Changes in fears and worries related to COVID-19 during the pandemic among current employees in Japan: a 5-month longitudinal study.

OBJECTIVES: This study investigates and describes the time course of fears and worries about COVID-19 among current employees during this outbreak. STUDY DESIGN: This was a longitudinal study. METHODS: This study was a part of the Employee Cohort Study in Japan. The study comprised 4120 individuals from February 2019. A baseline survey in March 2020, a 2-month follow-up survey in May 2020, and a 5-month follow-up survey in August 2020 were conducted. Questions surveyed respondents' global fear and worry and six items related to COVID-19. A mixed model for repeated measures of an analysis of variance was used. RESULTS: A total of 1421 respondents completed the baseline survey. At 2- and 5-month follow-ups, 1032 and 1181 respondents completed surveys, respectively. Of those, 64 and 33 individuals who were temporarily laid off or on leave were recorded as missing values. Global fear and worry about COVID-19 significantly increased from March to August 2020. Fears of personal or family infection, limiting one's activities and national and local government policies also significantly increased with time. In contrast, fears of lack of knowledge and difficulty of obtaining hygiene products significantly decreased. CONCLUSION: To conduct efficient risk communication during a pandemic, knowing the concerns of the populace, providing correct information and a sufficient supply of products, and setting clear guidelines are essential.

Effects of sugammadex on incidence of postoperative residual neuromuscular blockade: a randomized, controlled study.

BACKGROUND: This study aimed to investigate whether reversal of rocuronium-induced neuromuscular blockade with sugammadex reduced the incidence of residual blockade and facilitated operating room discharge readiness. METHODS: Adult patients undergoing abdominal surgery received rocuronium, followed by randomized allocation to sugammadex (2 or 4 mg kg(-1)) or usual care (neostigmine/glycopyrrolate, dosing per usual care practice) for reversal of neuromuscular blockade. Timing of reversal agent administration was based on the providers' clinical judgement. Primary endpoint was the presence of residual neuromuscular blockade at PACU admission, defined as a train-of-four (TOF) ratio <0.9, using TOF-Watch® SX. Key secondary endpoint was time between reversal agent administration and operating room discharge-readiness; analysed with analysis of covariance. RESULTS: Of 154 patients randomized, 150 had a TOF value measured at PACU entry. Zero out of 74 sugammadex patients and 33 out of 76 (43.4%) usual care patients had TOF-Watch SX-assessed residual neuromuscular blockade at PACU admission (odds ratio 0.0, 95% CI [0-0.06], P<0.0001). Of these 33 usual care patients, 2 also had clinical evidence of partial paralysis. Time between reversal agent administration and operating room discharge-readiness was shorter for sugammadex vs usual care (14.7 vs. 18.6 min respectively; P=0.02). CONCLUSIONS: After abdominal surgery, sugammadex reversal eliminated residual neuromuscular blockade in the PACU, and shortened the time from start of study medication administration to the time the patient was ready for discharge from the operating room. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov:NCT01479764.

X-chromosome-linked inhibitor of apoptosis as a key factor for chemoresistance in clear cell carcinoma of the ovary.

BACKGROUND: X-chromosome-linked inhibitor of apoptosis (XIAP) is one of the anti-apoptotic proteins leading to chemoresistance in several cancers. The aim of this study is to evaluate the impact of XIAP expression upon ovarian clear cell carcinoma (CCC) that has a platinum-resistant phenotype. METHODS: Tissue microarrays made from 90 CCC patients were analysed for immunohistochemical expression levels of XIAP, c-Met, p-Akt and Bcl-XL. In addition, CCC cell lines were evaluated whether XIAP silencing could modulate sensitivity to platinum agent in vitro. RESULTS: High XIAP expression was observed in 30 (33%) of 90 CCC cases, and was associated with c-Met (<0.01) and Bcl-XL (<0.01) expression. Cases with high XIAP expression had lower response rate to primary platinum-based chemotherapy (10% vs 65%, P=0.02). In stages II-IV tumours, high XIAP expression was related with worse progression-free survival (PFS, P=0.02). Furthermore, high XIAP expression was identified as an independent worse prognostic factor for PFS and overall survival. Finally, downregulation of XIAP using XIAP-specific small interfering RNA increased sensitivity to cisplatin in human cancer cells derived from CCC. CONCLUSIONS: X-chromosome-linked inhibitor of apoptosis expression was correlated with chemoresistance of primary chemotherapy, and identified as a prognostic marker for CCC. X-chromosome-linked inhibitor of apoptosis could be a candidate for new therapeutic target in CCC.

Molecular analysis of cytosolic and mitochondrial malate dehydrogenases isolated from domestic cats (Felis catus).

Malate dehydrogenase (MDH) plays crucial roles in energy and cellular metabolism. In this study, we describe the identification and characterization of cytosolic MDH (MDH1) and mitochondrial MDH (MDH2) in liver of domestic cat (Felis catus). To clone the feline full-length MDH genes, we performed rapid amplification of cDNA ends. The MDH1 gene encoded a protein of 334 amino acids and the MDH2 gene encoded a protein of 338 amino acids, containing a 24-amino acid mitochondrial target sequence. The feline MDH1 and MDH2 proteins shared, respectively, 98.8-93.7 and 96.7-94.4% homology with dog, giant panda, horse, cow, pig, human, mouse, and rat. The feline MDHs had a highly conserved active motif, which contained important residues for catalysis and coenzyme binding. The putatively acetylated lysine residues that regulate MDH activity were also conserved at K118, K121, and K298 in MDH1, and K185, K301, K307, and K314 in MDH2. Both MDH1 and MDH2 mRNAs were ubiquitously expressed, but these expression levels varied in a tissue-specific manner. Both MDH genes were expressed at considerably high levels in heart and skeletal muscle, but at low levels in lung and spleen.

Ovarian yolk sac tumor associated with pregnancy: a case report and review of the literature.

BACKGROUND: Ovarian yolk sac tumor (YST) that is diagnosed during pregnancy is extremely rare. CLINICAL CASE: A 22-year-old pregnant woman diagnosed with Stage IIIc YST at 17 weeks of gestation is presented. A 20-cm multilocular cystic tumor containing solid components with massive ascites was detected. Subsequently she underwent left salpingo-oophorectomy and cytoreductive surgery for peritoneal dissemination at 18 weeks of gestation, and the tumors were diagnosed as YST. After vaginal termination at 20 weeks of gestation, she received five cycles of combination therapy with bleomycin, etoposide, and cisplatin. There was no evidence of recurrence at 85 months after primary treatment. CONCLUSION: Considering the rarity, treatment strategy for advanced-staged YST should be further investigated in international collaborative studies.

Urinary steroid profiling using liquid chromatography-tandem mass spectrometry for the diagnosis of canine Cushing's syndrome.

Serum cortisol measurements by chemiluminescence enzyme immunoassay (CLEIA) are widely used to diagnose hypercortisolism (HC) or Cushing's syndrome in dogs. However, they are associated with problems such as the need for multiple blood collections under stressful conditions or cross-reactivity between hormones. Therefore, a less invasive and more accurate diagnostic method is required. This study aimed to develop a urinary steroid profile analysis method using liquid chromatography-tandem mass spectrometry (LC/MS/MS) and to evaluate its clinical usefulness. Sixty-five healthy dogs and 38 dogs with suspected HC were included in the study. Using LC/MS/MS, the levels of 11 steroid hormones in the urine were determined. We established the upper limit of the reference interval for each urinary steroid-to-creatinine ratio and evaluated their diagnostic performances. The levels of the five steroid hormones were significantly higher in the 14 dogs with HC than in the 24 dogs with mimicking HC and 65 healthy dogs. The urinary corticosterone-to-creatinine ratio showed the highest diagnostic accuracy (area under the curve, 0.96). A significant correlation was seen between urinary cortisol concentrations measured by LC/MS/MS and CLEIA (rs = 0.88, P <0.001), although the CLEIA measurements were significantly higher than the LC/MS/MS measurements (P <0.001). LC/MS/MS-based urinary steroid profiles are a promising tool for diagnosing canine HC.

Moderate physical exercise results in increased cell activity in articular cartilage of the knee joint in rats.

BACKGROUND: Moderate exercise regimens have shown minor positive effects on matrix turnover in articular cartilage (AC), while effects at cellular level, e.g. proliferation, are scarcely described. AIM: The aim of this study was to investigate the effects of moderate exercise on cell proliferation and recruitment of cells possibly active in regeneration in different regions of cartilage in the rat knee joint. METHODS: Eighteen rats were orally given 5-bromo-2-deoxyuridine (BrdU) for 14 days for in vivo DNA labeling. Nine rats underwent treadmill training for 50 min/day, 5 days/week (exercise group), and 9 rats served as controls (no exercise). Animals were sacrificed after 14, 56 and 105 days, and knee joints were harvested. BrdU+ cells were visualized immunohistochemically (IHC) and counted in AC, posterior stem cell niche (PN), potential migration route (PMR; area between PN and the AC border), potential migration area (PMA; region between PN and AC including PN) and epiphyseal cartilage plate (EP) of the tibia and femur. RESULTS: Compared to controls, in the exercise group BrdU+ cells/mm(2) were increased on days 14 (p = 0.022) and 105 (p = 0.045) in AC of the tibia and on day 105 (p = 0.014) in AC of the femur. BrdU+ cell numbers were increased in the PMR region of the tibia on days 14 (p = 0.023) and 105 (p = 0.0018) and in the PMR region of the femur on day 105 (p = 0.0099) as well as in the PMA region of the tibia (p = 0.0008) and femur (p = 0.0080) on day 105. No significant differences in BrdU+ cells/mm(2) were seen in PN or EP between the groups at any time point. Regarding collagen 2A1 expression and proteoglycan accumulation, no significant differences between groups were detected. CONCLUSIONS: The results indicate increased cell activity in AC in response to physical exercise and may help to understand the complexity of AC regeneration in the normal mammal knee joint.

New 2,3-diaminopropionic acid inhibitors of AGE and ALE formation.

Novel 2,3-diaminopropionic acid-based molecules were synthesised and tested successfully as glyoxal/methylglyoxal scavengers and as AGE inhibitors. Addition of an 8-hydroxyquinoline moiety led to an increase of the overall activity. The compounds tested in this study were also proved to be efficient in trapping ALE precursor malondialdehyde.

Complete remission of recurrent and refractory ovarian cancers using weekly administration of bevacizumab and gemcitabine/oxaliplatin: report of two cases.

BACKGROUND: A combination therapy with gemcitabine and oxaliplatin (GEMOX) yielded a moderate activity in platinum-resistant ovarian cancers; however, frequent severe toxicities, such as thrombocytopenia and neurotoxicity, were observed. A certain modification of schedule might therefore facilitate the clinical application of the regimen. The authors report two cases that achieved complete response to a weekly administration of bevacizumab and GEMOX. MATERIALS AND METHODS: Two patients with platinum-resistant recurrent ovarian cancers received a weekly regimen of GEMOX with bevacizumab: 2 mg/kg of bevacizumab, 300 mg/m2 of gemcitabine, and 30 mg/m2 of oxaliplatin, three weeks on and one week off, Q4 weeks. Complete remission was observed after three to four courses of therapy. Hematologic and non-hematologic toxicities more than grade 2 were not observed during chemotherapy. The patients are now without tumor progression more than 12 months after initiation of therapy. CONCLUSION: Weekly administration of bevacizumab and GEMOX had potential activity in recurrent and refractory ovarian carcinomas. These findings warrant necessity of further trial in such clinical settings.

Identification of an imprinted U2af binding protein related sequence on mouse chromosome 11 using the RLGS method.

A new imprinted gene has been discovered in mice using the technique of restriction landmark genomic scanning (RLGS) with methylation sensitive enzymes. Eight out of 3,100 strain-specific NotI and BssHII spots were identified as imprinted in reciprocal F1 hybrids. Subsequently, we isolated a genomic clone for one locus on proximal chromosome 11 near the Glns locus, an imprinted region in uniparental disomic mice, and its corresponding cDNA clone. Expression of this transcript from the paternal allele was established using RT-PCR of reciprocal F1-hybrid mice. The amino-acid sequence deduced from the cDNA showed significant homology to the U2 small nuclear ribonucleoprotein auxiliary factor 35 kDa subunit.

The reeler gene encodes a protein with an EGF-like motif expressed by pioneer neurons.

We have identified a strong candidate cDNA for the mouse reeler gene. This 5 kb transcript encodes a 99.4 kD protein consisting of 881 amino acids and possessing two EGF-like motifs. We assayed two independent mutant alleles--'Jackson reeler', which has a deletion of the entire gene, and 'Orleans reeler' which exhibits a 220 bp deletion in the open reading frame, including the second EGF-like motif and resulting in a frame shift. In situ hybridization reveals that the transcript is detected exclusively in the pioneer neurons which guide neuronal cell migration along the radial array. Our findings offer an explanation for how the reeler mutant phenotype causes a disturbance of the complex architecture of the neuronal network.

A genetic linkage map of the Syrian hamster and localization of cardiomyopathy locus on chromosome 9qa2.1-b1 using RLGS spot-mapping.

The Syrian cardiomyopathic hamster (BIO14.6) has an inherited form of progressive myocardial necrosis and congestive heart failure. Although widely studied as an animal model for human hypertrophic cardiomyopathy, further genetic analysis has been limited by a scarcity of DNA markers. Until now, only six autosomal linkage groups have been described and the number of polymorphic loci was extremely limited. In this study, we applied the restriction landmark genome scanning (RLGS) spot-mapping method to construct a genetic map of the Syrian hamster (Mesocricetus auratus) using 72 back-cross progeny. Although the polymorphic rate is very low (3-7%) between the strains, 531 polymorphic spots/loci were mapped, showing the power of this approach and reasonable applicability to other organisms lacking a well-defined genetic map. Further, the spot markers which flank the cardiomyopathy (cm) locus were cloned to determine the chromosomal location of cm by fluorescent in situ hybridization (FISH) analysis, resulting in the assignment of the locus to the centromeric region of hamster chromosome 9qa2.1-b1. Several candidate genes responsible for hypertrophic cardiomyopathy in humans have been excluded.

Prognostic value of left atrial stiffness estimated using echocardiography in dogs with myxomatous mitral valve disease.

INTRODUCTION: No studies have investigated the prognostic value of left atrial stiffness (LASt) estimated using echocardiography in dogs with myxomatous mitral valve disease (MMVD). ANIMALS: Seventy-two dogs had MMVD and 46 dogs were healthy dogs. MATERIALS AND METHODS: Clinical retrospective cohort study. The survival information of MMVD dogs that underwent echocardiographic examination was obtained. The peak velocities of early diastolic transmitral flow (E) and mitral annular motion as determined by pulsed wave Doppler (E') were determined. The left atrial reservoir strain (εS) was determined by two-dimensional speckle tracking echocardiography of the left atrium. The LASt was estimated by the formula: E/E'/εS. The 95% prediction interval of LASt was computed from the data of the healthy dogs. RESULTS: Seventeen dogs having MMVD died of cardiac-related causes with 55 MMVD dogs censored. The MMVD dogs with LASt > its 95% upper prediction limit (LASt > 0.56; n = 26; median survival time, 484 days; 95% confidence interval, 283 days-indeterminable) had shorter survival times (P<0.001) than those with LASt ≤ its 95% upper prediction limit (LASt ≤ 0.56; n = 46; median survival time, >1112 days; 95% confidence interval, indeterminable). Multivariable Cox's proportional hazard analysis demonstrated that the ratio of the left atrial dimension to the aortic annulus dimension and LASt were independent predictors of cardiac-related death among conventional echocardiographic indices, εS and LASt in MMVD dogs. CONCLUSIONS: In dogs with MMVD, increased LASt estimated using echocardiography is an independent predictor of cardiac-related death, and LASt can be more useful for prognostication than εS.

Evaluation of responses to immunosuppressive therapy in dogs with suspected non-regenerative immune-mediated anaemia: 11 cases (2012-2018).

OBJECTIVES: We aimed to determine the response time to immunosuppressive therapy and time required to achieve a 5% increase in haematocrit among dogs with non-regenerative immune-mediated anaemia. MATERIALS AND METHODS: Client-owned dogs diagnosed with non-regenerative immune-mediated anaemia in Hokkaido University Veterinary Teaching Hospital between December 2012 and May 2018 were enrolled. The first treatment regimen included prednisolone (2 mg/kg/day) and ciclosporin (up to 10 mg/kg/day) for 8 weeks. Dogs that did not respond to the first regimen proceeded to the second regimen comprising prednisolone and mycophenolate mofetil (15 mg/kg, twice a day). Reticulocyte count and haematocrit were monitored every 1 to 2 weeks. Treatment response was defined as an absolute reticulocyte count more than 60×103 /µL or increasing haematocrit. RESULTS: During the study period, 23 dogs fulfilled the inclusion criteria for non-regenerative immune-mediated anaemia. Twelve dogs were excluded from this study for various reasons and response to therapy was evaluated in the remaining 11 dogs. Treatment responses were observed in 8 of 11 dogs, and the median time to response was 39.5 days (range 8 to 92 days). Two responders were unable to continue the first treatment regimen and were switched to the second regimen owing to anorexia and nausea, possibly induced by ciclosporin; withdrawal of ciclosporin improved their symptoms. The time required to achieve a 5% increase in haematocrit was assessed in the other six dogs, with a median of 55.5 days (range 8 to 135 days). CLINICAL SIGNIFICANCE: Here we report the response to a standardised treatment protocol in dogs with non-regenerative immune-mediated anaemia. Knowledge of potential side effects and expected therapeutic outcomes may be of use for veterinary practitioners treating this condition.

Large cell neuroendocrine carcinoma arising in mature cystic teratoma: a case report and review of the literature.

BACKGROUND: Malignant transformation of ovarian mature cystic teratoma is rare, and occurs in approximately 1% of all cases. The most common histology arising in mature cystic teratoma is squamous cell carcinoma. Less frequently, malignant transformation is represented by an endocrine tumor. To date, only five cases of large cell neuroendocrine carcinoma (LCNC) arising in a mature cystic teratoma of the ovary have been reported. CLINICAL CASE: A 69-year-old woman presented with a 15-cm left ovarian mass, and was diagnosed with Stage IV large cell carcinoma neuroendocrine carcinoma (LCNC) arising in mature cystic teratoma (MCT) of the left ovary. The patient received adjuvant chemotherapy with paclitaxel and carboplatin, however, residual tumors increased in size. Six months after the debulking surgery she succumbed to the disease. A literature review revealed LCNC of the ovary showed excessively aggressive phenotype in malignant transformation from ovarian mature cystic teratoma. CONCLUSION: The present case of LCNC arising in MCT had an exceedingly poor prognosis, which was suggested in the previous five cases reported.

Prognosis of high-grade endometrial cancer: a comparison of serous-type and clear cell type to grade 3 endometrioid-type.

OBJECTIVE: To evaluate prognosis of high-grade endometrial cancers, comparing serous (SC) and clear cell (CCC) types to grade 3 endometrioid carcinoma (ECG3). METHODS: Among patients with endometrial cancer treated in two decades, medical records of patients with high-grade endometrial cancer were retrospectively investigated. RESULTS: Of 447 endometrial cancers, 107 (24%) high-grade endometrial cancers were identified, with the increasing incidence in the last decade (28% vs 19%; p = 0.026). There were 24 SC, 14 CCC and 69 ECG3. Median age was 62, 68, and 61 years, respectively, with the CCC type showing an elder age than the ECG3 type (p = 0.012). The rates of patients with Stage IIIc-IV, lymph node assessment or complete resection at primary surgery, and post-operative chemotherapy were not significantly different; however, response rate to first-line chemotherapy in patients with measurable disease was lower in SC than ECG3 (3 / 11, 27% vs 14 / 19, 74%; p = 0.037), regardless of regimens. Five-year overall survival (OS) was 40%, 71%, and 71% respectively, and five-year progression-free survival (PFS) was 25%, 71%, and 61%, respectively, showing SC with worse prognosis than ECG3 on both OS (p = 0.026) and PFS (p = 0.0028). According to the multivariate analysis, age > or = 70, Stage IIIc-IV and incomplete resection were independent prognostic factors on poor OS, whereas SC, Stage IIIc-IV and incomplete resection were on poor PFS. CONCLUSIONS: The increasing trend of high-grade endometrial cancer and different outcomes according to histological subtypes, especially poor PFS and chemotherapeutic response in SC, were suggested.

Normal serum CA125 half-life and normal serum nadir CA125 level in patients with ovarian cancers.

The normal serum CA125 half-life and distribution of the normal serum nadir CA125 value in patients with epithelial ovarian carcinoma (EOC) have not been determined yet. Among patients with EOC, 41 patients met the inclusion criteria of the present study: the patients that underwent complete cytoreductive surgery and six cycles of platinum-containing chemotherapy, and who had no recurrent disease more than five years. Serum CA125 half-life (T1/2) during primary surgery and primary chemotherapy was calculated and serum nadir CA125 level was evaluated by logarithmic-transformed serum CA125. Median value of nadir CA125 was 7 U/ml (range 3-20 U/ml), and the mean ln (serum nadir CA125) was 1.96 +/- 0.45. Mean T1/2 was 10.4 days in all patients, and T1/2 value was associated with the preoperative serum levels of CA125. Predicted slope of CA125 regression curve was also influenced by the preoperative CA125 value. The present study provides fundamental information with regard to normal half-life time and normal nadir of CA125 in EOC patients.

Biological effect of tyrosine kinase inhibitors on three canine mast cell tumor cell lines with various KIT statuses.

Tyrosine kinase inhibitors (TKIs) can be important in the treatment of canine mast cell tumor (cMCT). Meanwhile, some TKIs have been identified as substrates for ABCB1. The inhibitory effect of four TKIs (axitinib, imatinib, masitinib, and vatalanib) for proliferation and phosphorylation of c-Kit receptor as well as the expression and function of ABCB1 were investigated in three cMCT cell lines (HRMC, VIMC1, and CMMC1). The IC(50) values of the TKIs in HRMC, the only cell line with wild-type KIT, were clearly higher than those in CMMC1 and VIMC1. In HRMC and CMMC1, both the growth and phosphorylation of c-Kit receptor were suppressed proportionally by the TKIs. VIMC1 required higher concentrations for the inhibition of c-Kit receptor phosphorylation than those in cell growth. The treatment with cyclosporine increased the effects of the TKIs on VIMC1 since ABCB1 was expressed in VIMC1. The results indicated that cMCT cell lines harboring wild-type KIT had lower sensitivity to TKIs. The growth of VIMC1 was seemingly reduced by TKIs through the inhibition of other tyrosine kinases than c-Kit receptor. There was little influence of ABCB1 on TKI effects to the proliferation of VIMC1. These results will be helpful to understand the different sensitivity to TKIs in cMCT patients.

Cell death signalling is competitively but coordinately regulated by repressor-type and activator-type ethylene response factors in tobacco (Nicotiana tabacum) plants.

Ethylene response factors (ERFs) comprise one of the largest transcription factor families in many plant species. Tobacco (Nicotiana tabacum) ERF3 (NtERF3) and other ERF-associated amphiphilic repression (EAR) motif-containing ERFs are known to function as transcriptional repressors. NtERF3 and several repressor-type ERFs induce cell death in tobacco leaves and are also associated with a defence response against tobacco mosaic virus (TMV). We investigated whether transcriptional activator-type NtERFs function together with NtERF3 in the defence response against TMV infection by performing transient ectopic expression, together with gene expression, chromatin immunoprecipitation (ChIP) and promoter analyses. Transient overexpression of NtERF2 and NtERF4 induced cell death in tobacco leaves, albeit later than that induced by NtERF3. Fusion of the EAR motif to the C-terminal end of NtERF2 and NtERF4 abolished their cell death-inducing ability. The expression of NtERF2 and NtERF4 was upregulated at the early phase of N gene-triggered hypersensitive response (HR) against TMV infection. The cell death phenotype induced by overexpression of wild-type NtERF2 and NtERF4 was suppressed by co-expression of an EAR motif-deficient form of NtERF3. Furthermore, ChIP and promoter analyses suggested that NtERF2, NtERF3 and NtERF4 positively or negatively regulate the expression of NtERF3 by binding to its promoter region. Overall, our results revealed the cell death-inducing abilities of genes encoding activator-type NtERFs, including NtERF2 and NtERF4, suggesting that the HR-cell death signalling via the repressor-type NtERF3 is competitively but coordinately regulated by these NtERFs.

Acceleration of intestinal polyposis through prostaglandin receptor EP2 in Apc(Delta 716) knockout mice.

Arachidonic acid is metabolized to prostaglandin H(2) (PGH(2)) by cyclooxygenase (COX). COX-2, the inducible COX isozyme, has a key role in intestinal polyposis. Among the metabolites of PGH(2), PGE(2) is implicated in tumorigenesis because its level is markedly elevated in tissues of intestinal adenoma and colon cancer. Here we show that homozygous deletion of the gene encoding a cell-surface receptor of PGE(2), EP2, causes decreases in number and size of intestinal polyps in Apc(Delta 716) mice (a mouse model for human familial adenomatous polyposis). This effect is similar to that of COX-2 gene disruption. We also show that COX-2 expression is boosted by PGE(2) through the EP2 receptor via a positive feedback loop. Homozygous gene knockout for other PGE(2) receptors, EP1 or EP3, did not affect intestinal polyp formation in Apc(Delta 716) mice. We conclude that EP2 is the major receptor mediating the PGE2 signal generated by COX-2 upregulation in intestinal polyposis, and that increased cellular cAMP stimulates expression of more COX-2 and vascular endothelial growth factor in the polyp stroma.