The prognostic value of KRAS mutation in locally advanced rectal cancer.

BACKGROUND: The prognostic value of the KRAS proto-oncogene mutation in colorectal cancer has been debated. Herein, we analyzed the National Cancer Database (NCDB) to assess the role of KRAS mutation as a prognostic marker in patients with locally advanced rectal cancer (LARC). METHODS: We identified LARC patients treated with neoadjuvant chemoradiation from 2004-2015 excluding those with stage I/IV disease and unknown KRAS status. Multivariable logistic regression identified variables associated with KRAS positivity. Propensity adjusted univariable and multivariable analyses identified predictors of survival. RESULTS: Of the 784 eligible patients, 506 were KRAS-negative (KRAS -) and 278 were KRAS-positive (KRAS +). Median survival was 63.6 months and 76.3 months for KRAS + and KRAS - patients respectively, with propensity adjusted 3 and 5-year survival of 79.9% vs. 83.6% and 56.7% vs. 61.9% respectively (HR 1.56, p 1.074-2.272). Male sex, no insurance, and KRAS + disease were associated with poorer survival on unadjusted and propensity adjusted multivariable analyses. CONCLUSIONS: Our analysis of KRAS + LARC suggest that KRAS + disease is associated with poorer overall survival. Given the inherent limitations of retrospective data, prospective validation is warranted.

Immunotherapy in gastroesophageal cancers: Current state and future directions.

While gastroesophageal (GE) cancers are one of the most common cancers worldwide, unfortunately, the mortality remains high. Commonly used treatment options include surgical resection, chemotherapy, radiotherapy, and molecular targeted therapy, which improve survival only minimally; thus, affirming the dire need for exploring alternative strategies to improve patient outcomes. Immunotherapy, which has revolutionized the world of oncology, has somewhat lagged behind in GE malignancies. Tumor-associated microenvironment and regulatory T cells, alongside cell cycle checkpoints, have been proposed by various studies as the mediators of carcinogenesis in GE cancers. Thus, inhibition of each of these could serve as a possible target of treatment. While the approval of pembrolizumab has provided some hope, it is not enough to override the dismal prognosis that this disease confers. Herein, we discuss the prospects of immunotherapy in this variety of cancer.

Definitive Chemoradiation for Rectal Cancer: Is There a Role for Dose Escalation? A National Cancer Database Study.

BACKGROUND: Surgery remains the standard of care in rectal cancer. Select patients will not undergo surgery for reasons such as medical inoperability or a watch-and-wait approach and instead are managed with definitive chemoradiation. OBJECTIVE: We used the National Cancer Database to identify overall survival and predictors thereof in the nonoperative management of patients with rectal cancer. DESIGN: This was a retrospective review. SETTINGS: This study used deidentified data from the National Cancer Database. PATIENTS: We queried the national cancer database from 2004 to 2014 for stage 1 to 3 rectal adenocarcinoma treated with only chemotherapy and radiation to definitive doses. Dose escalated therapy was defined as >54 Gy. MAIN OUTCOME MEASURES: Univariable and multivariable analyses were performed to identify sociodemographic, treatment, and tumor characteristics predictive of dose escalation and overall survival. Propensity-adjusted Cox proportional hazard ratios for survival were used to account for indication bias. RESULTS: Among the 6311 patients eligible for the study, 11% were treated with doses >54 Gy. Earlier stage and increased age/comorbidity patients were more likely to receive dose escalation, and patients with more recent treatment and treatment at an academic facility were less likely. The median follow-up time was 31 months (range, 2-154 mo). Three- and 5-year overall survival rates for all patients were 60% and 46%. Patients treated with dose escalation had a median survival of 33 months compared with 56 months for those treated with ≤54 Gy (p < 0.0001). LIMITATIONS: The main limitation is the inherent selection bias present in National Cancer Database studies. Important treatment details and outcomes as they relate to a definitive chemoradiation approach in rectal cancer are lacking. Salvage therapy was also not recorded, which in this population could be surgery. CONCLUSIONS: In this analysis, dose escalation in the nonoperative management of rectal cancer was associated with a lower overall survival compared with more conventional doses. Careful patient selection and enrollment on appropriate clinical trials may be warranted in the nonoperative setting. See Video Abstract at http://links.lww.com/DCR/B15. LA QUIMIORRADIACIÓN DEFINITIVA PARA EL CÁNCER RECTAL: ¿HAY LUGAR PARA EL AUMENTO DE LA DOSIS? UN ESTUDIO DE BASE DE DATOS NACIONAL DEL CÁNCER:: La cirugía sigue siendo el estándar en el tratamiento del cáncer rectal. Algunos pacientes no son quirúrgicos por razones como, no ser operables o con el enfoque de ver y esperar, y en su lugar son tratados con la quimiorradiación definitiva.Utilizamos la base de datos nacional del cáncer para identificar la supervivencia general y los factores predictivos de la misma, en el tratamiento no quirúrgico de pacientes con cáncer rectal.Esta fue una revisión retrospectiva.Utilizamos los datos identificados en la base de datos nacional del cáncer.Se consultó la base de datos nacional del cáncer del 2004-2014, para adenocarcinoma rectal en estadio 1-3, tratada únicamente con quimioterapia y radiación hasta la dosis definitiva. La terapia de aumento de la dosis se definió como >54 Gy.Se realizaron análisis univariables y multivariables para identificar características sociodemográficas, de tratamiento y predictivas del aumento de la dosis y supervivencia en general. Los índices de riesgo proporcionales de Cox ajustados a la propensión para la supervivencia, se utilizaron para tener en cuenta el sesgo de indicación.Entre los 6311 pacientes elegibles para el estudio, el 11% fue tratado con dosis >54 Gy. Los pacientes en estadios tempranos y con mayor edad/comorbilidad, tenían más probabilidades de recibir aumento de la dosis, y menos propensos los pacientes con tratamientos recientes y de centros académicos. El tiempo medio de seguimiento fue de 31 meses (2-154 meses). Las tasas de supervivencia global de tres y cinco años para todos los pacientes, fueron respectivamente del 60% y 46%. Los pacientes tratados con aumento de la dosis, tuvieron una supervivencia media de 33 meses, en comparación con los 56 meses para los pacientes tratados con ≤54 Gy (p < 0,0001).La principal limitación es el inherente sesgo en la selección, presente en los estudios de la base de datos nacional del cáncer. Faltan los detalles importantes del tratamiento y los resultados en relación con el enfoque definitivo de quimiorradiación en cáncer rectal. Tampoco se registró la terapia de rescate, que en esta población podría ser la cirugía.En este análisis, el aumento de la dosis en el manejo no quirúrgico del cáncer rectal, se asoció con una menor supervivencia global, en comparación con la dosis más convencional. La cuidadosa selección del paciente y la inscripción en los apropiados ensayos clínicos, pueden estar justificados en el entorno no quirúrgico. Vea el Resumen del Video en http://links.lww.com/DCR/B15.

Niraparib - A promising drug with hematological toxicity.

Ovarian cancer is the second most common and the most lethal gynecological malignancy in the western world. Unfortunately, there are lack of methods for early screening and diagnosis of the disease. Because of this, most of the cases are diagnosed at an advanced stage and have poor prognosis. The standard treatment of ovarian cancer is maximal cytoreductive surgical debulking followed by platinum-based chemotherapy. There are new molecular agents available for maintenance therapy of ovarian cancer including anti-angiogenic therapies, poly adenosine diphosphate ribose polymerase inhibitors, inhibitors of growth factor signaling, or folate receptor inhibitors, as well as several immunotherapeutic approaches. Niraparib is a poly adenosine diphosphate ribose polymerase inhibitor that has shown to be clinically effective as maintenance therapy in patients with platinum sensitive, recurrent ovarian cancer. Studies have shown the median duration of progression-free survival was significantly longer among those receiving niraparib than among those receiving placebo, regardless of presence or absence of BRCA gene mutations or homologous recombination deficiency status. Studies have shown that treatment-emergent Grade 3 or Grade 4 hematological events were observed in patients receiving niraparib including thrombocytopenia (33.8%), anemia (25.3%) and neutropenia (19.6%). Most of the hematological laboratory abnormalities occurred within the first three treatment cycles. After dose adjustment, the incidence of hematological abnormalities was infrequent beyond cycle 3. We are reporting two cases of Grade III/IV neutropenia and thrombocytopenia in patients treated with niraparib in our institution. Unfortunately, one of the patients succumbed to septic shock secondary to right lower lobe pneumonia while severely neutropenic. The second patient's blood counts improved after discontinuing the medication and with supportive transfusions during the hospitalization.

Long-term clinical outcomes of [177Lu]Lu-DOTATATE in patients with metastatic neuroendocrine tumors.

The incidence of gastroenteropancreatic neuroendocrine tumors has been rising and these tumors are usually only diagnosed at a metastatic stage. Present first line treatments include somatostatin analogs, targeted therapies and peptide receptor radionuclide therapy. The Lutetium-177 [177Lu] based radiotracer [177Lu]Lu-DOTATATE has only been approved as first-line treatment of metastatic midgut NETs however its efficacy as a third line or above treatment in patients with non ileal primaries has not been tested. In our study, we identified 25 patients with histologically confirmed well-differentiated metastatic neuroendocrine tumors and administered [177Lu]Lu-DOTATATE as a second line, third line and fourth line treatment. Our study demonstrated a notable response in patients with non-ileal primaries and heavily pretreated disease, warranting further studies for additional cycles of treatment.

Prophylactic Anticoagulation in Patients With Pancreatic Adenocarcinoma: A Single Tertiary Care Center Retrospective QI Project.

BACKGROUND/AIM: A well-known complication of pancreatic adenocarcinoma (PDAC) is venous thromboembolism (VTE). The Khorana score is used as a tool to help determine the role of primary prophylaxis (PPx) in cancer patients with VTE. This study compared outcomes in PDAC patients who received primary PPx (anticoagulation) versus those who did not. PATIENTS AND METHODS: PDAC patients from 2017-2019 at Allegheny General Hospital were retrospectively reviewed. Descriptive statistics were presented via medians with interquartile ranges for continuous variables and percentages for categorical variables. Predictors of VTE development were determined using univariable and multivariable logistic regression models. T-tests and Chi-square tests were used to compare means and percentages, respectively. RESULTS: A total of 102 patients with full VTE PPx data were reviewed. At least one VTE event was identified in 29 patients (28.2%). A total of 4 out of these 29 patients (13.8%) were on PPx anticoagulation. Death secondary to VTE occurred in one patient without PPx. Two (2.0%) patients experienced bleeding events of those prescribed VTE PPx. On univariable analysis, stage IV disease, planned surgery, and unresectable disease were predictors of VTE development. On multivariate analysis, total pancreatectomy was a predictor of VTE development. There was no difference in average time to progression amongst patients who had developed VTE versus those who did not. CONCLUSION: The Khorana score for VTE PPx in PDAC patients in underutilized.

A randomized, phase II trial of oral azacitidine (CC-486) in patients with resected pancreatic adenocarcinoma at high risk for recurrence.

BACKGROUND: Of the only 20% of patients with resectable pancreatic ductal adenocarcinoma (rPDA), cancer recurs in 80% of cases. Epigenetic dysregulation is an early hallmark of cancer cells acquiring metastatic potential, and epigenetic modulators may reactivate tumor suppressor genes, delay recurrence, and sensitize PDA to future chemotherapy. METHODS: This was a randomized phase II study (NCT01845805) of CC-486 (oral DNA methyltransferase inhibitor azacitidine) vs. observation (OBS) in rPDA patients harboring high-risk features (stage pN1-2, R1 margins, or elevated CA 19-9 level) with no evidence of disease following standard adjuvant therapy. Patients were randomized to oral CC-486 treatment (300 mg daily on days 1-21 on a 28-day cycle) or OBS for up to 12 cycles or until disease relapse/unacceptable toxicities. Following recurrence, records of next-line therapies, imaging, and survival were obtained. The primary endpoint was progression-free survival (PFS)-time from randomization to recurrence (imaging/biopsy confirmed or death). Secondary endpoints included OS and PFS and ORR and metastatic PFS with subsequent next-line systemic therapy in metastatic setting. RESULTS: Forty-nine patients (24 in CC-486 arm, 25 in OBS arm) were randomized: median age 66 (range 36-81), 53% male, 73% node positive, 49% elevated CA 19-9, 20% R1 resection, 63% and 100% received perioperative concurrent chemoradiation and chemotherapy, respectively. Median time from surgery to randomization was 9.6 mo (range 2.9-36.8). For the CC-486 arm, median treatment duration was 5.6 mo (range 1.3 to 12.8) with 14 treatment-related grade 3 or 4 AEs among 5 patients (22%) resulting in dose-reduction. Four patients (17%) discontinued therapy due to AEs. With median follow-up of 20.3mo (IQR 12.8, 41.4), 38 (79%) of evaluable patients recurred (34 imaging-confirmed, 4 clinically). Median PFS in imagining-confirmed cases was 9.2 and 8.9mo (HR 0.94, 95% CI 0.46-1.87, p = 0.85) for CC-486 and OBS patients, respectively. Median OS (2-yr OS%) was 33.8 (50%) and 26.4 mo (61%) in CC-486 and OBS patients, respectively. (HR 0.98, 95% CI 0.46-2.05, p = 0.96). ORR with subsequent chemotherapy in the metastatic setting was minimal in both arms. CONCLUSIONS: Treatment with CC-486 following adjuvant therapy did not prolong time-to-relapse in patients with high-risk rPDA or improve disease response on 1st-line metastatic therapy.

Chemotherapy use in early stage anal canal squamous cell carcinoma and its impact on long-term overall survival,,.

BACKGROUND: The standard of care for non-metastatic squamous cell carcinoma of the anal canal (SCCA) is concurrent chemoradiotherapy. It is postulated that chemotherapy could be omitted for the earliest stages without worsening outcomes. METHODS: We queried the NCDB from 2004-2016 for patients with cT1N0M0 SCCA treated non-operatively with radiation, with and without chemotherapy, and at least two months of follow-up. Of the 2,959 patients meeting eligibility, 92% received chemotherapy (n = 2722) and 8% (n = 237) did not. Most patients were white (n = 2676), female (n = 2019), had private insurance (n = 1507) and were treated in a comprehensive cancer center (n = 1389). Average age was 58.5 years. RESULTS: Predictors of chemotherapy omission were age > 58 years (OR 0.66, 95% CI [0.49-0.90], P = 0.0087), higher comorbidity score (OR 0.62, 95% CI [0.38-0.99], P = 0.0442), African American race (OR 0.57, 95% CI [0.36-0.90], P = 0.0156) and treatment at the start of the study period (OR 1 for years 2004-2006). HR for single-agent chemotherapy was 0.70 (95% CI [0.50-0.96], P = 0.0288) and 0.48 for multi-agent (95% CI [0.38-0.62], P <0.0001). Overall survival was 86% in those that received chemotherapy vs 65% in those who did not (P <0.0001). CONCLUSIONS: In conclusion, patients with early-stage squamous cell cancer of the anus who are treated with combination chemoradiation continue to demonstrate better overall survival than those who undergo radiotherapy alone.

A Rare Case of Locally Advanced Primary Small Cell Neuroendocrine Carcinoma of the Adrenal Gland.

BACKGROUND/AIM: Primary small cell neuroendocrine carcinoma (SCNEC) of the adrenal gland is extremely rare with limited reports in the literature. There remain no definitive treatment guidelines, largely due to the rarity of the malignancy. CASE REPORT: We present the case of a 62-year-old Caucasian male who presented with low back pain and was found to have a large retroperitoneal mass arising from the left adrenal gland, measuring 18.3 × 12.2 centimeters (cm). Biopsy was consistent with small cell carcinoma/high grade neuroendocrine carcinoma. Staging workup including CT chest and bone scan was negative. The patient was treated with chemotherapy, radiation therapy, and surgery; complete pathological response of the left adrenal tumor was achieved. Surveillance imaging every three months continued to show no evidence of recurrent disease. CONCLUSION: Primary SCNEC of the adrenal gland is rare and lacks standard treatment guidelines. Our case represents a possible treatment approach that may provide better clinical outcomes, however, further investigations are necessary to help define ideal treatment guidelines.

Retrospective review of total neoadjuvant therapy.

BACKGROUND: Neoadjuvant chemoradiotherapy (nCRT) followed by resection and postoperative multi-agent chemotherapy (maChT) is the standard of care for locally advanced rectal cancer. Using this approach, maChT administration can be delayed for several months, leading to concern for distant metastases. To counteract this, a novel treatment approach known as total neoadjuvant therapy (TNT) has gained popularity, in which patients receive both maChT and nCRT prior to resection. We utilized the National Cancer Database to examine temporal trends in TNT usage, and any potential effect on survival. AIM: To study the temporal trends in the usage of TNT and evaluate its efficacy compared to neoadjuvant chemoradiation. METHODS: We queried the National Cancer Database for patients with locally advanced rectal cancer, Stage II-III, from 2004-2015 treated with nCRT or TNT. TNT was defined as maChT initiated ≥ 90 d prior to nCRT initiation. Overall survival was calculated from the date of diagnosis to the date of last contact or death using Kaplan-Meier curves to present the cumulative probability of survival, with log-rank statistics to assess significance. Multivariable cox regression was used to identify predictors of survival and propensity score analysis accounted for bias. RESULTS: We identified 9066 eligible patients, with 8812 and 254 patients receiving neoadjuvant chemoradiation followed by maChT and TNT, respectively. Nodal involvement, stage III disease, and treatment in recent years were predictive of TNT use. There was greater use of TNT with more advanced stage, specifically > 1 node involved (odds ratio [OR] = 2.88, 95% confidence interval [CI]: 2.11-3.93, P < 0.01) and stage III disease (OR = 2.88, 95%CI: 2.11-3.93, P < 0.01). From 2010 to 2012 the use of TNT increased (OR = 2.41, 95%CI: 1.27-4.56, P < 0.01) with a greater increase from 2013 to 2015 (OR = 6.62, 95%CI: 3.57-12.25, P < 0.01). Both the TNT and neoadjuvant chemoradiation arms had a similar 5-year survival at 76% and 78% respectively. Multivariable analysis with propensity score demonstrated that increased age, high comorbidity score, higher grade, African American race, and female gender had worse overall survival. CONCLUSION: Our data demonstrates a rising trend in TNT use, particularly in patients with worse disease. Patients treated with TNT and nCRT had similar survival. Randomized trials evaluating TNT are underway.

Management of Well-differentiated Gastroenteropancreatic Neuroendocrine Tumors (GEPNETs): A Review.

PURPOSE: Neuroendocrine tumors (NETs) are heterogeneous tumors that arise from the neuroendocrine cells of the digestive tract and other organs, such as the lung, ovary, and thyroid glands. They can be well differentiated or poorly differentiated, and management of these tumors differs for each histologic subtype. We have performed a review of NETs and focused on management of well-differentiated gastroenteropancreatic neuroendocrine tumors (GEPNETs) and carcinoid syndrome. METHODS: A PubMed search was performed to obtain articles on the management of well-differentiated NETs. Using the key words neuroendocrine tumors, carcinoid, pNET, octreotide, somatostatin analogues, and radiolabeled therapy, we reviewed Phase II and III trials that were published over the past 30 years. We also reviewed guidelines from the European Neuroendocrine Tumor Society, North America Neuroendocrine Tumor Society, and National Comprehensive Cancer Network in our search. FINDINGS: NETs are usually slow-growing tumors that remain asymptomatic for a long duration and can be either nonfunctioning or functioning. Surgical resection is recommended for locoregional disease, impending obstruction, symptom control, and advanced disease. Nonsurgical treatment options include somatostatin analogues (SSAs), multikinase inhibitors, targeted therapy, chemotherapy, and radiolabeled SSAs. Carcinoid syndrome is mainly treated with SSAs. IMPLICATIONS: Although GEPNETs are slow-growing tumors, most patients are diagnosed with metastatic disease, and therefore it is important that the management of each patient be discussed in a multidisciplinary setting to optimize the treatment strategy. Patients should be considered for clinical trials and refractory cases referred to a specialty center.

Surgical adjuvant therapy for colorectal cancer: current approaches and future directions.

Colon cancer is the fourth most common cancer worldwide. The role of systemic adjuvant chemotherapy in colorectal cancer patients with lymph node involvement has been established in a large number of clinical trials. However, its role in stage II colorectal cancer is less well established. 5-Fluorouracil has been the mainstay of therapy for the last four decades. With the development of novel chemotherapy and biological agents, we have entered into a new era for the treatment of colorectal cancer. The combination of adjuvant 5-fluorouracil, leucovorin, and oxaliplatin has been shown to significantly improve disease-free survival and is now considered the standard of care for completely resected colon cancer in healthy patients. For rectal cancer patients with locally advanced tumors, neoadjuvant chemoradiation followed by adjuvant chemotherapy after surgery is the mainstay of treatment. The availability of oral chemotherapy agents has helped with the ease of administration and avoidance of indwelling catheters. A number of national clinical trials are under way to determine the role of targeted agents in combination with chemotherapy. The goal is to develop a regimen that would improve survival without excessive toxicity while maintaining quality of life. Patients should be encouraged to participate in clinical trials whenever feasible. Despite the advances, many patients will develop recurrent disease. It is of utmost importance to develop molecular markers that could predict which patients are at high risk for disease recurrence. Clinical trials are under way to address this issue. Thus, it will be advantageous to be able to tailor therapy individually, according to the risk of recurrence.

Aberrant Wnt/beta-catenin signaling in pancreatic adenocarcinoma.

Wnt/beta-catenin signaling plays an important role in normal development. However, its aberrant activation is associated with several cancers. The aim of this study is to examine the Wnt/beta-catenin pathway in patients with advanced pancreatic adenocarcinoma (n = 31). Paraffin sections from tumors (n = 16) and normal pancreata (n = 3) were used to determine the localization of beta-catenin. An additional 15 frozen tumors, adjacent normal pancreata (n = 5), or normal pancreata (n = 4) were utilized for protein isolation. Tumors were also examined for mutations in exon 3 of the CTNNB1 gene. More than 65% of the tumors showed an increase in total beta-catenin, consistent with its enhanced membranous, cytoplasmic, and nuclear localization, but only two showed mutations in CTNNB1. The majority of the remaining tumors demonstrated concurrent increases in Wnt-1 and frizzled-2 (positive regulators) and a decrease in Ser45/Thr41-phospho-beta-catenin. Electrophoretic mobility shift assay demonstrated beta-catenin-T-cell factor binding in tumors only. Adenomatous polyposis coli and axin, which are both negative regulators, remained unchanged. Unexpectedly, total glycogen synthase kinase-3beta protein was elevated in these tumors. Elevated levels of E-cadherin were also observed, although E-cadherin-beta-catenin association in tumors remained unaffected. Thus, Wnt/beta-catenin activation was observed in 65% of pancreatic adenocarcinomas, independently of beta-catenin gene mutations in most tumors.

Morpholino oligonucleotide-triggered beta-catenin knockdown compromises normal liver regeneration.

BACKGROUND/AIMS: Wnt/beta-catenin activation is seen during early liver regeneration (LR) observed as stabilization and translocation to the nucleus followed by an overall decrease. However, beta-catenin continues to be in hepatocyte nucleus and membrane, secondary to its increased gene expression at 6-72 h. METHODS: In the present study, we examined the effect of ablating beta-catenin transcription on LR. Twelve male fisher rats were subjected to two-third partial hepatectomy followed by administration of beta-catenin antisense phospho-morpholino oligonucleotide (AS) in six or mismatch control (CON) injection in the remaining 6 via superior mesenteric vein. Three animals from each group were sacrificed at 24 h and 7 days for liver assessment. RESULTS: AS group exhibited a significant decrease in total beta-catenin at 24 h. A significant decrease in liver/body weight ratio was also observed in the AS group at 24 h and 7 days that was due to decreased proliferation. Among the targets of this pathway c-myc and uPAR levels showed significant decrease while cyclin-D1 remained unaffected. CONCLUSIONS: We demonstrate the importance of beta-catenin in early liver regeneration especially in hepatocyte proliferation. Also, c-myc and uPAR might be crucial downstream effectors of beta-catenin during liver regeneration.

Epidermal growth factor receptor: a novel target of the Wnt/beta-catenin pathway in liver.

BACKGROUND & AIMS: Wnt/beta-catenin activation is observed in normal liver development, regeneration, and liver cancer. Our aim was to elucidate the regulation and mechanism of this pathway in liver. METHODS: We report the generation and characterization of liver-specific nonmutated beta-catenin-overexpressing transgenic mice. Transgenic livers were examined for their morphology and phenotype by histology, proliferation, apoptosis, and microarray analysis. RESULTS: Transgenic livers displayed a significant increase in cytoplasmic, membranous, and nuclear beta-catenin in hepatocytes as compared with their wild-type littermates, which display a predominant membranous localization only. A 15%-20% increase in the liver weight-body weight ratio was evident in transgenic mice secondary to increased hepatocyte proliferation. Microarray analysis showed differential expression of approximately 400 genes in the transgenic livers. Epidermal growth factor receptor RNA and protein and increased levels of activated epidermal growth factor receptor and Stat3 were observed in the transgenic livers. Epidermal growth factor receptor promoter analysis showed a T-cell factor-binding site, and subsequent reporter assay confirmed epidermal growth factor receptor activation in response to Wnt-3A treatment that was abrogated by frizzled related protein 1, a known Wnt antagonist. Epidermal growth factor receptor inhibition successfully decreased liver size in transgenic mice. Next, 7 of 10 hepatoblastomas displayed simultaneous beta-catenin and epidermal growth factor receptor up-regulation, thus suggesting a strong relationship between these 2 proteins in tumors. CONCLUSIONS: beta-Catenin transgenic mice show an in vivo hepatotrophic effect secondary to increased basal hepatocyte proliferation. Epidermal growth factor receptor seems to be a direct target of the pathway, and epidermal growth factor receptor activation might contribute toward some mitogenic effects of increased beta-catenin in liver: epidermal growth factor receptor inhibition might be useful in such states.