Proposal of an integrated staging system using albumin-bilirubin grade and serum alpha-fetoprotein values for predicting postoperative prognosis of recurrent hepatocellular carcinoma

BACKGROUND

Because repeat hepatectomy for recurrent hepatocellular carcinoma is a potentially invasive procedure, it is necessary to identify patients who truly benefit from repeat hepatectomy. Albumin-bilirubin grading has been reported to predict survival in patients with hepatocellular carcinoma. However, as prognosis also depends on tumor factors, a staging system that adds tumor factors to albumin-bilirubin grading may lead to a more accurate prognostication in patients with recurrent hepatocellular carcinoma.

METHODS

Albumin-bilirubin grading and serum alpha-fetoprotein levels were combined and the albumin-bilirubin-alpha-fetoprotein score was created ([albumin-bilirubin grading = 1; 1 point, 2 or 3; 2 points] + [alpha-fetoprotein<75 ng/mL, 0 points; ≥5, 1 point]). Patients were classified into three groups, and their characteristics and survival were evaluated. The predictive ability of the albumin-bilirubin-alpha-fetoprotein score was compared with that of the Cancer of the Liver Italian Program and the Japan Integrated Stage scores.

RESULTS

Albumin-bilirubin-alpha-fetoprotein score significantly stratified postoperative survival (albumin-bilirubin-alpha-fetoprotein score = 1/2/3: 5-year recurrence-free survival [%]: 22.4/20.7/0.0, p < 0.001) and showed the highest predictive value for survival among the integrated systems (albumin-bilirubin-alpha-fetoprotein score/Japan Integrated Stage/Cancer of the Liver Italian Program: 0.785/0.708/0.750).

CONCLUSIONS

Albumin-bilirubin-alpha-fetoprotein score is useful for predicting the survival of patients with recurrent hepatocellular carcinoma undergoing repeat hepatectomy.

A resected case of pancreatic head cancer developing 40 years after lateral pancreaticojejunostomy for chronic pancreatitis

A 72-year-old male patient presented to our department complaining of with upper abdominal pain and jaundice. He had a history of a side-to-side pancreaticojejunostomy performed 40 years previously for chronic pancreatitis. A diagnostic workup revealed a tumor 3 cm in size in the pancreatic head as the etiology of the jaundice. Subsequently, the patient was diagnosed with resectable pancreatic cancer. Following two cycles of neoadjuvant chemotherapy, an extended pancreatoduodenectomy was performed because of tumor invasion at the previous pancreaticojejunostomy site. Concurrent portal vein resection and reconstruction were performed. Pathological examination confirmed invasive ductal carcinoma (T2N1M0, Stage IIB). This case highlights the clinical challenges in pancreatic head carcinoma following a side-to-side pancreaticojejunostomy. Although pancreaticojejunostomy is believed to reduce the risk of pancreatic cancer in patients with chronic pancreatitis, clinicians should be aware that, even after this surgery, there is still a chance of developing pancreatic cancer during long-term follow-up.

Total Steroid Intake is Associated With Hospital Mortality in Patients With Pan-Peritonitis due to Colorectal Perforation

BACKGROUND

Patients with pan-peritonitis (PP) due to colorectal perforation have high mortality rate because colorectal perforation causes septic shock. The association between total steroid intake (TSI) and hospital mortality of such patients is not clear.

METHODS

One hundred forty-two patients who underwent surgery for PP due to colorectal perforation were reviewed. Patients were divided into two groups by 8000 mg of TSI. The cut-off value of TSI was determined using a receiver operating characteristic curve for hospital mortality.

RESULTS

The cut-off value of TSI for hospital mortality was 8000 mg. Patients with TSI>8000 mg had high rate of hemodialysis, hospital mortality, and elevated neutrophil ratio (>95%) compared with those with TSI≤8000 mg. Multivariate analyses revealed that TSI (>8000/≤8000, mg) (OR, 9.669; 95% CI, 1.011-92.49; P = .049) was significantly associated with hospital mortality as well as bleeding volume (>1000/≤1000, mL) (OR, 26.08; 95% CI, 3.566-190.4; P = .001), lymphocyte ratio (≤4/>4, %) (OR, 7.988; 95% CI, 1.498-42.58; P = .015) and C-reactive protein (≤7.5/>7.5, mg/dL) (OR, 41.66; 95% CI, 4.784-33.33; P = .001).

DISCUSSION

There was a significant association between TSI and hospital mortality in patients with PP due to colorectal perforation as well as intraoperative bleeding and systemic inflammatory markers.

N2 Lymph Node Metastasis Is a Useful Predictor of Recurrence in Patients With Stage III Rectal Cancer Undergoing Adjuvant Chemotherapy Using Tegafur-uracil/leucovorin

BACKGROUND/AIM

Fluoropyrimidine therapy or oxaliplatin combination therapy is recommended for patients with stage III colorectal cancer as adjuvant chemotherapy (AC). However, the criterion for selecting these regimens is still unclear in patients with stage III rectal cancer (RC). In order to select an appropriate regimen of AC for such patients, it is needed to identify characteristics associated with tumor recurrence.

PATIENTS AND METHODS

The records of 45 patients with stage III RC undergoing AC using tegafur-uracil/leucovorin (UFT/LV) were retrospectively reviewed. The cut-off value of characteristics was determined using a receiver operating characteristic curve for recurrence. Univariate analyses using Cox-Hazard model for predicting recurrence were performed with clinical characteristics. Survival analysis was performed using Kaplan-Meier method and log-rank test.

RESULTS

Thirty patients (66.7%) completed AC using UFT/LV. Fifteen patients (33.3%) did not complete AC because of adverse events, tumor recurrence and others. Sixteen patients (35.6%) had recurrence. Univariate analyses revealed that lymph node metastasis (N2/N1) (p=0.002) was associated with tumor recurrence. Survival analysis showed that lymph node metastasis (N2/N1) could stratify recurrence-free survival (p<0.001).

CONCLUSION

N2 lymph node metastasis can predict tumor recurrence in patients with stage III RC undergoing AC using UFT/LV.

Laparoscopic surgery reduced frequency of postoperative small bowel obstruction, and hospital stay compared with open surgery in a cohort of patients with colorectal cancer: a propensity score matching analysis

BACKGROUND

Laparoscopic surgery (LS) is reported to reduce postoperative complications and hospital stay compared with open surgery (OP). Because patient selection may have been biased in previous studies, propensity score matching (PSM) analysis was used in this study to test the benefits of LS compared with OP.

METHODS

A total of 759 patients with stage I-III colorectal cancer undergoing curative surgery were retrospectively reviewed. To minimize confounding bias between LS and OP groups, a 1:1 PSM analysis was performed based on adjuvant chemotherapy, age, albumin, body mass index, American Society of Anesthesiologists physical status depth of tumor, gender, lymph node dissection, maximum tumor size, obstructive tumor, previous abdominal surgery, pathological stage, tumor differentiation, and tumor location. Statistical analyses including chi-square test, Mann-Whitney U test, univariate analyses and Kaplan-Meier method and log-rank test were performed using the data after PSM to investigate the benefits of LS compared with OP.

RESULTS

After PSM analysis, 460 patients remained in the study. The LS group had lower intraoperative blood loss (34 ± 70 vs 237 ± 391, mL; P < 0.001), lower frequency of postoperative small bowel obstruction (SBO) (17/213 vs 30/230; P = 0.045), lower rate of nasogastric tube insertion (7/223 vs 17/213; P = 0.036), and shorter postoperative hospital stay (13 ± 10 vs 25 ± 47, day; P < 0.001) than the OP group. Univariate analyses showed that LS significantly reduced the risk of postoperative SBO (odds ratio [OR] 0.532; 95% confidence interval [CI] 0.285-0.995; P = 0.048) and nasogastric tube insertion (OR 0.393; 95% CI 0.160-0.967; P = 0.042) compared with OP. There were no significant differences in OS and RFS between the groups.

CONCLUSIONS

LS reduced intraoperative blood loss, frequency of postoperative SBO, rate of nasogastric tube insertion, and postoperative hospital stay compared with OP.

Surface Adsorption Properties and Layer Structures of Homogeneous Polyoxyethylene-Type Nonionic Surfactants in Quaternary-Ammonium-Salt-Type Amphiphilic Gemini Ionic Liquids with Oxygen- or Nitrogen-Containing Spacers

The amphiphilic ionic liquids containing an alkyl chain in molecules form nano-structure in the bulk, although they also show surface activity and form aggregates in aqueous solutions. Although insights into the layer structures of ionic liquids were obtained using X-ray and neutron scattering techniques, the nanostructures of ionic liquids remain unclear. Herein, the surface adsorption and bulk properties of homogeneous polyoxyethylene (EO)-type nonionic surfactants (C_xEO₆; x = 8, 12, or 16) were elucidated in quaternary-ammonium-salt-type amphiphilic gemini ionic liquids with oxygen or nitrogen-containing spacers [2C_n(Spacer) NTf₂; (Spacer) = (2-O-2), (2-O-2-O-2), (2-N-2), (2/2-N-2), (3), (5), or (6); n = 10, 12, or 14 for (2-O-2) and n = 12 for all other spacers] by surface tension, small- and wide-angle X-ray scattering, cryogenic transmission electron microscopy, and viscosity measurements. The surface tension of C₁₂EO₆ in 2C_n(Spacer) NTf₂ with oxygen-containing spacers increased with increasing concentration of C₁₂EO₆, becoming close to that of C₁₂EO₆ alone, indicating that the amphiphilic ionic liquid adsorbed at the interface was replaced with C_xEO₆. In contrast, both 2C_n(Spacer) NTf₂ with nitrogen-containing spacers and nonionic surfactants remained adsorbed at the interface at high concentrations. In the bulk, it was found that 2C_n(Spacer) NTf₂ formed layer structures, in which the spacing depended on the alkyl chain length of C_xEO₆. These insights are expected to advance the practical applications of amphiphilic ionic liquids such as ion permeation, drug solubilization, and energy delivery systems.

Tumor-associated macrophage-derived inflammatory cytokine enhances malignant potential of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an asbestos-related aggressive malignant neoplasm. Due to the difficulty of achieving curative surgical resection in most patients with MPM, a combination chemotherapy of cisplatin and pemetrexed has been the only approved regimen proven to improve the prognosis of MPM. However, the median overall survival time is at most 12 mo even with this regimen. There has been therefore a pressing need to develop a novel chemotherapeutic strategy to bring about a better outcome for MPM. We found that expression of interleukin-1 receptor (IL-1R) was upregulated in MPM cells compared with normal mesothelial cells. We also investigated the biological significance of the interaction between pro-inflammatory cytokine IL-1β and the IL-1R in MPM cells. Stimulation by IL-1β promoted MPM cells to form spheroids along with upregulating a cancer stem cell marker CD26. We also identified tumor-associated macrophages (TAMs) as the major source of IL-1β in the MPM microenvironment. Both high mobility group box 1 derived from MPM cells and the asbestos-activated inflammasome in TAMs induced the production of IL-1β, which resulted in enhancement of the malignant potential of MPM. We further performed immunohistochemical analysis using clinical MPM samples obtained from patients who were treated with the combination of platinum plus pemetrexed, and found that the overexpression of IL-1R tended to correlate with poor overall survival. In conclusion, the interaction between MPM cells and TAMs through a IL-1β/IL-1R signal could be a promising candidate as the target for novel treatment of MPM (Hyogo College of Medicine clinical trial registration number: 2973).

Efficacy and safety of nivolumab for malignant mesothelioma in the real world

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Background: Until recently, the standard treatment for advanced malignant pleural mesothelioma (MPM) was only cisplatin plus pemetrexed. Nivolumab, an anti-programmed death-1 monoclonal antibody, shows efficacy against pretreated MPM and has been approved in Japan, but the data regarding the efficacy and safety of nivolumab in MPM are limited to those from a small number of patients of the MERIT study. Therefore, it is important to accumulate real-world data on the efficacy and safety of nivolumab for MPM. Methods: We retrospectively analyzed all patients with MPM who received nivolumab at Hyogo College of Medicine Hospital from August 2018 to December 2018. Results: A total of 77 patients (61 males and 16 females) were included. There were 62, 10, and 5 patients with performance statuses of 0–1, 2, and 3, respectively. There were 63, 8, and 6 patients with epithelioid, sarcomatoid, and bi-phasic histologies, respectively. Nivolumab was administered as second-, third-, and ≥fourth-line treatment to 48, 15, and 11 patients, respectively. In 66 patients who were examined for efficacy, the response rate (RR) was 24.2% and the disease control rate (DCR) was 63.6%. By the histology type, the RR and DCR were 15.1% and 62.3% for the epithelioid type, 62.5% and 87.5% for the sarcomatoid type, and 20.0% and 40.0% for the bi-phasic type, respectively. The median progression-free survival (mPFS) was 4.1 months and the median overall survival (mOS) was 13.3 months. Analyzing the efficacy based on the neutrophil-to-lymphocyte ratio (NLR) in the peripheral blood, the RRswere 14.7% in the NLR≥3.5 group and 25.8% in the NLR < 3.5 group. The mPFS and mOS in the NLR≥3.5 group were 3.1 months and 11.4 months, respectively,whereas those in the NLR < 3.5 group were 5.6 months and not reached, respectively. There were no significant differences in the RR, PFS, and OS between the groups, but a trend of better RRs and longer survivals wasobserved in the NLR < 3.5 group than in the NLR≥3.5 group. Regarding adverse events, fatigue (grades 1−2) was observed in 8, hypothyroidism (grade 1–2) in 11, renal dysfunction (grade 1–3) in 6, loss of appetite (grade 1–2) in 2, pneumonitis (grade 3) in 1, rash (grade 1) in 2, and hypopituitarism (grade 3) in 1 patient(s). Conclusions: This retrospective study revealed the effectiveness and safety of nivolumab for MPM in the real-world setting.Nivolumab can be used as a standard second-line treatment for MPM. Furthermore, it has been suggested that the NLR may be a predictive marker of the effect of nivolumab for MPM, as pointed out in other carcinomas.

EphA2 inhibition suppresses proliferation of small-cell lung cancer cells through inducing cell cycle arrest

Small-cell lung cancer (SCLC) is characterized by one of neuroendocrine tumors, and is a clinically aggressive cancer due to its rapid growth, early dissemination, and rapid acquisition of multidrug resistance to chemotherapy. Moreover, the standard chemotherapeutic regimen in SCLC has not changed for three decades despite of the dramatic therapeutic improvement in non-SCLC. The development of a novel therapeutic strategy for SCLC has become a pressing issue. We found that expression of Eph receptor A2 (EphA2) is upregulated in three of 13 SCLC cell lines and five of 76 SCLC tumor samples. Genetic inhibition using siRNA of EphA2 significantly suppressed the cellular proliferation via induction of cell cycle arrest in SBC-5 cells. Furthermore, small molecule inhibitors of EphA2 (ALW-II-41-27 and dasatinib) also exclusively inhibited proliferation of EphA2-positive SCLC cells by the same mechanism. Collectively, EphA2 could be a promising candidate as a therapeutic target for SCLC.

A Phase II Study of Tailored-dose S-1 Plus Carboplatin Followed by Maintenance S-1 for Advanced Squamous Cell Lung Cancer: OSAKA-LCSG 1102

Objective A subset analysis of the LETS study suggested that S-1 plus carboplatin was more beneficial than paclitaxel plus carboplatin in terms of the overall survival (OS) in squamous cell lung cancer. However, the benefit of maintenance therapy for squamous cell non-small cell lung cancer (NSCLC) patients is still unknown. We herein report a phase II study to evaluate the efficacy and safety of a tailored dose of S-1 plus carboplatin followed by maintenance S-1 in chemotherapy-naive advanced squamous cell NSCLC. Methods Patients received carboplatin on day 1 plus S-1 on days 1 to 14 every 21 days. The dose of S-1 was determined by the body surface area and creatinine clearance. After four cycles of induction, non-progressive patients continued to receive S-1 until disease progression or unacceptable toxicity occurred. The primary endpoint was an objective response rate (RR) with a threshold value of 15%. The secondary endpoints were the progression-free survival (PFS) and OS from enrollment, the PFS in the maintenance phase, and safety. Results In the 33 patients analyzed, the rate of patients who met the primary endpoint was 30.3% (95% confidence interval: 15.6-48.7%), and the disease control rate was 75.8%. The median PFS and OS were 3.5 and 11.3 months, respectively. Ten patients received maintenance S-1, and the median PFS from the beginning of induction treatment was 5.3 months. Grade 3/4 toxicities with a frequency of more than 5% were all controllable. Conclusion Tailored-dose S-1 plus carboplatin followed by maintenance S-1 is an effective and feasible treatment for advanced squamous cell NSCLC.

Pembrolizumab-induced autoimmune encephalitis in a patient with advanced non-small cell lung cancer: A case report

Immune checkpoint inhibitors have markedly changed lung cancer treatment and improved overall survival. However, immune checkpoint inhibitors may be associated with various adverse events, including encephalitis, although this complication is rare. We herein describe the clinical characteristics of a case of immune checkpoint inhibitor-induced encephalitis and its management. A 51-year-old man with squamous non-small cell lung cancer was receiving pembrolizumab treatment when he suddenly displayed an altered level of consciousness. Cerebrospinal fluid examination revealed elevated lymphocyte count and autoimmune encephalitis was suspected. The patient was promptly started on steroids and his consciousness immediately improved. Pembrolizumab treatment was discontinued; however, stable disease was maintained. In conclusion, encephalitis is a rare but possibly fatal adverse event of immune checkpoint inhibitors, and prompt diagnosis and treatment are mandatory.

Immune checkpoint inhibitor re-challenge in patients with advanced non-small cell lung cancer

Background

Immune checkpoint inhibitors have dramatically changed lung cancer treatment, demonstrating an overall survival benefit. There are limited data about re-challenge in patients with non-small cell lung cancer. We attempted to address this question for re-challenge of immune checkpoint inhibitor in patients with advanced non-small cell lung cancer.

Methods

We retrospectively analyzed 11 patients with advanced non-small cell lung cancer treated with nivolumab and re-challenged with nivolumab/pemblorizumab at Kansai Medical University Hospital from December 2015 to December 2017.

Results

Three patients achieved PR and two patients were in SD. These patients were apt to be good responders to the initial treatment, to develop immune-related adverse events and to be immediately started on re-challenge with immune checkpoint inhibitor. The median PFS was 2.7 (range, 0.5–16.1) months. Five patients (45%) had mild to moderate immune-related adverse events.

Conclusion

Our study shows the effectiveness of re-challenge of immune checkpoint inhibitors in a subset of non-small cell lung cancer patients. Re-challenge might become one of treatment option for advanced non-small cell lung cancer.

Consideration of the concordance rate of 22C3 and 28-8 antibody in NSCLC and its relation to the effect of nivolumab

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Background: Anti-PD-1 antibodies (Abs) have improved survival significantly in patients (pts) with advanced non-small cell lung cancer (NSCLC). Depending on the extent of PD-L1 expression, these drugs have become the standard care of initial treatment and 2nd line therapy. However, PD-L1 expression has not yet been recognized as a robust biomarker. Currently, two Anti-PD-1 Abs (Nivolumab, Pembrolizumab) are commercially available in Japan, but have each diagnostic immunohistochemical (IHC) assays (22C3 and 28-8Ab), respectively. The concordance rate of these assays is not yet well understood and the effect of these agents in concordance and inconsistency cases are also unknown. Based on these background, we explored the concordance rate of 22C3 and 28-8 Ab and its relation with the effect of Nivolumab (Nivo). Methods: We investigated the concordance rate of 22C3 and 28-8 as well as treatment effect and response of 24 advanced NSCLC pts treated in Kansai Medical University Hospital from December 2015 and May 2017. All pts had been tumor biopsy for pathologically immunostained and received Nivo at least once. We compared the PD-L1 expression levels of two IHC assays with 22C3 and 28-8Ab measured in different laboratories independently. Results: Pts’ characteristics included adenocarcinoma in 12 pts, squamous cell carcinoma in 11, and others in 1 pts, respectively. In IHC reaction with 22C3Ab, 58.3% and 29.2% of pts expressed PD-L1 on ≥1% and ≥50% of tumor cells and with 28-8Ab, 37.5% and 16.7% of pts expressed PD-L1 on ≥1% and ≥50% of tumor cells, respectively. Of 24 cases, 1 case experienced CR, 5 cases PR. In CR case, expression level was dissociated at 50% with 22C3 and 5% with 28-8. In PR cases, 2 cases had high expression in both, and 2 cases had moderate expression in both assays. However, the remaining one was dissociated as moderate in 22C3 Ab and negative in 28-8. All PD pts expressed 0% with both of the two Abs. Conclusions: Although the number of cases is small, the concordance rate of the two Abs in advanced NSCLC cases is not necessarily high, but the agreement rate in response cases was likely to be high. As both 0% cases were ineffective, measuring with two Abs may be useful for forecasting invalid cases.

Interstitial Lung Disease Following Single-Agent Nanoparticle Albumin-Bound Paclitaxel Treatment in Patients with Advanced Non-Small Cell Lung Cancer

Interstitial lung disease (ILD) is a serious and potentially fatal adverse event in lung cancer therapy. Nanoparticle albumin-bound paclitaxel (nab-PTX) is a novel, solvent-free formulation of paclitaxel (PTX). Although the incidence of nab-PTX-induced ILD is not clear, it is generally considered that this formulation presents a similar risk of developing ILD as PTX. Here, we report 3 patients who developed severe ILD following treatment with nab-PTX. We draw attention to the risk of developing drug-induced ILD following nab-PTX treatment, and highlight that this novel formulation might therefore not be as safe as PTX with respect to the development of ILD.

Retrospective analysis of single-agent nab-paclitaxel in patients with platinum-resistant non-small cell lung cancer

A retrospective study was conducted to investigate the efficacy and toxicity of single-agent nab-paclitaxel in 67 patients with platinum-resistant non-small cell lung cancer in Kansai Medical University Hospital from August 2013 to December 2015. Overall, 25% of patients experienced disease progression, 48% exhibited a partial response, 27% had stable disease and 0% had a complete response. The median progression-free survival (PFS) time was 4.8 months and the median overall survival time was 18.2 months. There was no statistically significant difference in PFS between patients with non-squamous carcinoma and squamous carcinoma, or between second-line use and post-second-line use. The most common severe adverse event was neutropenia, followed by interstitial lung disease, infection and fatigue. The results revealed that single agent nab-paclitaxel was associated with an acceptable level of toxicity and a favorable response. This regimen has been developed recently, thus it has not been sufficiently evaluated its toxicity and efficacy. Additional studies to evaluate these parameters in non-small cell lung cancer are warranted.

New prognostic biomarkers and therapeutic effect of bevacizumab for patients with non-small-cell lung cancer

BACKGROUND

Several biomarkers have emerged as potential prognostic and predictive markers for non-small-cell lung cancer (NSCLC). Successful inhibition of angiogenesis with the antivascular endothelial growth factor antibody, bevacizumab, has improved the efficacy seen with standard cytotoxic therapy of NSCLC. However, despite such enhanced treatment strategies, the prognosis for patients with advanced NSCLC remains poor.

PATIENTS AND METHODS

We assessed potential biomarkers in 161 NSCLC patients and 42 control patients. Enzyme-linked immunosorbent assay methods were used to evaluate three biomarkers: platelet-derived microparticle (PDMP), high-mobility group box-1 (HMGB1), and plasminogen activator inhibitor-1 (PAI-1). We studied the effects of bevacizumab on the expression of these markers. We also analyzed the relationship of the newly designed risk factor (NDRF) to overall survival and disease-free survival. The NDRF classification of patients was determined from the levels of PDMP, HMGB1, and PAI-1. To determine the individual prognostic power of PDMP, HMGB1, and PAI-1, we evaluated associations between their levels and patient outcomes by Kaplan-Meier survival analysis in a derivation cohort.

RESULTS

PDMP, HMGB1, and PAI-1 levels were higher in NSCLC patients compared with control patients. Notably, the difference in PDMP levels exhibited the strongest statistical significance (p<0.001). Multivariate analysis showed that HMGB1 and PAI-1 levels were significantly correlated with PDMP levels. Patients who received standard chemotherapy with bevacizumab exhibited significantly reduced levels of all three markers compared with patients who received standard chemotherapy. NDRF3 status (high levels of all three markers) was significantly correlated with a poor prognosis (p<0.05 for overall survival and disease-free survival).

CONCLUSION

Our results demonstrate that abnormal levels of PDMP, HMGB1, and PAI-1 are related to each other in NSCLC. Moreover, our findings suggest that the vascular complications associated with these markers may contribute to a poor prognosis for NSCLC patients.

Benign metastasizing leiomyoma and 18-FDG-PET/CT: A case report and literature review

Pulmonary benign metastasizing leiomyoma (PBML) is a rare disease entity that usually occurs in females of reproductive age with a previous history of uterine myoma. It is typically characterized by multiple pulmonary tumors consisting of benign leiomyoma cells. In the present study, two cases of PBML are discussed. The patient in each case underwent 2-deoxy-2-(fluorine-18)-fluoro-D-glucose positron emission tomography/computed tomography (18-FDG-PET/CT) scans. One patient demonstrated a lack of 18-FDG uptake and a quiescent clinical course. However, the second patient exhibited a markedly high uptake of 18-FDG and aggressive cell proliferation. The two tumors revealed significant differences in metabolic behavior and in clinical course; however, they were similar with regard to cellular appearance. A review of previous studies concerning the findings of 18-FDG-PET/CT in published cases of PBML was also conducted and is presented here.

Immunohistochemical analysis of NANOG expression and epithelial-mesenchymal transition in pulmonary sarcomatoid carcinoma

Pulmonary sarcomatoid carcinomas (PSCs) are defined as a group of poorly differentiated non-small cell lung cancers that demonstrate sarcoma-like differentiation. The mechanism of mesenchymal differentiation in PSC is epithelial-mesenchymal transition (EMT). The expression of homeobox protein NANOG (NANOG), which regulates the pluripotency of embryonic stem cells, is associated with the EMT process. Therefore, the present study aimed to assess the expression level of NANOG and the status of the EMT process in PSC. The data of patients with PSC were retrospectively reviewed and immunohistochemical analyses were performed on patient samples to examine the expression of NANOG and EMT-associated proteins. The comparator group included randomly selected patients with matched clinicopathological characteristics who had pulmonary adenocarcinoma (PA). In the present study, 12 patients with PSC (4 females and 8 males) were enrolled; their median age was 65 years (range, 36-79 years), and the number of patients with stage IB, IIB, IIIA, IIIB and IV disease were 1, 1, 1, 1 and 8, respectively. The immunoreactive score (IRS) for E-cadherin was significantly lower in the PSC group compared with the PA group (P<0.0001), whereas the IRS for vimentin was significantly higher in the PSC group compared with the PA group (P<0.0001). However, the IRS for NANOG was significantly decreased in the PSC group compared with the PA group (P<0.0001), which suggests that NANOG does not serve an essential role in EMT in PSC. In addition, the overall survival of patients with PSC was significantly lower compared with that of patients with PA (median survival time, 7.0 vs. 35.6 months, respectively; P=0.0256). However, no significant difference was observed in the OS of patients who expressed low compared with high levels of NANOG (P=0.4416). In conclusion, it was clearly demonstrated that cytoplasmic NANOG expression was significantly lower in PSC compared with PA, and that the EMT process in PSC was accelerated, compared with that in PA.

Microparticles as Biomarkers of Blood Coagulation in Cancer

Cancer is associated with hypercoagulopathy and increased risk of thrombosis. This negatively influences patient morbidity and mortality. Cancer is also frequently complicated by the development of venous thromboembolism (VTE). Tumor-derived tissue factor (TF)-bearing microparticles (MPs) are associated with VTE events in malignancy. MPs are small membrane vesicles released from many different cell types by exocytic budding of the plasma membrane in response to cellular activation or apoptosis. MPs may also be involved in clinical diseases through expression of procoagulative phospholipids. The detection of TF-expressing MPs in cancer patients may be clinically useful. In lung and breast cancer patients, MPs induce metastasis and angiogenesis and may be indicators of vascular complications. Additionally, MPs in patients with various types of cancer possess adhesion proteins and bind target cells to promoting cancer progression or metastasis. Overexpression of TF by cancer cells is closely associated with tumor progression, and shedding of TF-expressing MPs by cancer cells correlates with the genetic status of cancer. Consequently, TF-expressing MPs represent important markers to consider in the prevention of and therapy for VTE complications in cancer patients.

Phase II study of pemetrexed and carboplatin plus bevacizumab, followed by maintenance pemetrexed and bevacizumab in Japanese patients with non-squamous non-small cell lung cancer

The present study evaluated the efficacy and safety of pemetrexed, carboplatin and bevacizumab, followed by maintenance pemetrexed and bevacizumab, in chemotherapy-naïve patients with stage IIIB/IV non-squamous non-small cell lung cancer (NSCLC). The patients were administered pemetrexed (500 mg/m²), carboplatin (area under the concentration-time curve, 6.0 mg/ml × min) and bevacizumab (15 mg/kg) intravenously every three weeks for up to six cycles. Patients who did not experience tumor progression remained on maintenance pemetrexed and bevacizumab until disease progression or unacceptable toxicity occurred. The primary endpoint was the overall response rate. Of the 26 patients enrolled between March 2010 and April 2011, three were excluded due to brain metastases, therefore the intention-to-treat (ITT) population consisted of 23 patients. The median age was 64 years (range, 40–74 years) and 15 patients were male. In total, six patients had a performance status of 0, and 20 had stage IV tumors. The response rate was 69.6% [95% confidence interval (CI), 47.1–86.8], the disease control rate was 100% and the time to response was 1.2 months (95% CI, 0.72–1.93). The median progression-free survival time was 8.6 months (95% CI, 5.9–10.9) and the median overall survival time was 18.6 months (95% CI, 12.9–24.8). There were no grade 3 or worse hemorrhagic events and the feasibility was modest. Overall, pemetrexed and carboplatin plus bevacizumab, followed by maintenance pemetrexed and bevacizumab, was effective and tolerable in the patients with non-squamous NSCLC, and the time to response was relatively short.

Efficacy of intraperitoneal and intravenous chemotherapy and left upper abdominal evisceration for advanced gastric cancer

BACKGROUND

The study was carried out to evaluate the efficacy of intraperitoneal (i.p.) and intravenous (i.v.) chemotherapy, as well as left upper abdominal evisceration (LUAE), for patients with advanced gastric cancer.

METHODS

We carried out a retrospective study of 348 patients who underwent gastrectomy for advanced gastric carcinoma between 1978 and 1998 at our institution and who had macroscopic type 3 or 4 cancer (Japanese classification) with depth of invasion to the serosal surface, but no liver metastasis or lymph node metastasis around the abdominal aorta. Cumulative survival rates were compared in patients who underwent gastrectomy together with: (1) intraoperative i.p. chemotherapy alone, (2) postoperative i.v. chemotherapy alone, (3) both i.p. and i.v., or (4) no chemotherapy. Then patients were stratified according to the presence of peritoneal dissemination (P+) and its absence (P-). In P+ patients, survival was compared between those who received i.v. chemotherapy and those who did not, and between those who received i.p. chemotherapy and those who did not. Then, survival was compared between patients with high and low immunosuppressive acidic protein (IAP) levels. Finally, we compared cumulative survival rates in patients (stratified as P+ and P-) who underwent LUAE with cumulative survival rates in those who underwent total gastrectomy combined with resection of the pancreatic body, tail, and spleen (PS).

RESULTS

For P- patients, there was no survival advantage with adjuvant i.p. or i.v. therapy when compared with surgery alone. For P+ patients, however, there was an improvement in survival when patients received both i.p. and i.v., compared with survival with surgery alone (P < 0.05). In P+ patients aged less than 60 years, there was improvement in survival for those who underwent i.p. therapy together with surgery (P < 0.05), but not for those who had i.v. chemotherapy after surgery. When LUAE was examined, there was a survival advantage for this procedure when there was no peritoneal dissemination. Four long-term survivors (surviving for more than 5 years) were identified in our study. Three of the 4 patients were aged less than 60 years, and all 4 had macroscopic type 4 gastric cancers.

CONCLUSION

Although the prognosis for patients with invasive type gastric cancer remains poor, there have been a few long-term survivors, in whom this survival was associated with aggressive combination therapy, including surgery, i.p., and i.v. therapy. P+ patients aged less than 60 years and patients with type 4 gastric cancer may stand to benefit most from such therapy. For P- patients, the role of adjuvant i.p. or i.v. therapy continues to be ambiguous, although LUAE in this population may be superior to PS.

Co-overexpression of DEAD box protein rck/p54 and c-myc protein in human colorectal adenomas and the relevance of their expression in cultured cell lines

The RCK gene was cloned through a study of the breakpoint of the t(11;14)(q23;q32) chromosomal translocation observed in a human B-cell lymphoma and overexpression of the protein (rck/p54) due to the translocation was shown to be associated with malignant transformation. The rck/p54 protein belongs to the DEAD box protein/RNA helicase family, which has a variety of functions such as translation initiation, pre-mRNA splicing and ribosome assembly. It is considered that rck/p54 protein may have significant effects on the mRNA structure of genes associated with cell proliferation, facilitating protein synthesis. Expression of rck/p54 in colorectal adenomas, which are a premalignant lesion of colorectal cancer, was examined by Western blot analysis and immunohistochemistry. The rck/p54 protein was found to be overexpressed in tumor tissues resected from 17 of 26 cases (65.4%) of colorectal adenomas and 13 of 14 c-myc-positive cases (92.8%) also co-overexpressed rck/p54 protein. Thus, a significant correlation between rck/p54 and c-myc co-overexpression was found (Spearman's rank correlation, P = 0.0018). We demonstrate that overexpression of rck/p54 in two different cell lines, COS 7 and human colorectal cancer cell line SW480, caused an increase in c-myc protein levels by enhancement of its translation efficiency and/or stabilization of its mRNA. These results suggest that rck/p54 of the DEAD box protein/RNA helicase family may contribute to cell proliferation and carcinogenesis in the development of human colorectal tumors at the translational level by increasing synthesis of c-myc protein.

Recurrent giant longitudinal duodenal ulcer with massive hemorrhage in a Helicobacter pylori-negative patient

A 67-year-old man, in whom a linear ulcer running from the duodenal bulb to the descending part had been noted 3 years previously, was admitted to our hospital because of abdominal pain and melena. Duodenoscopy revealed a bleeding giant longitudinal ulcer, which was more extensive than before. Tests for Helicobacter pylori (Hp) were negative. The ulcer was cured by endoscopic hemostasis and repeated blood transfusions. Attention must be paid to Hp-negative post-bulbar duodenal ulcers because of the frequent complications including hemorrhage.

Structural, CV and IR spectroscopic evidences for preorientation in PET-active phthalimido carboxylic acids

Hydrogen bond and potassium cation mediated preorientation were detected for phthalimido acetic acid and the corresponding acetate. Evidence for these phenomena came from X-ray structure analysis as well as cyclic voltammetric and IR spectroscopic measurements. These interactions rationalize the photoinduced electron transfer (PET) reactivity of the substrates in photodecarboxylation reactions.

[A case of stage IV gastric cancer with multiple liver metastases and carcinomatous ascites responding to TS-1 for six months before progression]

We report the case of a 72-year-old male with Stage IV gastric cancer accompanied by multiple liver metastases and carcinomatous ascites which responded to chemotherapy using TS-1. Treatment of the patient with daily oral administration of 120 mg TS-1 for 4 weeks resulted in complete regression of the liver metastases and ascites, as well as a 35% reduction in the size of the primary lesion. After 2 cycles, the primary tumor size was reduced to 55% and serum CA19-9 and CA125 levels were decreased to the normal ranges. This regimen was effective without any adverse effects, and improved the patient's QOL, for 6 months before progression of liver lesions. The patient received chemotherapy at our outpatient clinic for 10 months after the first treatment, after which he died of peritonitis carcinomatosa. The current case suggests that TS-1 may have a potent therapeutic efficacy in advanced gastric cancer patients.

Frequent altered expression of fragile histidine triad protein in human colorectal adenomas

Fragile histidine triad (FHIT) gene is involved in deletions on the short arm of chromosome 3 in various human cancers. We found that 47% of colorectal adenomas, which is a higher frequency than that of K-ras, showed altered expression of the Fhit protein by Western blot analysis. The amount of Fhit protein was inversely correlated with the degree of dysplasia. Importantly, 27% of low-grade dysplastic adenomas showed altered expression of Fhit protein. Additionally, expression of human Fhit protein in human colon carcinoma cell line SW480 exhibited a marked inhibition of growth and rendered SW480 cells highly susceptible to undergo apoptosis compared with control cells. These findings suggest that altered expression of the FHIT gene is a quite early aberration in the development of colorectal tumors and that Fhit protein may act as a tumor suppressor.

Impact of the expression of cyclin-dependent kinase inhibitor p27Kip1 and apoptosis in tumor cells on the overall survival of patients with non-early stage gastric carcinoma

BACKGROUND

The expression of p27Kip1 and apoptosis have been implicated in tumor aggressiveness and proved to be prognostic predictors for several human malignancies. In this study, the authors sought to investigate the expression of p27Kip1 and apoptosis and their potential significance in determining the prognosis of patients with non-early stage gastric carcinoma.

METHODS

Primary gastric tumor specimens from 225 patients were investigated by immunohistochemistry with anti-p27Kip1 and anti-Ki-67 antibodies, and their apoptotic indices were determined with the use of an Apop-Tag in situ detection kit.

RESULTS

The median p27Kip1 labeling index (LI) was 48.4%. There was a significant association between the p27 LIs and the apoptotic indices (Als). However, there was no association between the p27 LIs and the Ki-67 LIs. p27 LI was demonstrated to be one of the most significant and independent prognostic factors in multivariate analysis. Although AI was found to be prognostically significant in univariate analysis, it failed to retain an independent and significant value regarding overall survival in multivariate analysis.

CONCLUSIONS

Decreased expression of p27Kip1 and reduction of apoptotic potential were two of the most important factors in predicting a poor prognosis for patients with non-early stage gastric carcinoma. These findings support the hypothesis that decreased p27Kip1 expression, which may reflect a decreased rate of apoptosis, is closely related to the aggressiveness of gastric carcinoma. Therefore, the assessment of p27Kip1 expression and apoptotic potential may prove valuable in identifying patients with gastric carcinoma who are at high risk for recurrence and would benefit from adjuvant therapy.

Overexpression of rck/p54, a DEAD box protein, in human colorectal tumours

The RCK gene is a target of the t(11;14)(q23;q32) chromosomal translocation observed in human B-cell lymphoma, and the overexpression of its protein (rck/p54) by the translocation was shown to cause malignant transformation. The rck/p54 protein belongs to the DEAD box protein/RNA helicase family, which has a variety of functions such as translation initiation, pre-mRNA splicing and ribosome assembly. The expression of rck p54 in colorectal adenocarcinoma cells was examined by immunohistochemistry and Western blot analysis. The rck/p54 protein was found to be overexpressed in tumour tissues resected from 13 (50%) out of 26 cases of colorectal adenocarcinomas and two out of two (100%) cases of colonic severe dysplastic adenomas. In view of activities of rck/p54 determined in other tissue types, we suggest that rck/p54 may contribute to the cell proliferation and carcinogenesis at the translational level in the development of colorectal tumours.

Clinical evaluation of lymph node metastasis in gastric cancer defined by the fifth edition of the TNM classification in comparison with the Japanese system

BACKGROUND

This study compared the classification of lymph node metastasis according to the number of involved nodes based on the new tumour node metastasis (TNM) system (fifth edition) with the classification by the Japanese Research Society for Gastric Cancer from an anatomical perspective.

METHODS

The two classifications were related to long-term results in 1489 patients with gastric cancer who underwent gastrectomy with systematic extended lymphadenectomy.

RESULTS

Both classifications performed well as prognostic indicators (5-year survival rates: pathological (p) N0, 89 per cent; pN1, 66 per cent; pN2, 34 per cent; pN3, nil; and M1, 10 per cent by the TNM classification; n0, 89 per cent; n1, 63 per cent; n2, 46 per cent; n3, 20 per cent; and n4, 8 per cent by the Japanese classification). For regional lymph nodes, the TNM classification was a better index of the prognosis. Significant survival differences were observed among patients with M1 disease according to the number of involved lymph nodes (between one and six nodes, 48 per cent; seven to 15 nodes, 12 per cent; more than 15 nodes, 2 per cent), indicating that patients with distant metastatic lymph nodes (M1) should also be classified by the number of involved nodes. On the other hand, the Japanese classification has the added benefit of being a good indicator of the anatomical extent of lymphadenectomy.

CONCLUSION

The new TNM classification provided a better index of the prognosis of patients who underwent systematic lymph node dissection. However, both classifications have specific benefits in the surgical treatment of gastric cancer.

Serum human hepatocyte growth factor (hHGF) is elevated in patients with metastatic gastric carcinoma

BACKGROUND/AIMS

Hepatocyte growth factor (HGF) is a stromally derived protein growth factor that modulates epithelial cell proliferation and motility. HGF may therefore be involved in tumor progression.

METHODOLOGY

We measured the immunoreactive (ir)-HGF concentration in the sera of 56 patients with human gastric carcinoma, using an enzyme-linked immunosorbent assay and evaluated its association with clinical and histopathologic factors. Clinical stages were classified in accordance with The General Rules for TNM Classification (International Union Against Cancer).

RESULTS

The serum hHGF concentrations from patients with gastric carcinoma significantly increased with increasing pathologic tumor grades. Also, there were significantly higher concentrations in patients with nodal metastasis compared to patients without metastasis. The serum hHGF concentrations in patients with liver metastasis were significantly higher than in patients without liver metastasis.

CONCLUSIONS

These data show that the serum hHGF concentration is elevated in gastric carcinoma patients with liver and nodal metastasis. In multivariate analysis, the serum hHGF concentration was found to be the most important independent factor in predicting overall survival. Thus, the current results suggest that HGF may be important in the progression and metastasis of gastric carcinoma.

AML1(-/-) embryos do not express certain hematopoiesis-related gene transcripts including those of the PU.1 gene

The AML1 and PEBP2beta/CBFbeta genes encode the DNA-binding and non-binding subunits, respectively, of the heterodimeric transcription factor, PEBP2/CBF. Targeting each gene results in an almost identical phenotype, namely the complete lack of definitive hematopoiesis in the fetal liver on embryonic day 11.5 (E11.5). We examined and compared the expression levels of various hematopoiesis-related genes in wild type embryos and in embryos mutated for AML1 or PEBP2beta/CBFbeta. The RNAs were prepared from the yolk sacs of E9.5 embryos, from the aorta-gonad- mesonephros regions of E11.5 embryos and from the livers of E11.5 embryos and RT-PCR was performed to detect various gene transcripts. Transcripts were detected for most of the hematopoiesis-related genes that encode transcription factors, cytokines and cytokine receptors, even in tissues from homozygously targeted embryos. On the other hand, PU.1 transcripts were never detected in any tissue of AML1(-/-) or PEBP2beta/CBFbeta(-/-) embryos. In addition, transcripts for the Vav, flk-2/flt-3, M-CSF receptor, G-CSF receptor and c-Myb genes were not detected in certain tissues of the (-/-) embryos. The results suggest that the expression of a particular set of hematopoiesis-related genes is closely correlated with the PEBP2/CBF function.

Serum human hepatocyte growth factor (hHGF) is elevated in patients with metastatic gastric carcinoma

BACKGROUND/AIMS

Hepatocyte growth factor (HGF) is a stromally derived protein growth factor that modulates epithelial cell proliferation and motility. HGF may therefore be involved in tumor progression.

METHODOLOGY

We measured the immunoreactive (ir)-HGF concentration in the sera of 56 patients with human gastric carcinoma, using an enzyme-linked immunosorbent assay and evaluated its association with clinical and histopathologic factors. Clinical stages were classified in accordance with The General Rules for TNM Classification (International Union Against Cancer).

RESULTS

The serum hHGF concentrations from patients with gastric carcinoma significantly increased with increasing pathologic tumor grades. Also, there were significantly higher concentrations in patients with nodal metastasis compared to patients without metastasis. The serum hHGF concentrations in patients with liver metastasis were significantly higher than in patients without liver metastasis.

CONCLUSIONS

These data show that the serum hHGF concentration is elevated in gastric carcinoma patients with liver and nodal metastasis. In multivariate analysis, the serum hHGF concentration was found to be the most important independent factor in predicting overall survival. Thus, the current results suggest that HGF may be important in the progression and metastasis of gastric carcinoma.

Overexpression of AML1 renders a T hybridoma resistant to T cell receptor-mediated apoptosis

The AML1 gene, which encodes the DNA binding subunit of the heterodimeric transcription factor, PEBP2/CBF, is involved in several types of chromosomal translocations associated with human acute myeloid leukemia, and has been shown by gene targeting to be essential for the development of definitive hematopoiesis in the murine fetal liver. In addition, the gene is expressed abundantly in T lymphocytes and has been implicated in T cell specific gene expression. In the present study we examined the function of AML1 in T cell receptor (TCR)-mediated, Fas/Fas-ligand dependent apoptosis of a T hybridoma line, DO11.10. Several independent cell clones overexpressing the AML1 protein were isolated by transfecting AML1 cDNA into these cells. These clones possessed an increased level of PEBP2/CBF DNA binding activity and were found to be resistant to apoptosis induced by anti-CD3 antibody treatment. Northern blot analysis revealed that induction of the Fas-ligand transcript was markedly suppressed in the anti-CD3 treated clones. Instead, expression of IL-2 receptor alpha subunit (IL-2R alpha), which is a manifestation of proliferative TCR signaling, was induced. This was in contrast to the parental, anti-CD3 treated DO11.10 cells where induction of Fas-ligand but not of IL-2R alpha was observed. Resistance of the AML1 overexpressing cell clones to TCR-mediated apoptosis is most likely attributable to the lack of Fas-ligand induction, since simultaneous treatment with anti-CD3 and anti-Fas antibodies caused apoptosis of the clones. The overall results suggest that the AML1 protein may play a pivotal role in switching TCR signaling between apoptosis and cell proliferation in T lymphocytes.

[Immunohistochemical study on the progression of colorectal cancer--with respect to apoptotic index, expression of apoptosis-related gene products, and labeling index of proliferating cell nuclear antigen (PCNA)]

To clarify the biological changes in the development and progression of colorectal cancer, immunohistochemical examination was performed with a particular focus on the activity of apoptosis, the expression of apoptosis-related gene products and cell proliferation activity, assessed by the labeling index of proliferating cell nuclear antigen (PCNA). Seventy-six resected specimens of colorectal cancer were used to investigate the expression of apoptosis-related gene products, Bcl-2 protein and PCNA labeling index, as well as the apoptotic index using the TUNEL method. Seventy-five percent of 60 advanced cancer specimens was negative for Bcl-2 protein, and the proportion was higher than that in early cancer specimens. The apoptotic index (AI) in the advanced cancers was significantly higher than in the early stage of cancers. Meanwhile, the percentage of PCNA-positive cells for the advanced cancers was significantly higher than for early cancer. This study demonstrated a decrease in Bcl-2 protein expression, an increase in tumor cell apoptosis, and opposite an increase of cellular proliferation activity in the progression of colon cancer from early to the advanced stage of the disease.

The protooncogene product, PEBP2beta/CBFbeta, is mainly located in the cytoplasm and has an affinity with cytoskeletal structures

The Pebpb2/Cbfb gene encodes the non-DNA binding beta subunit of the heterodimeric transcription factor, PEBP2/CBF, and has been implicated in a subtype of human acute myeloid leukemia, as well as being indispensable for the development of definitive hematopoiesis in the murine fetal liver. By examining a subcellular localization of the PEBP2beta/CBFbeta protein in tissue culture cells, we could reveal an additional aspect of the protein other than to be a subunit of a transcription factor. Immunoblot and immunocytochemical staining showed that PEBP2beta/CBFbeta was mostly present in the cytoplasm. This PEBP2beta/CBFbeta was free from its DNA-binding partner, the alpha subunit of PEBP2/CBF, as judged by the electrophoretic mobility shift assays. Furthermore, a significant amount of PEBP2beta/CBFbeta was retained in the cytoskeleton preparation after detergent extraction of the cells and was found by double immunofluorescence to colocalize with the F-actin on stress fibers and the vinculin in membrane processes. Thus, the present study extends PEBP2beta/CBFbeta to be a cytoskeleton-affinitive as well as nuclear protein. The implications of these results are discussed.

[Correlations between cell proliferating activity and apoptosis in the colorectal cancer and apoptosis in the mucosa adjacent to colorectal cancer]

To investigate the growth and progression of colorectal cancer, cell production versus cell loss in colorectal cancer was examined using the proliferating cell nuclear antigen (PCNA) positivity rate and apoptotic index (AI). Cell loss was then examined using AI in the mucosa adjacent to colorectal cancer. The higher the PCNA positivity rate, the higher the apoptotic index in colorectal cancer. These results suggested that changes in cell production and cell loss may be closely correlated and play a role in the growth and progression of colorectal cancer. In patients with advanced colorectal cancer, the mucous composition of the adjacent mucosa was classified as sialomucin-predominant. Apoptosis at the proliferating zone in the mucosa adjacent to colorectal cancer (one or two glandular ducts) was also examined using the TUNEL method. This suggests that the mucosa adjacent to cancer is involved in apoptosis.

Differentiation dependent expression and distinct subcellular localization of the protooncogene product, PEBP2beta/CBFbeta, in muscle development

The Pebpb2/Cbfb gene encodes the non-DNA binding subunit of the heterodimeric transcription factor, PEBP2/CBF. To examine the expression of the PEBP2beta/CBFbeta protein in vivo, we carried out immunohistochemistry using the tissues from adult mice as well as embryos. Although PEBP2beta/CBFbeta was detected in various tissues to various degrees, interesting features of expression were observed in the skeletal myogenic cells. Here PEBP2beta/CBFbeta was found mainly to occur as cytoplasmic staining and the intensity of this staining increased depending on the differentiation stage of the cells. In the undifferentiated myoblasts PEBP2beta/CBFbeta was undetectable, whereas moderate levels of PEBP2beta/ CBFbeta were detected in the elongated and aligned myocytes. PEBP2beta/CBFbeta appeared to accumulate further when the cells fused to each other to become multinucleated myotubes. Once the muscle fibers were established, PEBP2beta/CBFbeta was relocated onto or around the Z-lines. PEBP2beta/CBFbeta was also detected in the cytoplasm of cardiac myocytes and in the smooth muscle cells of the digestive tract. In all the above, the skeletal myotubes were the only case that showed both nuclear and cytoplasmic staining of PEBP2beta/CBFbeta. Thus, we could show differentiation dependent pattern of PEBP2beta/CBFbeta expression in muscle development and establish PEBP2beta/CBFbeta to be a cytoplasmic as well as nuclear protein in vivo.