Underutilization and disparities in access to EGFR testing among Medicare patients with lung cancer from 2010 - 2013.

BACKGROUND: Tumor testing for mutations in the epidermal growth factor receptor (EGFR) gene is indicated for all newly diagnosed, metastatic lung cancer patients, who may be candidates for first-line treatment with an EGFR tyrosine kinase inhibitor. Few studies have analyzed population-level testing. METHODS: We identified clinical, demographic, and regional predictors of EGFR & KRAS testing among Medicare beneficiaries with a new diagnosis of lung cancer in 2011-2013 claims. The outcome variable was whether the patient underwent molecular, EGFR and KRAS testing. Independent variables included: patient demographics, Medicaid status, clinical characteristics, and region where the patient lived. We performed multivariate logistic regression to identify factors that predicted testing. RESULTS: From 2011 to 2013, there was a 19.7% increase in the rate of EGFR testing. Patient zip code had the greatest impact on odds to undergo testing; for example, patients who lived in the Boston, Massachusetts hospital referral region were the most likely to be tested (odds ratio (OR) of 4.94, with a 95% confidence interval (CI) of 1.67-14.62). Patient demographics also impacted odds to be tested. Asian/Pacific Islanders were most likely to be tested (OR 1.63, CI 1.53-1.79). Minorities and Medicaid patients were less likely to be tested. Medicaid recipients had an OR of 0.74 (CI 0.72-0.77). Hispanics and Blacks were also less likely to be tested (OR 0.97, CI 0.78-0.99 and 0.95, CI 0.92-0.99), respectively. Clinical procedures were also correlated with testing. Patients who underwent transcatheter biopsies were 2.54 times more likely to be tested (CI 2.49-2.60) than those who did not undergo this type of biopsy. CONCLUSIONS: Despite an overall increase in EGFR testing, there is widespread underutilization of guideline-recommended testing. We observed racial, income, and regional disparities in testing. Precision medicine has increased the complexity of cancer diagnosis and treatment. Targeted interventions and clinical decision support tools are needed to ensure that all patients are benefitting from advances in precision medicine. Without such interventions, precision medicine may exacerbate racial disparities in cancer care and health outcomes.

Improving risk stratification among veterans diagnosed with prostate cancer: impact of the 17-gene prostate score assay.

BACKGROUND: Active surveillance (AS) has been widely implemented within Veterans Affairs' medical centers (VAMCs) as a standard of care for low-risk prostate cancer (PCa). Patient characteristics such as age, race, and Agent Orange (AO) exposure may influence advisability of AS in veterans. The 17-gene assay may improve risk stratification and management selection. OBJECTIVES: To compare management strategies for PCa at 6 VAMCs before and after introduction of the Oncotype DX Genomic Prostate Score (GPS) assay. STUDY DESIGN: We reviewed records of patients diagnosed with PCa between 2013 and 2014 to identify management patterns in an untested cohort. From 2015 to 2016, these patients received GPS testing in a prospective study. Charts from 6 months post biopsy were reviewed for both cohorts to compare management received in the untested and tested cohorts. SUBJECTS: Men who just received their diagnosis and have National Comprehensive Cancer Network (NCCN) very low-, low-, and select cases of intermediate-risk PCa. RESULTS: Patient characteristics were generally similar in the untested and tested cohorts. AS utilization was 12% higher in the tested cohort compared with the untested cohort. In men younger than 60 years, utilization of AS in tested men was 33% higher than in untested men. AS in tested men was higher across all NCCN risk groups and races, particular in low-risk men (72% vs 90% for untested vs tested, respectively). Tested veterans exposed to AO received less AS than untested veterans. Tested nonexposed veterans received 19% more AS than untested veterans. Median GPS results did not significantly differ as a factor of race or AO exposure. CONCLUSIONS: Men who receive GPS testing are more likely to utilize AS within the year post diagnosis, regardless of age, race, and NCCN risk group. Median GPS was similar across racial groups and AO exposure groups, suggesting similar biology across these groups. The GPS assay may be a useful tool to refine risk assessment of PCa and increase rates of AS among clinically and biologically low-risk patients, which is in line with guideline-based care.

Clinical Impact of 21-Gene Recurrence Score Test Within the Veterans Health Administration: Utilization and Receipt of Guideline-Concordant Care.

INTRODUCTION: Ensuring guideline-concordant cancer care is a Department of Veterans Affairs (VA) priority, especially as the number of breast cancer patients at VA medical centers (VAMCs) grows. We assessed the utilization and clinical impact of the 21-gene Recurrence Score test, which predicts 10-year risk of breast cancer recurrence and the likelihood of chemotherapy benefit, on veterans newly diagnosed with breast cancer. PATIENTS AND METHODS: We conducted a retrospective cohort study using 2011-2012 VA Central Cancer Registry, chart review, and laboratory test data. Independent variables assessed included patient and site-of-care characteristics. The outcome of interest was whether newly diagnosed, eligible (node negative, hormone-receptor positive, human epidermal growth factor receptor 2 [HER2] negative) veterans underwent the 21-gene test. We performed descriptive statistics on all patients and multivariate logistic regression to determine associations. We correlated treatments received with test results. RESULTS: Among 328 eligible veterans, 82 (25%) had the 21-gene test; 100 eligible veterans (30%) sought care at a VAMC where no tests were ordered. Receiving care at a VAMC that had women's health services (odds ratio [OR], 1.84, 95% confidence interval [CI], 1.05-3.22) and having tumor characteristics meeting the National Comprehensive Cancer Network 2010 test criteria (OR, 3.06, 95% CI, 1.69-5.57) were positive predictors of testing; increasing age (OR, 0.93, 95% CI, 0.91-0.96 per year) and fee-based care (OR, 0.46, 95% CI, 0.26-0.82) were negative predictors. The majority of tested patients received guideline-concordant care. CONCLUSION: Site of care and tumor characteristics were important predictors of test uptake. Facilitating delivery of guideline-concordant cancer care requires improved laboratory informatics and clinical decision support.

Clinical decisions surrounding genomic and proteomic testing among United States veterans treated for lung cancer within the Veterans Health Administration.

BACKGROUND: Current clinical guidelines recommend epidermal growth factor receptor (EGFR) mutational testing in patients with metastatic non-small cell lung cancer (NSCLC) to predict the benefit of the tyrosine kinase inhibitor erlotinib as first-line treatment. Proteomic (VeriStrat) testing is recommended for patients with EGFR negative or unknown status when erlotinib is being considered. Departure from this clinical algorithm can increase costs and may result in worse outcomes. We examined EGFR and proteomic testing among patients with NSCLC within the Department of Veterans Affairs (VA). We explored adherence to guidelines and the impact of test results on treatment decisions and cost of care. METHODS: Proteomic and EGFR test results from 2013 to 2015 were merged with VA electronic health records and pharmacy data. Chart reviews were conducted. Cases were categorized based on the appropriateness of testing and treatment. RESULTS: Of the 69 patients with NSCLC who underwent proteomic testing, 33 (48%) were EGFR-negative and 36 (52%) did not have documented EGFR status. We analyzed 138 clinical decisions surrounding EGFR/proteomic testing and erlotinib treatment. Most decisions (105, or 76%) were concordant with clinical practice guidelines. However, for 24 (17%) decisions documentation of testing or justification of treatment was inadequate, and 9 (7%) decisions represented clear departures from guidelines. CONCLUSION: EGFR testing, the least expensive clinical intervention analyzed in this study, was significantly underutilized or undocumented. The records of more than half of the patients lacked information on EGFR status. Our analysis illustrated several clinical scenarios where the timing of proteomic testing and erlotinib diverged from the recommended algorithm, resulting in excessive costs of care with no documented improvements in health outcomes.

21-Gene recurrence score testing among Medicare beneficiaries with breast cancer in 2010-2013.

PURPOSE: We evaluated national patient-level utilization of the 21-gene recurrence score (21-gene RS) test among Medicare beneficiaries with breast cancer. We analyzed clinical, demographic, and regional factors that predict testing. METHODS: Using 2010-2013 Medicare claims, we conducted a retrospective study of breast cancer patients. The outcome variable was whether the patient underwent testing. Independent variables expected to predict testing were age, gender, race, Medicaid status, clinical characteristics, and hospital referral region (HRR). RESULTS: From 2010 to 2013, the number of test orders increased by 23.0%. Of the 256,818 patients identified in 2011-2012 claims, 25,352 (9.9%) underwent the 21-gene RS test. Estrogen receptor-positive status was the strongest positive predictor of testing (odds ratio (OR) 2.58, 95% confidence interval (CI) 2.48-2.69). White patients were more likely to be tested than minorities (OR 1.46, 95% CI 1.39-1.52). Secondary cancer was the strongest negative predictor. Medicaid recipients were less likely to be tested (OR 0.74, 95% CI 0.71-0.78). The likelihood of testing decreased with increasing age and comorbidities. CONCLUSIONS: Despite widespread implementation of the 21-gene RS test, minorities and Medicaid recipients had less access to testing. Many patients with serious comorbidities or advanced age were tested even though the risk algorithm may not have been applicable to them.Genet Med advance online publication 23 March 2017.

Utilization of genetic tests: analysis of gene-specific billing in Medicare claims data.

PURPOSE: We examined the utilization of precision medicine tests among Medicare beneficiaries through analysis of gene-specific tier 1 and 2 billing codes developed by the American Medical Association in 2012. METHODS: We conducted a retrospective cross-sectional study. The primary source of data was 2013 Medicare 100% fee-for-service claims. We identified claims billed for each laboratory test, the number of patients tested, expenditures, and the diagnostic codes indicated for testing. We analyzed variations in testing by patient demographics and region of the country. RESULTS: Pharmacogenetic tests were billed most frequently, accounting for 48% of the expenditures for new codes. The most common indications for testing were breast cancer, long-term use of medications, and disorders of lipid metabolism. There was underutilization of guideline-recommended tumor mutation tests (e.g., epidermal growth factor receptor) and substantial overutilization of a test discouraged by guidelines (methylenetetrahydrofolate reductase). Methodology-based tier 2 codes represented 15% of all claims billed with the new codes. The highest rate of testing per beneficiary was in Mississippi and the lowest rate was in Alaska. CONCLUSIONS: Gene-specific billing codes significantly improved our ability to conduct population-level research of precision medicine. Analysis of these data in conjunction with clinical records should be conducted to validate findings.Genet Med advance online publication 26 January 2017.

Epidermal Growth Factor Receptor Mutational Testing and Erlotinib Treatment Among Veterans Diagnosed With Lung Cancer in the United States Department of Veterans Affairs.

INTRODUCTION: We examined mutational testing of the epidermal growth factor gene (EGFR) and erlotinib treatment among veterans diagnosed with non-small-cell lung cancer in the United States Department of Veterans Affairs (VA). Our objectives were to identify the prevalence of clinically actionable EGFR mutations, to determine whether testing and treatment were guideline concordant, to evaluate the impact of testing and treatment on survival, and to estimate the rate of testing. PATIENTS AND METHODS: Test results were linked to electronic health records from VA Corporate Data Warehouse and the VA Central Cancer Registry. We analyzed patient demographic and clinical characteristics, prevalence of EGFR mutations, and timing of EGFR mutational testing and erlotinib treatment based on pharmacy records. Overall survival was assessed by Kaplan-Meier analysis. RESULTS: Among 973 patients tested at 70 VA medical centers between 2011 and 2013, 64 (7%) had sensitizing EGFR mutations, 694 (71%) were EGFR wild type, and 168 (17%) had clinically insignificant polymorphisms or variants of unknown significance. Results were not documented in 47 tests (5%). Erlotinib administration was in agreement with test results in 843 cases (87%). CONCLUSION: Veterans have a much lower rate of sensitizing EGFR mutations than the reported average of 10% to 15%, which correlates with a high rate of smoking among veterans. This may partially explain clinicians' reluctance to prescribe EGFR testing, which results in underutilization. Although test results appear to have influenced erlotinib treatment decisions, we documented a substantial number of cases where treatment was not applied in accordance with clinical guidelines, potentially resulting in worse outcomes and unnecessary cost.

BRCA testing within the Department of Veterans Affairs: concordance with clinical practice guidelines.

Guideline-concordant cancer care is a priority within the Department of Veterans Affairs (VA). In 2009, the VA expanded its capacity to treat breast cancer patients within VA medical centers (VAMCs). We sought to determine whether male and female Veterans diagnosed with breast cancer received BRCA testing as recommended by the National Comprehensive Cancer Network (NCCN) guidelines on Genetic/Familial High-Risk Assessment in Breast and Ovarian Cancer (v. 1.2010-1.2012). Using the 2011-2012 VA Central Cancer Registry and BRCA test orders from Myriad Genetics, we conducted a retrospective study. The outcome variable was a recommendation for genetic counseling or BRCA testing, determined by chart review. Independent variables expected to predict testing included region, site of care, and patient characteristics. We performed descriptive analysis of all patients and conducted multivariable logistic regression on patients who sought care at VAMCs that offered BRCA testing. Of the 462 Veterans who met NCCN testing criteria, 126 (27 %) received guideline-concordant care, either a referral for counseling or actual testing. No BRCA testing was recommended in 49 (50 %) VAMCs that provide cancer treatment. Surprisingly, patients with second primary breast cancer were less likely to be referred/tested (OR 0.39; CI 0.17, 0.89; p = 0.025). For patients under age 51, a yearly increase in age decreased likelihood of referral or testing (OR 0.85; CI 0.76, 0.94; p < 0.001). There were no differences in testing by race. In conclusion, there was significant underutilization and lack of access to BRCA testing for Veterans diagnosed with breast cancer. Our research suggests the need for clinical decision support tools to facilitate delivery of guideline-concordant cancer care and improve Veteran access to BRCA testing.

Implementation of Pharmacogenetic Testing Within the Veterans Health Administration From 2011 to 2013.

We assessed implementation of precision medicine within the Veterans Health Administration. We analyzed the use of interleukin-28B (IL28B) pharmacogenetic test, which predicts interferon-α treatment response in patients with hepatitis C. Patients with favorable CC genotype exhibit a two-fold higher response than patients with less favorable genotypes (CT and TT). Linking IL28B tests to Veterans Health Administration clinical data, we analyzed test use, concordance with guidelines, subsequent interferon-α treatment, and site variations. From January 2011 until December 2013, 3,529 Veterans underwent IL28B testing. There were 2,988 (85%) tests linked to electronic health record data. Demographics in those with clinical data: 97% male, mean age 59 years (SD 6.8), race: White 50%, Black 43%, Hispanic 3%, and other 3%. In Whites, the favorable CC genotype was three-fold more prevalent (541, 36%) than in Blacks (151, 12%). Analysis of IL28B timing revealed 2,373 (79%) Veterans were appropriately tested before interferon-α, 49 (2%) tested concurrent with interferon-α, and 566 (19%) tested post interferon-α treatment. Of the 630 treatment-naïve Veterans with CC genotype, only 144 (23%) initiated interferon-α treatment post-testing. Although 35% of IL28B tests overall did not influence care, the majority of tests were guideline concordant and clinically useful. IL28B testing varied substantially by site and state.

Implementation of the 21-gene recurrence score test in the United States in 2011.

PURPOSE: We examined hospital use of the 21-gene breast cancer test in the United States. We report state-level differences in utilization and propose a model for predicting implementation of guideline-recommended genomic testing. METHODS: Genomic Health provided test orders for calendar year 2011.We summarized utilization at the hospital and state levels. Using logistic regression, we analyzed the association between the likelihood to order the test and the hospital's institutional and regional characteristics. RESULTS: In 2011, 45% of 4,712 acute-care hospitals ordered the test, which suggests that 25% of newly diagnosed invasive female breast cancer cases were tested. Significant predictors of testing included participation in National Cancer Institute (NCI) clinical research cooperative groups (odds ratio (OR) 3.73; 95% confidence interval, 2.96-4.70), advanced imaging (OR, 2.19; CI, 1.78-2.68), high-complexity laboratory (OR, 2.15; CI, 1.24-3.70), affiliation with a medical school (OR, 1.57; CI, 1.31-1.88), and reconstructive surgery (OR, 1.23; CI, 1.01-1.50). Significant regional predictors included metropolitan county (OR, 3.77; CI, 2.83-5.03), above-mean income (OR, 1.37; CI, 1.11-1.69), and education (OR, 1.26; CI, 1.03-1.54). Negative predictors included designation as a critical-access hospital (OR, 0.10; CI, 0.07-0.14) and distance from an NCI cancer center (OR, 0.998; CI, 0.997-0.999), with a 15% decrease in likelihood for every 100 miles. CONCLUSION: Despite considerable market penetration of the test, there are significant regional and site-of-care differences in implementation, particularly in rural states.Genet Med 18 10, 982-990.

Caring for Patients With Prostate Cancer Who Are BRCA Positive.

Genomic testing may be a vital component in the medical management of patients with complex clinical phenotypes and cancer.

Molecular diagnostic testing in breast cancer.

OBJECTIVES: An overview of molecular tests used in the treatment of breast cancer, organized by stage and clinical condition. DATA SOURCES: Systematic review of scientific literature, guideline recommendations, and data published by test manufacturers. CONCLUSION: Several molecular tests that analyze expression of cancer-related genes have been validated in clinical trials and are recommended by clinical practice guidelines to inform diagnosis and treatment decisions for personalized interventions. IMPLICATIONS FOR NURSING PRACTICE: Molecular testing has become an important part of patient care for those with breast cancer. Oncology nurses must understand this methodology to prescribe tests, interpret the results, and provide guidance to patients.

Genetic tests to identify risk for breast cancer.

OBJECTIVES: To describe the currently available genetic tests that identify hereditary risk for breast cancer. DATA SOURCES: Systematic review of scientific literature, clinical practice guidelines, and data published by test manufacturers. CONCLUSION: Changes in gene patent laws and advances in sequencing technologies have resulted in rapid expansion of genetic testing. While BRCA1/2 are the most recognized genes linked to breast cancer, several laboratories now offer multi-gene panels to detect many risk-related mutations. IMPLICATIONS FOR NURSING PRACTICE: Genetic testing will be increasingly important in the prevention, diagnosis, and treatment of breast cancer. Oncology and advanced practice nurses must understand risk factors, significance of various genetic tests, and patient counseling.

Nerve growth factor regulates the expression of the cholinergic locus and the high-affinity choline transporter via the Akt/PKB signaling pathway.

Nerve growth factor (NGF) is a trophic and survival factor for cholinergic neurons, and it induces the expression of several genes that are essential for synthesis and storage of acetylcholine (ACh), specifically choline acetyltransferase, vesicular ACh transporter (VAChT), and choline transporter. We have found previously that the phosphatidylinositol 3'-kinase pathway, but not the MEK/MAPK pathway, is the mediator of NGF-induced cholinergic differentiation. Here we demonstrate, in the rat pheochromocytoma cell line PC12 and in primary mouse neuronal cultures, that NGF-evoked up-regulation of these three cholinergic-specific genes is mediated by the anti-apoptotic signaling molecule Akt/protein kinase B. Inhibition of Akt activation by the pharmacological inhibitor 1L-6-hydroxymethyl-chiro-inositol 2(R)-2-O-methyl-3-O-octadecylcarbonate (HIMO), or by a peptide fragment derived from the proto-oncogene TLC1, eliminated NGF-stimulated increases in cholinergic gene expression, as demonstrated by RT-PCR and reporter gene assays. Moreover, treatment with HIMO reversed NGF-evoked increases in choline acetyltransferase activity and ACh production. In co-transfection assays with the reporter construct, a dominant-negative Akt plasmid and Akt1-specific small interfering RNA also attenuated NGF-induced cholinergic promoter activity. Our data indicate that, in addition to its well-described role in promoting neuronal survival, Akt can also mediate signals necessary for neurochemical differentiation.

Differential regulation of the high affinity choline transporter and the cholinergic locus by cAMP signaling pathways.

Synthesis, storage and release of acetylcholine (ACh) require the expression of several specialized enzymes, including choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT) and the high-affinity choline transporter (CHT). Extracellular factors that regulate CHT expression and their signaling pathways remain poorly characterized. Using the NSC-19 cholinergic cell line, derived from embryonic spinal cord, we compared the effects of the second messenger cAMP on the expression of CHT and the cholinergic locus containing the ChAT and VAChT genes. Treatment of NSC-19 cells with dbcAMP and forskolin, thus increasing intracellular cAMP levels, significantly reduced CHT mRNA expression, while it upregulated ChAT/VAChT mRNA levels and ChAT activity. The cAMP-induced CHT downregulation was independent of PKA activity, as shown in treatments with the PKA inhibitor H-89. The alternative Epac-Rap pathway, when stimulated by a specific Epac activator, led to significant downregulation of CHT and ChAT, and, to a lesser extent, VAChT. In contrast, the PKA activator 6-BNZ-cAMP stimulated the expression of all three genes, but with varying concentration-dependence profiles. Our results indicate that elevations of intraneuronal cAMP concentration have differential effects on the cholinergic phenotype, depending on the involvement of different downstream effectors. Interestingly, although CHT is expressed predominantly in cholinergic cells, its regulation appears to be distinct from that of the cholinergic locus.

Developmental pattern of expression of BMP receptors and Smads and activation of Smad1 and Smad5 by BMP9 in mouse basal forebrain.

Basal forebrain cholinergic neurons play critical roles in the organization of brain cortical structures and in processes such as learning and memory. We have previously shown that bone morphogenetic protein (BMP) 9, a member of the transforming growth factor (TGF) beta superfamily of cytokines, is a differentiating factor for cholinergic central nervous system neurons. However, whereas the basic signal transduction pathways for most known members of the TGF-beta superfamily have been well characterized in brain and other organs, nothing is known about the signal transduction pathway of BMP9 in the brain. Here, we describe the pattern of expression of BMP receptors, including Bmpr-Ia, Bmpr-Ib, Bmpr-II, Actr-I. Actr-Ib, Actr-II and Actr-IIb, Alk-1, and Smad proteins (Smads 1-5 and Smad8) in the septal region of the basal forebrain during mouse development. Using cultured basal forebrain cells derived from embryonic day (E) 14 mice, we show that BMP9 causes phosphorylation of Smad1 and Smad5, formation of a complex of Smad4 with Samd1 and/or Smad5, and translocation of these proteins into the nucleus. These data show that BMP9 activates the canonical BMP signaling pathway and suggest that this could be one of the mechanisms responsible for the induction of the cholinergic phenotype by BMP9 in the basal forebrain.

Expression of high affinity choline transporter during mouse development in vivo and its upregulation by NGF and BMP-4 in vitro.

An important feature of cholinergic neurons is high-affinity choline transport, which allows them to reuse choline for the synthesis of ACh needed to support cholinergic neurotransmission. The choline transporter, designated CHT, was recently cloned. We applied RT/PCR to monitor the expression of CHT in the developing mouse CNS from embryonic day 14 (E14) to postnatal day 30 (P30). We found that CHT was expressed early in development, predominantly in the regions containing cholinergic neurons. In the spinal cord, CHT mRNA was present at close to adult levels at the earliest time point examined (E14) and showed almost no changes after birth. In the striatum and the septum, CHT mRNA increased steadily during embryonic stages and leveled off after birth. Surprisingly, CHT mRNA expression was also detected in other brain regions, notably in the cerebellum, where it peaked on E19, and then rapidly declined during postnatal development. CHT protein was detected by Western blotting as a band of apparent molecular weight of 70 kDa. The accumulation of this protein during development lagged behind mRNA accumulation in all tissues. We also examined the effects of NGF and BMP-4, the potent inducers of choline acetyltransferase and vesicular acetylcholine transporter genes, on CHT expression. Both factors increased CHT mRNA accumulation in primary septal cultures. The effect of NGF was dependent on the PI3K signaling, as it was abolished by the PI3K inhibitor LY294002. This result indicates that some of the signals regulating other cholinergic-specific genes also control CHT expression.

Bone morphogenetic protein 9 induces the transcriptome of basal forebrain cholinergic neurons.

Basal forebrain cholinergic neurons (BFCN) participate in processes of learning, memory, and attention. Little is known about the genes expressed by BFCN and the extracellular signals that control their expression. Previous studies showed that bone morphogenetic protein (BMP) 9 induces and maintains the cholinergic phenotype of embryonic BFCN. We measured gene expression patterns in septal cultures of embryonic day 14 mice and rats grown in the presence or absence of BMP9 by using species-specific microarrays and validated the RNA expression data of selected genes by immunoblot and immunocytochemistry analysis of their protein products. BMP9 enhanced the expression of multiple genes in a time-dependent and, in most cases, reversible manner. The set of BMP9-responsive genes was concordant between mouse and rat and included genes encoding cell-cycle/growth control proteins, transcription factors, signal transduction molecules, extracellular matrix, and adhesion molecules, enzymes, transporters, and chaperonins. BMP9 induced the p75 neurotrophin receptor (NGFR), a marker of BFCN, and Cntf and Serpinf1, two trophic factors for cholinergic neurons, suggesting that BMP9 creates a trophic environment for BFCN. To determine whether the genes induced by BMP9 in culture were constituents of the BFCN transcriptome, we purified BFCN from embryonic day 18 mouse septum by using fluorescence-activated cell sorting of NGFR(+) cells and profiled mRNA expression of these and NGFR(-) cells. Approximately 30% of genes induced by BMP9 in vitro were overexpressed in purified BFCN, indicating that they belong to the BFCN transcriptome in situ and suggesting that BMP signaling contributes to maturation of BFCN in vivo.