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4.
Circ Heart Fail ; 9(6)2016 06.
Article in English | MEDLINE | ID: mdl-27301467

ABSTRACT

BACKGROUND: Reducing hospital readmissions for patients with heart failure is a national priority, and quality improvement campaigns are targeting reductions of ≥20%. However, there are limited data on whether such targets have been met. METHODS AND RESULTS: We analyzed data from the American Heart Association's Get With The Guidelines-Heart Failure registry linked to Medicare claims between 2009 and 2012 to describe trends and relative reduction of rates of 30-day all-cause readmission among patients with heart failure. A total of 21,264 patients with heart failure were included from 70 US sites from January 2009 to October 2012. Overall hospital-level, risk-adjusted, 30-day all-cause readmission rates declined slightly, from 20.0% (SD, 1.3%) in 2009 to 19.0% (SD, 1.2%) in 2012 (P=0.001). Only 1 in 70 (1.4%) hospitals achieved the 20% relative reduction in 30-day risk-adjusted readmission rates. A multivariable linear regression model was used to determine hospital-level factors associated with relative improvements in 30-day risk-adjusted readmissions between 2009 and 2012. Teaching hospitals had higher relative readmission rates as compared with their peers, and hospitals that used postdischarge heart failure disease management programs had lower relative readmission rates. CONCLUSIONS: Although there has been slight improvement in 30-day all-cause readmission rates during the past 4 years in patients with heart failure, few hospitals have seen large success.


Subject(s)
Guideline Adherence/trends , Heart Failure/therapy , Patient Readmission/trends , Practice Guidelines as Topic , Practice Patterns, Physicians'/trends , Aged , Aged, 80 and over , Female , Heart Failure/diagnosis , Heart Failure/physiopathology , Hospitals, Teaching/trends , Humans , Linear Models , Male , Medicare/trends , Multivariate Analysis , Quality Improvement/trends , Quality Indicators, Health Care/trends , Registries , Risk Factors , Time Factors , United States
5.
Genes Chromosomes Cancer ; 53(1): 67-77, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24249259

ABSTRACT

WTX is a tumor suppressor gene expressed during embryonic development and inactivated in 20-30% of cases of Wilms tumor, the most common pediatric kidney cancer. WTX has been implicated in several cellular processes including Wnt signaling, WT1 transcription, NRF2 degradation, and p53 function. Given that WTX is widely expressed during embryonic development and has been recently shown to regulate mesenchymal precursor cells in several organs, we tested for the potential involvement of WTX in a panel of pediatric tumors and adult sarcomas. A total of 353 tumors were screened for WTX deletions by fluorescence in situ hybridization (FISH). Discrete somatic WTX deletions were identified in two cases, one hepatoblastoma and one embryonal rhabdomyosarcoma, and confirmed by array comparative genomic hybridization. Direct sequencing of the full WTX open reading frame in 24 hepatoblastomas and 21 embryonal rhabdomyosarcomas did not identify additional mutations in these tumor types. The presence of WTX mRNA was confirmed in hepatoblastomas and embryonal rhabdomyosarcomas without WTX deletions by RNA-in situ hybridization. Notably, tumors with evidence of WTX inactivation, Wilms tumor, hepatoblastoma and rhabdomyosarcoma, are primitive tumors that resemble undifferentiated precursor cells and are linked to overgrowth syndromes. These results indicate that WTX inactivation occurs in a wider variety of tumor types than previously appreciated and point to shared pathogenic mechanisms between a subset of pediatric malignancies.


Subject(s)
Adaptor Proteins, Signal Transducing/genetics , Hepatoblastoma/genetics , Liver Neoplasms/genetics , Rhabdomyosarcoma, Embryonal/genetics , Tumor Suppressor Proteins/genetics , Wilms Tumor/genetics , Adult , Child, Preschool , Female , Gene Expression Regulation , Humans , Male , Sequence Deletion
6.
Clin Cancer Res ; 19(2): 480-90, 2013 Jan 15.
Article in English | MEDLINE | ID: mdl-23186780

ABSTRACT

PURPOSE: Salivary duct carcinomas (SDC) are a rare and aggressive subtype of salivary gland cancers for which cytotoxic chemotherapy has limited efficacy. We investigated whether genotyping analysis could detect novel tumor-specific mutations that would help direct SDC patient treatment using targeted agents. EXPERIMENTAL DESIGN: We genotyped 27 SDC archival specimens from patients followed at Massachusetts General Hospital and Massachusetts Eye and Ear Infirmary (Boston, MA) between 2000 and 2011. These included the tumors of 8 patients who were tested prospectively. Targeted mutational analysis of 13 clinically relevant cancer genes was conducted using SNaPshot multiplexed genotyping. FISH was conducted to detect HER2 gene amplification. Patient medical records and tumor histopathologic features were retrospectively reviewed. RESULTS: Mutually exclusive genetic aberrations were detected in 15 of 27 (56%) tumors, including 2 (7%) mutations in BRAF, 5 (19%) mutations in PIK3CA, and 8 (30%) cases of HER2 gene amplification. To our knowledge, this is the first time that BRAF and PIK3CA mutations have been reported in this tumor type. Prospective clinical testing of 8 patients with SDC identified actionable genetic alterations in 6 tumors and influenced therapeutic decisions for all 6 patients. CONCLUSION: SNaPshot molecular profiling identified novel genetic changes in SDCs, expanded the therapeutic options for patients with this rare tumor, and is changing SDC management at our institution. These findings highlight the importance of using broad-based genetic profiling to expedite the identification of effective-targeted therapies for patients with rare malignancies.


Subject(s)
Carcinoma, Ductal/genetics , Salivary Gland Neoplasms/genetics , Adult , Aged , Aged, 80 and over , Antineoplastic Agents/therapeutic use , Carcinoma, Ductal/drug therapy , Carcinoma, Ductal/mortality , Carcinoma, Ductal/pathology , Class I Phosphatidylinositol 3-Kinases , Female , Gene Amplification , Gene Expression Profiling , Genotype , Humans , Male , Middle Aged , Mutation , Neoplasm Staging , Phosphatidylinositol 3-Kinases/genetics , Protein Kinase Inhibitors/therapeutic use , Proto-Oncogene Proteins B-raf/genetics , Receptor, ErbB-2/genetics , Salivary Gland Neoplasms/drug therapy , Salivary Gland Neoplasms/mortality , Salivary Gland Neoplasms/pathology , Young Adult
7.
Mod Pathol ; 25(11): 1462-72, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22743652

ABSTRACT

Chromosomal rearrangements leading to constitutive activation of anaplastic lymphoma receptor tyrosine kinase (ALK) define a category of lung adenocarcinomas that may be amenable to targeted therapy with the ALK inhibitor crizotinib. Defining distinctive features of ALK-rearranged (ALK+) lung adenocarcinomas may help identify cases that merit molecular testing. However, data describing the morphologic features of ALK+ lung adenocarcinomas are conflicting and are primarily based on analysis of resected primary lung tumors. It is unclear whether the findings from prior studies are applicable to metastatic lung tumors or to small biopsy/cytology specimens. To address these issues, we examined resection, excision, small biopsy, and cytology cell block specimens from 104 ALK+ and 215 ALK- lung adenocarcinomas from primary and metastatic sites. All cases were evaluated for ALK rearrangements by fluorescence in situ hybridization. The predominant histologic subtypes and distinctive cytomorphologic features were assessed in each case. Primary ALK+ lung adenocarcinomas showed a significant association with solid, micropapillary, and papillary-predominant histologic patterns and tumor cells with a signet ring or hepatoid cytomorphology. Among metastatic lung tumors and small biopsy/cytology specimens, the only distinguishing morphologic feature of ALK+ tumors was the presence of signet ring cells. Based on these results, we developed a morphology-based scoring system for predicting ALK rearrangements in lung adenocarcinomas. The scoring system predicted ALK rearrangements in a new cohort of 78 lung adenocarcinomas (29 ALK+ and 49 ALK-) with a sensitivity of 88% and a specificity of 45%. In conclusion, ALK+ lung adenocarcinomas have distinctive morphologic features, with signet ring cells showing a significant association with ALK rearrangements irrespective of tumor site (primary vs metastatic) or specimen type. However, morphologic screening alone will not detect a minority of ALK+ lung adenocarcinomas, and the routine use of ancillary studies may be warranted to identify all patients who may benefit from crizotinib treatment.


Subject(s)
Adenocarcinoma/genetics , Adenocarcinoma/secondary , Gene Rearrangement , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Receptor Protein-Tyrosine Kinases/genetics , Adenocarcinoma/drug therapy , Adenocarcinoma/enzymology , Adenocarcinoma of Lung , Adenocarcinoma, Papillary/enzymology , Adenocarcinoma, Papillary/genetics , Adenocarcinoma, Papillary/secondary , Adult , Aged , Aged, 80 and over , Anaplastic Lymphoma Kinase , Antineoplastic Agents/therapeutic use , Biopsy , Carcinoma, Signet Ring Cell/enzymology , Carcinoma, Signet Ring Cell/genetics , Carcinoma, Signet Ring Cell/secondary , Crizotinib , Female , Genetic Predisposition to Disease , Humans , In Situ Hybridization, Fluorescence , Logistic Models , Lung Neoplasms/drug therapy , Lung Neoplasms/enzymology , Male , Middle Aged , Multivariate Analysis , Patient Selection , Phenotype , Precision Medicine , Predictive Value of Tests , Prognosis , Protein Kinase Inhibitors/therapeutic use , Pyrazoles/therapeutic use , Pyridines/therapeutic use , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Young Adult
8.
Clin Cancer Res ; 18(5): 1227-36, 2012 Mar 01.
Article in English | MEDLINE | ID: mdl-22261808

ABSTRACT

PURPOSE: Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine tumor, often metastatic at presentation, for which current chemotherapeutic regimens are largely ineffective. As its pathogenesis is still unknown, we hypothesized that deregulation of signaling pathways commonly activated in cancer may contribute to MCC tumorigenesis and may provide insights into targeted therapy approaches for this malignancy. EXPERIMENTAL DESIGN: We retrospectively profiled 60 primary MCC samples using a SNaPshot-based tumor genotyping assay to screen for common mutations in 13 cancer genes. RESULTS: We identified mutations in 9 (15%) MCC primary tumors, including mutations in TP53 (3 of 60) and activating mutations in the PIK3CA gene (6 of 60). Sanger sequencing of the primary MCC tumors detected one additional PIK3CA mutation (R19K) that had not been previously described in cancer. Merkel cell polyoma virus (MCPyV) was detected in 38 (66%) MCC cases and patients with MCPyV-positive cancers showed a trend toward better survival. With one exception, the presence of MCPyV and activating mutations in PIK3CA appeared mutually exclusive. We observed that signaling through the PI3K/pAKT pathway was active in one MCPyV-positive and in all MCPyV-negative MCC cell lines, as evidenced by AKT phosphorylation. Importantly, the presence of a PIK3CA-activating mutation was associated with sensitivity to treatment with ZST474, a specific phosphoinositide 3-kinase (PI3K) inhibitor, and to NVP-BEZ235, a dual PI3K/mTOR inhibitor, targeted agents under active clinical development. CONCLUSIONS: PI3K pathway activation may drive tumorigenesis in a subset of MCC and screening these tumors for PIK3CA mutations could help identify patients who may respond to treatment with PI3K pathway inhibitors.


Subject(s)
Carcinoma, Merkel Cell/genetics , Phosphatidylinositol 3-Kinases/genetics , Signal Transduction , Skin Neoplasms/genetics , Adult , Aged , Aged, 80 and over , Base Sequence , Carcinoma, Merkel Cell/metabolism , Carcinoma, Merkel Cell/mortality , Cell Line, Tumor , Class I Phosphatidylinositol 3-Kinases , Enzyme Activation/drug effects , Enzyme Activation/genetics , Female , Genotype , Humans , Male , Middle Aged , Mutation , Neoplasm Staging , Phosphatidylinositol 3-Kinases/metabolism , Phosphoinositide-3 Kinase Inhibitors , Protein Kinase Inhibitors/pharmacology , Signal Transduction/drug effects , Signal Transduction/genetics , Skin Neoplasms/metabolism , Skin Neoplasms/mortality
9.
J Clin Oncol ; 30(8): 863-70, 2012 Mar 10.
Article in English | MEDLINE | ID: mdl-22215748

ABSTRACT

PURPOSE: Chromosomal rearrangements involving the ROS1 receptor tyrosine kinase gene have recently been described in a subset of non-small-cell lung cancers (NSCLCs). Because little is known about these tumors, we examined the clinical characteristics and treatment outcomes of patients with NSCLC with ROS1 rearrangement. PATIENTS AND METHODS: Using a ROS1 fluorescent in situ hybridization (FISH) assay, we screened 1,073 patients with NSCLC and correlated ROS1 rearrangement status with clinical characteristics, overall survival, and when available, ALK rearrangement status. In vitro studies assessed the responsiveness of cells with ROS1 rearrangement to the tyrosine kinase inhibitor crizotinib. The clinical response of one patient with ROS1-rearranged NSCLC to crizotinib was investigated as part of an expanded phase I cohort. RESULTS: Of 1,073 tumors screened, 18 (1.7%) were ROS1 rearranged by FISH, and 31 (2.9%) were ALK rearranged. Compared with the ROS1-negative group, patients with ROS1 rearrangements were significantly younger and more likely to be never-smokers (each P < .001). All of the ROS1-positive tumors were adenocarcinomas, with a tendency toward higher grade. ROS1-positive and -negative groups showed no difference in overall survival. The HCC78 ROS1-rearranged NSCLC cell line and 293 cells transfected with CD74-ROS1 showed evidence of sensitivity to crizotinib. The patient treated with crizotinib showed tumor shrinkage, with a near complete response. CONCLUSION: ROS1 rearrangement defines a molecular subset of NSCLC with distinct clinical characteristics that are similar to those observed in patients with ALK-rearranged NSCLC. Crizotinib shows in vitro activity and early evidence of clinical activity in ROS1-rearranged NSCLC.


Subject(s)
Carcinoma, Non-Small-Cell Lung/genetics , Gene Rearrangement , Lung Neoplasms/genetics , Protein-Tyrosine Kinases/genetics , Proto-Oncogene Proteins/genetics , Adenocarcinoma/genetics , Adult , Aged , Aged, 80 and over , Anaplastic Lymphoma Kinase , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/mortality , Crizotinib , Drug Screening Assays, Antitumor , Female , Humans , In Situ Hybridization, Fluorescence , Lung Neoplasms/drug therapy , Lung Neoplasms/mortality , Male , Middle Aged , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic use , Pyrazoles/pharmacology , Pyrazoles/therapeutic use , Pyridines/pharmacology , Pyridines/therapeutic use , Receptor Protein-Tyrosine Kinases/genetics , Retrospective Studies , Treatment Outcome
10.
J Clin Oncol ; 29(36): 4803-10, 2011 Dec 20.
Article in English | MEDLINE | ID: mdl-22042947

ABSTRACT

PURPOSE: Amplification of the MET proto-oncogene in gastroesophageal cancer (GEC) may constitute a molecular marker for targeted therapy. We examined a GEC cohort with follow-up and reported the clinical response of four additional patients with MET-amplified tumors to the small molecule inhibitor crizotinib as part of an expanded phase I cohort study. PATIENTS AND METHODS: From 2007 to 2009, patients with GEC were genetically screened as a consecutive series of 489 tumors (stages 0, I, and II, 39%; III, 25%; IV, 36%; n = 222 esophageal, including n = 21 squamous carcinomas). MET, EGFR, and HER2 amplification status was assessed by using fluorescence in situ hybridization. RESULTS: Ten (2%) of 489 patients screened harbored MET amplification; 23 (4.7%) harbored EGFR amplification; 45 (8.9%) harbored HER2 amplification; and 411 (84%) were wild type for all three genes (ie, negative). MET-amplified tumors were typically high-grade adenocarcinomas that presented at advanced stages (5%; n = 4 of 80). EGFR-amplified tumors showed the highest fraction of squamous cell carcinoma (17%; n = 4 of 23). HER2, MET, and EGFR amplification were, with one exception (MET and EGFR positive), mutually exclusive events. Survival analysis in patients with stages III and IV disease showed substantially shorter median survival in MET/EGFR-amplified groups, with a rank order for all groups by median survival (from most to least aggressive): MET (7.1 months; P < .001) less than EGFR (11.2 months; P = .16) less than HER2 (16.9 months; P = .89) when compared with the negative group (16.2 months). Two of four patients with MET-amplified tumors treated with crizotinib experienced tumor shrinkage (-30% and -16%) and experienced progression after 3.7 and 3.5 months. CONCLUSION: MET amplification defines a small and aggressive subset of GEC with indications of transient sensitivity to the targeted MET inhibitor crizotinib (PF-02341066).


Subject(s)
Adenocarcinoma/genetics , Esophageal Neoplasms/genetics , Gene Amplification , Protein Kinase Inhibitors/therapeutic use , Proto-Oncogene Proteins c-met/antagonists & inhibitors , Proto-Oncogene Proteins c-met/genetics , Pyrazoles/therapeutic use , Pyridines/therapeutic use , Stomach Neoplasms/genetics , Adenocarcinoma/drug therapy , Adenocarcinoma/pathology , Adult , Aged , Aged, 80 and over , Cohort Studies , Crizotinib , ErbB Receptors/genetics , Esophageal Neoplasms/drug therapy , Esophageal Neoplasms/pathology , Female , Genes, erbB-2 , Humans , Male , Middle Aged , Proto-Oncogene Mas , Stomach Neoplasms/drug therapy , Stomach Neoplasms/pathology
11.
J Thorac Oncol ; 6(5): 942-6, 2011 May.
Article in English | MEDLINE | ID: mdl-21623265
12.
Mod Pathol ; 24(9): 1177-90, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21572404

ABSTRACT

Adenocarcinoma of the distal esophagus and esophagogastric junction continues to rise in incidence. An intestinal metaplasia (Barrett esophagus)-dysplasia-carcinoma sequence induced by gastroesophageal reflux disease is well established. However, a significant number of adenocarcinomas in the vicinity of the esophagogastric junction are seen in the background of gastric/cardiac-type mucosa without intestinal metaplasia. Thus, the aim of this study was to investigate the role of Barrett esophagus (intestinal-type mucosa) in the classification and prognosis of tumors of the distal esophagus and esophagogastric junction. Clinicopathological and molecular characteristics were examined in 157 consecutively resected adenocarcinomas of the distal esophagus and esophagogastric junction and were compared between tumors arising in association with intestinal-type and cardiac-type mucosa. Intestinal-type mucosa-associated adenocarcinomas were more likely to be associated with younger age (P=0.0057), reflux symptoms (P<0.0001), proximal location (P=0.0009), lower T stage (P<0.0001), fewer nodal metastases (P=0.0001), absence of lymphatic (P<0.0001), venous (P=0.0060) or perineural (P<0.0001) invasion. Histologically, intestinal-type mucosa-associated tumors were more likely to be low-grade glandular tumors (P=0.0095) of intestinal or mixed immunophenotype (P=0.015) and express nuclear ß-catenin (P=0.0080), whereas tumors arising in a background of cardiac-type mucosa were more frequently associated with EGFR amplification (P=0.0051). Five-year overall survival rate was significantly higher in patients with intestinal-type mucosa-associated tumors (28 vs 9%, P=0.0015), although no survival benefit was seen after adjusting for potential confounders. Our findings support the theory that multiple distinct pathways of tumorigenesis exist in the vicinity of the esophagogastric junction, including one in which tumors arise from dysplastic intestinal metaplasia (intestinal pathway), and one potentially involving dysplasia of the cardiac-type mucosa (non-intestinal pathway). Additional studies are warranted to further clarify their pathogenesis and the molecular mechanisms involved.


Subject(s)
Adenocarcinoma/pathology , Barrett Esophagus/pathology , Esophageal Neoplasms/pathology , Esophagogastric Junction/pathology , Stomach Neoplasms/pathology , Adenocarcinoma/mortality , Adult , Aged , Aged, 80 and over , Barrett Esophagus/complications , Barrett Esophagus/mortality , Cardia/pathology , Esophageal Neoplasms/mortality , Female , Humans , Immunohistochemistry , Intestinal Mucosa/pathology , Kaplan-Meier Estimate , Male , Middle Aged , Precancerous Conditions/complications , Precancerous Conditions/mortality , Precancerous Conditions/pathology , Stomach Neoplasms/mortality , Tissue Array Analysis
13.
Sci Transl Med ; 3(75): 75ra26, 2011 Mar 23.
Article in English | MEDLINE | ID: mdl-21430269

ABSTRACT

Lung cancers harboring mutations in the epidermal growth factor receptor (EGFR) respond to EGFR tyrosine kinase inhibitors, but drug resistance invariably emerges. To elucidate mechanisms of acquired drug resistance, we performed systematic genetic and histological analyses of tumor biopsies from 37 patients with drug-resistant non-small cell lung cancers (NSCLCs) carrying EGFR mutations. All drug-resistant tumors retained their original activating EGFR mutations, and some acquired known mechanisms of resistance including the EGFR T790M mutation or MET gene amplification. Some resistant cancers showed unexpected genetic changes including EGFR amplification and mutations in the PIK3CA gene, whereas others underwent a pronounced epithelial-to-mesenchymal transition. Surprisingly, five resistant tumors (14%) transformed from NSCLC into small cell lung cancer (SCLC) and were sensitive to standard SCLC treatments. In three patients, serial biopsies revealed that genetic mechanisms of resistance were lost in the absence of the continued selective pressure of EGFR inhibitor treatment, and such cancers were sensitive to a second round of treatment with EGFR inhibitors. Collectively, these results deepen our understanding of resistance to EGFR inhibitors and underscore the importance of repeatedly assessing cancers throughout the course of the disease.


Subject(s)
Antineoplastic Agents/therapeutic use , Drug Resistance, Neoplasm/genetics , ErbB Receptors/antagonists & inhibitors , Genotype , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Protein Kinase Inhibitors/therapeutic use , Adult , Aged , Aged, 80 and over , Biopsy , ErbB Receptors/genetics , Erlotinib Hydrochloride , Female , Gefitinib , Humans , Male , Middle Aged , Mutation , Phenotype , Quinazolines/therapeutic use
14.
Mod Pathol ; 24(7): 974-82, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21423156

ABSTRACT

Metastasizing adnexal carcinomas are rare; thus, currently there is no uniform treatment guideline. Chemotherapeutic drugs that selectively target cancer-promoting pathways may complement conventional therapeutic approaches. We performed immunohistochemistry (epidermal growth factor receptor (EGFR), HER2, and CD117), EGFR and ERBB2 fluorescence in situ hybridization (FISH), and multiplexed SNaPshot® genotyping (testing for recurrent mutations in 15 cancer genes including BRAF, EGFR, KRAS, PIK3CA, and TP53) on primary tumors and corresponding metastases of 14 metastasizing adnexal carcinomas (three apocrine, six eccrine, two hidradenocarcinomas, two porocarcinomas, and one aggressive digital papillary adenocarcinoma). Metastasis to regional lymph node was most common, followed by skin and then lungs. Follow-up was available in 12 patients (5 months to 8 years) with 1 died of widespread metastases. Although EGFR overexpression was a prevalent feature in this cohort, seen in 7/11 (64%) primary tumors and 10/14 (71%) metastases; FISH for EGFR gene amplification was negative in 9 tested primary tumors and 12 metastases. FISH of the one primary tumor and three metastases with 2+ HER2 overexpression revealed a low level of ERBB2 gene amplification in one apocrine carcinoma and corresponding metastasis. CD117 expression was seen only in rare cases. PIK3CA (2/12, 17%) and TP53 (3/12, 25%) mutations were detected in two (one hidradenocarcinoma, one porocarcinoma) and three (one eccrine, one hidradenocarcinoma, and one aggressive digital papillary adenocarcinoma) cases, respectively. The role of EGFR inhibitor therapy in metastasizing adnexal carcinomas with protein overexpression remains unclear. Targeted therapy including PI3K pathway inhibitors might be a potential treatment for rare cases of adnexal carcinomas with metastases.


Subject(s)
Carcinoma/genetics , Carcinoma/metabolism , Neoplasm Metastasis/genetics , Sweat Gland Neoplasms/genetics , Sweat Gland Neoplasms/metabolism , Adult , Aged , Aged, 80 and over , Carcinoma/pathology , Class I Phosphatidylinositol 3-Kinases , DNA Mutational Analysis , Drug Delivery Systems , ErbB Receptors/analysis , ErbB Receptors/biosynthesis , ErbB Receptors/genetics , Female , Humans , Immunohistochemistry , Male , Middle Aged , Mutation , Neoplasm Metastasis/pathology , Phosphatidylinositol 3-Kinases/genetics , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins c-kit/analysis , Proto-Oncogene Proteins c-kit/biosynthesis , Proto-Oncogene Proteins c-kit/genetics , Proto-Oncogene Proteins p21(ras) , Receptor, ErbB-2/analysis , Receptor, ErbB-2/biosynthesis , Receptor, ErbB-2/genetics , Sweat Gland Neoplasms/pathology , Tumor Suppressor Protein p53/genetics , ras Proteins/genetics
15.
Sci Signal ; 3(149): ra84, 2010 Nov 23.
Article in English | MEDLINE | ID: mdl-21098728

ABSTRACT

Oncogenic BRAF mutations are found in several tumor types, including melanomas and colorectal cancers. Tumors with BRAF mutations have increased mitogen-activated protein kinase pathway activity and heightened sensitivity to BRAF and MEK (mitogen-activated or extracellular signal-regulated protein kinase kinase) inhibitors. To identify potential mechanisms of acquired drug resistance, we generated clones resistant to the allosteric MEK inhibitor AZD6244 from two BRAF V600E mutant colorectal cancer cell lines that are highly sensitive to MEK or BRAF inhibition. These AZD6244-resistant (AR) clones, which exhibited cross-resistance to BRAF inhibitors, acquired resistance through amplification of the BRAF gene. A small percentage of treatment-naïve parental cells showed preexisting BRAF amplification. We observed similar amplification in a subset of cells in a BRAF-mutant colorectal cancer. In cell lines, BRAF amplification increased the abundance of phosphorylated MEK and impaired the ability of AZD6244 to inhibit ERK (extracellular signal-regulated kinase) phosphorylation. The ability of AZD6244 to inhibit ERK phosphorylation in AR cells was restored by treatment with a BRAF inhibitor at low concentrations that reduced the abundance of phosphorylated MEK to amounts observed in parental cells. Combined MEK and BRAF inhibition fully overcame resistance to MEK or BRAF inhibitors alone and was also more effective in parental cells compared to treatment with either inhibitor alone. These findings implicate BRAF amplification as a mechanism of resistance to both MEK and BRAF inhibitors and suggest combined MEK and BRAF inhibition as a clinical strategy to overcome, or possibly prevent, this mechanism of resistance.


Subject(s)
Benzimidazoles/pharmacology , Drug Resistance, Neoplasm/genetics , Gene Amplification/genetics , Proto-Oncogene Proteins B-raf/genetics , Signal Transduction/drug effects , Analysis of Variance , Blotting, Western , Cell Line, Tumor , DNA Primers/genetics , Drug Resistance, Neoplasm/physiology , Humans , In Situ Hybridization, Fluorescence , Inhibitory Concentration 50 , Mitogen-Activated Protein Kinase Kinases/antagonists & inhibitors , Mitogen-Activated Protein Kinase Kinases/metabolism , Mutation, Missense/genetics , Phosphorylation/drug effects , Proto-Oncogene Proteins B-raf/antagonists & inhibitors , RNA, Small Interfering/genetics , Sequence Analysis, DNA
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