malignancies; however, it is not known whether oncogenic RAS can initiate leukemia. We show that expressing mutant K-Ras(G12D) protein from the endogenous murine locus rapidly induces a fatal myeloproliferative disorder with 100% penetrance characterized by tissue infiltration, hypersensitivity to growth factors, and hyperproliferation. Hematopoietic cells from diseased mice demonstrated increased levels of Ras-GTP, but effector kinases were not constitutively phosphorylated and responded normally to growth factors. Oncogenic RAS is sufficient to initiate myeloid leukemogenesis in mice, and this provides an in vivo system for biologic and preclinical studies.

Animals↗

Whole-Genome Deep Learning Predicts Chemotherapy Response in Colorectal Cancer.

Chemotherapy response in colorectal cancer (CRC) exhibits significant heterogeneity, with current clinical predictors failing to capture complex genomic determinants of resistance. We developed a hybrid deep learning framework integrating convolutional neural networks (CNNs) and bidirectional long short-term memory (BiLSTM) networks to analyze whole-genome somatic mutations, evolutionary conservation, chromatin accessibility, and 3D genome architecture in 2,546 TCGA patients. An attention mechanism identified predictive genomic regions. The model achieved an AUC of 0.92 (95% CI: 0.89-0.94) in cross-validation and 0.88 (95% CI: 0.85-0.91) in independent validation, outperforming clinical models (&#x394;AUC = +0.18, p < 0.001). Key predictors included non-coding variants in TP53, KRAS, and PIK3CA regulatory regions. Triple-positive patients (mutations in all 3 regions) had significantly worse progression-free survival (HR = 4.7, p < 0.001). Our framework enables accurate chemotherapy response prediction and reveals novel non-coding resistance mechanisms, advancing precision oncology in CRC.

Humans↗

Smad4 is dispensable for normal pancreas development yet critical in progression and tumor biology of pancreas cancer.

SMAD4 is inactivated in the majority of pancreatic ductal adenocarcinomas (PDAC) with concurrent mutational inactivation of the INK4A/ARF tumor suppressor locus and activation of the KRAS oncogene. Here, using genetically engineered mice, we determined the impact of SMAD4 deficiency on the development of the pancreas and on the initiation and/or progression of PDAC-alone or in combination with PDAC--relevant mutations. Selective SMAD4 deletion in the pancreatic epithelium had no discernable impact on pancreatic development or physiology. However, when combined with the activated KRAS(G12D) allele, SMAD4 deficiency enabled rapid progression of KRAS(G12D)-initiated neoplasms. While KRAS(G12D) alone elicited premalignant pancreatic intraepithelial neoplasia (PanIN) that progressed slowly to carcinoma, the combination of KRAS(G12D) and SMAD4 deficiency resulted in the rapid development of tumors resembling intraductal papillary mucinous neoplasia (IPMN), a precursor to PDAC in humans. SMAD4 deficiency also accelerated PDAC development of KRAS(G12D) INK4A/ARF heterozygous mice and altered the tumor phenotype; while tumors with intact SMAD4 frequently exhibited epithelial-to-mesenchymal transition (EMT), PDAC null for SMAD4 retained a differentiated histopathology with increased expression of epithelial markers. SMAD4 status in PDAC cell lines was associated with differential responses to transforming growth factor-beta (TGF-beta) in vitro with a subset of SMAD4 wild-type lines showing prominent TGF-beta-induced proliferation and migration. These results provide genetic confirmation that SMAD4 is a PDAC tumor suppressor, functioning to block the progression of KRAS(G12D)-initiated neoplasms, whereas in a subset of advanced tumors, intact SMAD4 facilitates EMT and TGF-beta-dependent growth.

Alleles↗

Gene copy number for epidermal growth factor receptor (EGFR) and clinical response to antiEGFR treatment in colorectal cancer: a cohort study.

BACKGROUND: The antiepidermal growth factor receptor (antiEGFR) monoclonal antibodies cetuximab and panitumumab have good clinical activity in about 10% of patients with metastatic colorectal cancer that is resistant to chemotherapy. The molecular mechanisms underlying clinical response or resistance to these agents are unknown. METHODS: Tumours from 31 patients with metastatic colorectal cancer who had either an objective response (n=10) or stable disease or progressive disease (n=21) after treatment with cetuximab or panitumumab were screened for genetic changes in EGFR or its immediate intracellular effectors. Specifically, we assessed the EGFR copy number and the mutation profile of the EGFR catalytic domain and of selected exons in KRAS, BRAF, and PIK3CA. RESULTS: Eight of nine of patients with objective responses who were assessable by fluorescence in-situ hybridisation (FISH) had an increased EGFR copy number. By contrast, one of 21 non-responders assessable by FISH had an increased EGFR copy number (p<0.0001 for responders vs non-responders, Fisher's exact test). The mutation status of the EGFR catalytic domain and its immediate downstream effectors PIK3CA, KRAS, and BRAF did not correlate with disease response. In colorectal-cancer cell lines, the concentration of cetuximab that completely inhibited proliferation of cells with amplified EGFR copy number did not affect proliferation of cells with unamplified EGFR. INTERPRETATION: We propose that the response to antiEGFR treatment has a genetic basis and suggest that patients might be selected for treatment on the basis of EGFR copy number.

Aged↗

Genomic Characterization of ETV6::RUNX1-Positive Childhood B-ALL in a Chinese Cohort: Novel Fusion Partners, Co-Occurring Mutations, and Risk-Stratifying Biomarkers.

BACKGROUND: ETV6::RUNX1 is the most common genetic abnormality in pediatric B-cell acute lymphoblastic leukemia (ALL; &#x223c;25%), yet the comprehensive genetic architecture and molecular predictors of intermediate-risk (IR) stratification remain incompletely characterized. METHODS: We performed whole-transcriptome sequencing (Illumina NovaSeq 6000, rRNA depletion, 41.70 Gb/sample) on bone marrow samples from 93 pediatric ETV6::RUNX1-positive B-ALL patients. Bioinformatics analysis included STAR alignment, MuTect2 variant calling, FusionCatcher fusion detection, and VEP annotation. The Jaccard index with permutation testing assessed mutation co-occurrence; logistic regression identified independent predictors of IR classification. RESULTS: Beyond ETV6::RUNX1, we identified 51 distinct fusion genes across the cohort, including the reciprocal RUNX1-ETV6 (73.1%), chr8::KLF1210 (38.7%), and KLF12-chr8 (34.4%). Somatic mutations in 249 genes were detected; the most frequent were KIAA1715 (17.2%), KRAS (11.8%), and NSD2 (10.8%). Network analysis revealed significant chromatin modifier co-occurrence (KIAA1715-KMT2C: J = 0.136, p = 0.015) and KRAS-NRAS mutual exclusivity (J = 0.000, p = 0.042). PTCH1 (OR = 3.50, 95% CI 0.21-58.49, p = 0.41) and GNB1 (OR = 6.5, 95% CI 1.2-34.8, p = 0.029) mutations independently predicted IR classification. chr8::KLF1210 fusion correlated with higher Day-19 MRD levels (p = 0.038). CONCLUSIONS: GNB1 mutation represents a novel independent predictor of IR stratification in ETV6::RUNX1-positive B-ALL. The chromatin modifier co-occurrence module and extensive fusion architecture reveal biological heterogeneity within this favorable-risk subtype, with potential implications for risk-adapted therapeutic strategies.

B&#x2010;ALL↗

RAS mutations and clonality analysis in children with juvenile myelomonocytic leukemia (JMML).

Juvenile myelomonocytic leukemia (JMML) is a malignant hematopoietic disorder of early childhood with excessive proliferation of the myeloid and monocytic lineage. Deregulation of the RAS signal transduction pathway is thought to play a key role in its pathogenesis. We examined peripheral blood or bone marrow cells of 36 children with JMML for activating point mutations in codons 12, 13 and 61 of the NRAS and KRAS proto-oncogenes by allele-specific restriction assay, single-strand conformation polymorphism and/or direct sequencing. Codons 12, 13 and 61 of HRAS were examined in 26 of these patients. We detected RAS mutations in six cases (17%) located at N12 (n = 2), N13 (n = 3) and K13 (n = 1). In addition, we performed clonality studies on different cell lineages in four of these patients applying the RAS mutation, the karyotype and X-chromosome inactivation patterns as clonal markers. Erythroid cells carried mutant RAS, indicating clonal origin. In EBV B cell lines, one of three patients studied harbored a RAS mutation, while the other two patients had polyclonal B cells with wild-type RAS. T lymphocytes were examined in one patient; they were polyclonal and had wild-type RAS. It is likely that JMML is a heterogeneous disease with respect to clonal involvement of different lineages.

Amino Acid Substitution↗

Preinvasive and invasive ductal pancreatic cancer and its early detection in the mouse.

To evaluate the role of oncogenic RAS mutations in pancreatic tumorigenesis, we directed endogenous expression of KRAS(G12D) to progenitor cells of the mouse pancreas. We find that physiological levels of Kras(G12D) induce ductal lesions that recapitulate the full spectrum of human pancreatic intraepithelial neoplasias (PanINs), putative precursors to invasive pancreatic cancer. The PanINs are highly proliferative, show evidence of histological progression, and activate signaling pathways normally quiescent in ductal epithelium, suggesting potential therapeutic and chemopreventive targets for the cognate human condition. At low frequency, these lesions also progress spontaneously to invasive and metastatic adenocarcinomas, establishing PanINs as definitive precursors to the invasive disease. Finally, mice with PanINs have an identifiable serum proteomic signature, suggesting a means of detecting the preinvasive state in patients.

Animals↗

Establishment and characterization of four malignant pleural mesothelioma cell lines from Japanese patients.

Malignant pleural mesothelioma (MPM) is an asbestos-related malignancy that is highly resistant to current therapeutic modalities. We established four MPM cell lines (ACC-MESO-1, ACC-MESO-4, Y-MESO-8A and Y-MESO-8D) from Japanese patients, with the latter two from the same patient with biphasic-like characteristics of MPM, showing epithelial and sarcomatous phenotypes, respectively, in cell culture. These cells grew well in RPMI-1640 medium supplemented with 10% fetal bovine serum under 5% CO2. Mutation and expression analyses demonstrated that the tumor suppressor gene NF2, which is known to be one of the most frequently mutated in MPM, is mutated in ACC-MESO-1. We detected homozygous deletion of p16INK4A/p14ARF in all four MPM cell lines. However, mutations of other tumor suppressor genes, including TP53, and protooncogenes, including KRAS, NRAS, BRAF, EGFR and HER2, were not found in these cell lines. Polymerase chain reaction amplification of the simian virus 40 sequence did not detect any products. We also analyzed genetic alterations of six other MPM cell lines and confirmed frequent mutations of NF2 and p16INK4A/p14ARF. To characterize the biological differences between Y-MESO-8A and Y-MESO-8D, we carried out cDNA microarray analysis and detected genes that were differentially expressed in these two cell lines. Thus, our new MPM cell lines seem to be useful as new models for studying various aspects of the biology of human MPM as well as materials for the development of future therapies.

Adenocarcinoma↗

Comprehensive molecular profiling of advanced NSCLC in Greek patients:A prospective HeCOG study.

BACKGROUND: We report for the first time the molecular landscape and outcome associations from the prospective CLIMEDIN trial in Greece. METHODS: Two hundred patients with newly diagnosed advanced NSCLC (March 2022-October 2023) were enrolled and randomized to standard-of-care education versus additional automated, adverse-event-targeted digital interventions. Within this study baseline testing (EGFR, ALK, PD-L1) was performed in all; 165 tumors underwent comprehensive NGS (Oncomine Comprehensive Assay v3). Primary endpoint was improvement in AEs/QoL; secondary endpoints included ORR, PFS and OS. Associations between genomic alterations and outcomes were explored. RESULTS: Median age was 68 years; 75% male; 52% current smokers; adenocarcinoma 68.5%. Most received chemo-immunotherapy (66%). At data cut-off (December 2025; reverse-Kaplan-Meier median follow-up 36.3 months), median PFS was 9.6 months and median OS was 15.2 months. Across 200 tumors, 495 pathogenic variants (PVs) were identified in 83 genes. Exploratory outcome analyses showed longer OS in EGFR-mutant disease (preserved under parsimonious multivariable adjustment) and a formal KRAS &#xd7; smoking interaction for OS (interaction P = 0.011). CONCLUSIONS: In this cohort, the molecular profile mirrors other Caucasian series, with clinically relevant enrichment patterns for EGFR and KRAS. ECOG performance status and first line treatment were the dominant prognostic factors in this cohort. A novel KRAS and smoking interaction for overall survival warrants prospective validation.

Aged↗

Activated Kras and Ink4a/Arf deficiency cooperate to produce metastatic pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma ranks among the most lethal of human malignancies. Here, we assess the cooperative interactions of two signature mutations in mice engineered to sustain pancreas-specific Cre-mediated activation of a mutant Kras allele (KrasG12D) and deletion of a conditional Ink4a/Arf tumor suppressor allele. The phenotypic impact of KrasG12D alone was limited primarily to the development of focal premalignant ductal lesions, termed pancreatic intraepithelial neoplasias (PanINs), whereas the sole inactivation of Ink4a/Arf failed to produce any neoplastic lesions in the pancreas. In combination, KrasG12D expression and Ink4a/Arf deficiency resulted in an earlier appearance of PanIN lesions and these neoplasms progressed rapidly to highly invasive and metastatic cancers, resulting in death in all cases by 11 weeks. The evolution of these tumors bears striking resemblance to the human disease, possessing a proliferative stromal component and ductal lesions with a propensity to advance to a poorly differentiated state. These findings in the mouse provide experimental support for the widely accepted model of human pancreatic adenocarcinoma in which activated KRAS serves to initiate PanIN lesions, and the INK4A/ARF tumor suppressors function to constrain the malignant conversion of these PanIN lesions into lethal ductal adenocarcinoma. This faithful mouse model may permit the systematic analysis of genetic lesions implicated in the human disease and serve as a platform for the identification of early disease markers and for the efficient testing of novel therapies.

Animals↗