Search

Hepatocyte growth factor (HGF) is a well-known multifunctional growth factor, and evidence has accumulated indicating that the HGF/MET (HGF receptor) signaling axis is involved in the progression of cancer. Macrophage-stimulating protein (MSP) is also known as a growth factor which activates not only macrophages but also cancer cells and osteoclasts through the activation of the specific Receptor d’origine nantais (RON). Pro-HGF and pro-MSP lack biological activity and, therefore, require proteolytic activation for conversion to an active two-chain form by HGF activator (HGFA). Although, there are several studies on HGF/MET signaling with castration-resistant prostate cancer (CRPC) and bone metastasis, reports on plasma protein are rare. In addition, the MSP/RON signaling axis in PC is not well understood. Here, we analyzed associations between PC progression and plasma HGF and MSP levels. We tested plasma samples from 58 patients with PC: 36 with castration-resistant (CR) PC and 22 with pretreatment for PC as control. We used enzyme-linked immunosorbent assay (ELISA) kit to determine plasma levels of HGF, MSP and HGFA, and examined correlations with clinicopathological characteristics such as Gleason grade and bone metastasis. PCR was used to evaluate HGF and MSP-related molecules in PC cell lines. Plasma levels of HGF, MSP and HGFA in the CRPC group were higher than in the control group (HGF: P

To elucidate the mechanism of radiation-induced cancers, we analyzed the expression profiles of microRNAs extracted from formalin-fixed paraffin-embedded (FFPE) gastric cancer (GC) tissue samples from atomic bomb survivors.The expression levels of miR-21, miR-24, miR-34a, miR-106a, miR-143, and miR-145 were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR).The expression of microRNAs was measured by qRT-PCR in a Hiroshima University Hospital cohort comprising 32 patients in the high-dose-exposed group and 18 patients in the low-dose-exposed group who developed GC after the bombing. The GC cases showing high expression of miR-24, miR-143, and miR-145 were more frequently found in the high-dose-exposed group than in the low-dose-exposed group. We next performed qRT-PCR of miR-24, miR-143, and miR-145 in a cohort from the Hiroshima Red Cross Hospital and Atomic-Bomb Survivors Hospital comprising 122 patients in the high-dose-exposed group and 48 patients in the low-dose-exposed group who developed GC after the bombing. High expressions of miR-24 and miR-143 were more frequently found in the high-dose-exposed group than in the low-dose-exposed group. Multivariate analysis demonstrated that only high expression of miR-24 was an independent predictor for the exposure status.These results suggest that the measurement of miR-24 expression from FFPE samples is useful to identify radiation-associated GC.

Resistance to or relapse after androgen deprivation therapy (ADT) remains a significant problem in patients with prostate cancer. Several studies have hypothesized that the overexpression of MET and the activating signaling axis in prostate cancer cells are associated with castration-resistant prostate cancer (CRPC). On the other hand, the expression of human kallikrein 1-related peptidase (KLK) 4, which activates plasma HGF activator zymogen, in prostate cancer patients with bone metastasis or advanced stage has also been reported. In this study, we analyzed the expression and phosphorylation of MET along with KLK4 by immunohistochemistry in 62 formalin-fixed paraffin-embedded sections of prostate cancer collected by needle biopsy at our hospital between 2006 and 2011. As a result, the phosphorylation of MET was observed in 56% (35 of 62 cases) and positively correlated with worsening PSA relapse rate in a group of ADT-treated patients (P = 0.0445), suggesting significant correlation with CRPC. Overexpression of KLK4 was observed in patients with high T stage (P = 0.0001) and high Gleason score (P = 0.0146), and the expression was correlated with the phosphorylation of MET (P = 0.0002). Pathologically, strong MET phosphorylation observed in specific architectures in prostate cancer, such as cribriform structures, ill-defined glands or solid patterns, suggested the significance of MET activation in promoting the architectural formation of prostate cancer. In addition, high positivity rate (80%) of phospho-MET staining at high-grade prostatic intraepithelial neoplasia (HGPIN) may indicate the importance of the activating signaling axis in the carcinogenesis of prostate cancer.

One of the disadvantages of laparoscopic surgery is its decreased tactile feedback. Surgical experience compensates for the decline in the sense of touch due to an improved ability to process visual information. Stochastic resonance (SR) is known to improve tactile sensation. In this study, we sought to improve the tactile feedback in laparoscopic surgery using SR to safely perform laparoscopic surgery. Ten surgeons (nine males and one female, age: 30–44 years, median age: 34) with the experiences of >50 laparoscopic surgeries volunteered to participate in this study. We tested the hypothesis that low-level noise applied to the hand can enhance the tactile sensation during surgery. We performed this experiment under three hand conditions (bare-handed conditions, gloved conditions and using the laparoscopic instrument with gloved hands). A piezoelectric actuator that generates vibrations was attached on the radial side of the participant’s index finger or to the grip of the laparoscopic instrument. Fine-touch tests were performed using the Semmes–Weinstein test kit. Moreover, we planned laparoscopic suturing and knot-tying tasks in the dry box and using an animal model under controlled vibrations. In the touch tests using bare hands, gloved hands and the laparoscopic instrument, the mean correct ratio was significantly lower than that observed in the test with no vibrations. Moreover, the OSATS scores for the laparoscopic suturing and knot-tying tasks showed significantly better scores with vibrations. This technique has a potential to be a great help in establishing safer and high-quality laparoscopic procedures.

Colorectal cancer (CRC) is a leading cause of cancer mortality and the third most common cancer worldwide. Annually, there are more than 900,000 cases occur worldwide, nearly 500,000 of which are fatal. CRC have accumulated defects in oncogenes and tumor suppressor genes. Many CRCs likely arise through clonal outgrowth and evolution of an epithelial cell or cells in an adenomatous precursor lesion via so-called adenoma-carcinoma sequence. Intensive studies have uncovered that the spectra of these genetic modifications are highly variable across the tumors. While genetic changes in tumors of individual patients can be assessed in several stratified methods, these data still need to be properly interpreted for necessitating model systems for analysis of chemosensitivity of CRC patients, which could enable us to organically coordinate among genotype-to-phenotype correlations, clinicopathological features and clinical outcomes. One of the most plausible models for implementing this magnificent scheme is most likely to be “organoid”, which is a novel 3D intestinal stem cell culture system and has successfully reconstitute normal and cancerous colonic crypts in in vitro through using the specific niche factors in a dish, such as EGF, Wnt3a, Rspondin-1 and Noggin, together with a TGF-b inhibitor and a p38 inhibitor. Two groups, Van der Wetering et.al and Fujii et.al, have previously reported the establishment of organoid biobank of colorectal cancer patients, and both of them proved the usefulness of this platform for underpinning the significance of genotype-phenotype analysis in every single patient and providing insights into tailor-made therapy in CRC. In this present study, we generated a pairs of cancerous and normal adjacent organoids from a number of CRC patients and aimed to figure out sustainability and reproducibility of CRC organoids especially in terms of phenotypic and genotypic features even after several times of passage. We compared growth activity and histopathological features of the CRC organoids among several time points after the passage by evaluating ki-67 labeling index and morphology of the organoids. In order to confirm the stability of genetic status of representative cancer-related genes, we focused on TP53, KRAS, BRAF, and MSI status. We then tried to elucidate the difference of chemosensitivity between MSI-high and MSI-low/MSS CRC cases with similar genetic background in most of the representative cancer-related genes. Although further in-depth studies on CRC organoids are needed, our approach would be instrumental in accurately predicting the drug sensitivity of CRC patients, which could possibly lead to the establishment of personalized medicine in CRC. Citation Format: Naoya Sakamoto, Akira Ishikawa, Ririno Honma, Takao Hinoi, Naohide Oue, Kazuhiro Sentani, Shoichiro Mukai, Tomohiro Adachi, Hiroyuki Egi, Hideki Ohdan, Wataru Yasui. A colorectal cancer organoid library provides a promising screening tool for assessment of chemosensitivity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4836. doi:10.1158/1538-7445.AM2017-4836

A straightforward in vivo monitoring technique for biomolecules would be an advantageous approach for understanding their spatiotemporal dynamics in living cells. However, the lack of adequate probes has hampered the quantitative determination of the chemical composition and metabolomics of cellular lipids at single-cell resolution. Here, we describe a method for the rapid, direct, and quantitative determination of lipid molecules from living cells using single-cell Raman imaging. In vivo localization of lipids in the form of triacylglycerol (TAG) within oleaginous microalga and their molecular compositions are monitored with high spatial resolution in a nondestructive and label-free manner. This method can provide quantitative and real-time information on compositions, chain lengths, and degree of unsaturation of fatty acids in living cells for improving the cultivating parameters or for determining the harvest timing during large-scale cultivations for microalgal lipid accumulation toward biodiesel production. Therefore, this technique is a potential tool for in vivo lipidomics for understanding the dynamics of lipid metabolisms in various organisms.

We report an unusual case of small bowel obstruction due to an ursodeoxycholic acid (UDCA) enterolith that occurred 7 years after liver transplantation. A 70-year-old man had undergone multiple operations, including a living donor liver transplantation (LDLT) and hepaticojejunostomy. Four years after the LDLT, cholestasis developed, for which oral UDCA was administrated. Seven years after the LDLT, he was admitted to our hospital because of pneumonia; intestinal obstruction occurred following its resolution. A radiographic contrast study and computed tomographic scan indicated a movable mass as the cause of the ileus, suggesting a giant stone. We were unable to observe or remove the stone by double balloon enteroscopy owing to the presence of severe adhesion; thus, we surgically removed the mass. The patient's postoperative course was uneventful. He was discharged 20 days after the operation. An infrared spectrophotometric analysis revealed that the stone was a true enterolith, primarily composed of unconjugated UDCA. An ileus caused by a true enterolith is a rare clinical complication of LDLT. Nevertheless, it must be considered in the differential diagnosis of intestinal obstructions in liver transplant recipients with Roux-en-Y hepaticojejunostomies and/or bowel stasis.

Dutasteride, a dual 5α-reductase inhibitor, is used to treat benign prostatic hyperplasia (BPH). However, its histopathological effects on the morphometrics of blood vessels and glands are still controversial. This study aimed to assess the histopathological effects of dutasteride in cases of BPH in a retrospective manner.Patients with BPH were administered 0.5 mg of dutasteride daily or left untreated prior to undergoing holmium laser enucleation of the prostate (HoLEP). After HoLEP, remaining prostatic peripheral tissue at the bladder neck and the apex was resected. Each specimen was subjected to hematoxylin/eosin and immunohistochemical staining for CD31, and microvessel density (MVD) was analyzed.In the dutasteride-treated group (n=14), the mean duration of administration was 7.07±2.46 weeks. MVD was significantly lower at the bladder neck side in the dutasteride-treated group than in the control group (p=0.018).The present study, to our knowledge for the first time, assessed MVD by evaluating the bladder neck and apex sides of the remaining prostatic peripheral tissue after HoLEP, allowing evaluation of MVD in more detail without intraoperative damage of the peripheral tissue, such as through heat denaturation. Dutasteride reduces MVD in the bladder neck side of the prostate among patients with BPH and may lead to decreased risk of perioperative prostatic urethral bleeding.

Chemotherapy for advanced colorectal cancer has developed remarkably in recent years. However, medical practitioners are occasionally unwilling to initiate a standard multi-agent chemotherapy regimen for patients whose general condition is poor. We report the case of a patient with aggressively growing liver metastases and impending organ failure and symptoms who was successfully treated with the induction of anti-epidermal growth factor receptor( EGFR) antibody single- agent therapy. With the selection of some biomarkers, induction with anti-EGFR antibody single-agent therapy might be a beneficial therapeutic option for the treatment of colorectal cancer in patients with imminent organ failure and severe symptoms caused by local tumor progression.

Verrucous carcinoma is a rare subtype of penile verruciform squamous cell carcinoma. However, in past literature, the diagnosis of verrucous carcinoma has been confused with giant condylomas, and papillary and warty carcinomas due to the absence of critical criteria in pathological diagnosis. We experienced two cases of penile verruciform tumor occurring in a 48-year-old Japanese male and an 88-year-old Japanese male. We performed partial penectomy without lymph node dissection after biopsy. Although we initially detected small palpablelymph node swelling in the latter case, unnecessary lymph node dissection could be avoided by pathological diagnosis using preoperative biopsy. The resected specimens were diagnosed in accordance with the World Health Organization (WHO) classification and current pathological reviews. Histopathological findings and immunohistochemical appearance were compatible with a diagnosis of verrucous carcinoma.

The clinical picture of bladder pheochromocytoma is usually typical; however, the diagnosis is occasionally delayed because of the rarity of this neoplasm. We report a case of unsuspected bladder pheochromocytoma in which the patient had a hypertensive episode during transurethral resection. A 67-year-old male presented with the chief complaint of painless macrohematuria. Cystoscopy revealed a submucosal tumor on the right lateral wall of the bladder. The tumor was operated on transurethrally, followed by partial cystectomy. The pathological diagnosis was pheochromocytoma, primarily occurring in the bladder. Treatment of this lesion requires a high degree of clinical suspicion based on the patient’s symptom complex in order to enable adequate preparation prior to surgical manipulation.

The efficacy of acupuncture and moxibustion treatment was examined on eight female patients with refractory interstitial cystitis (IC) who had been treated conservatively with hydrodistension, intravesical instillation of dimethyl sulfoxide, or oral medication. These patients had received hydrodistension on an average of 2.3±1.8 times. Moxa needles were applied to Ciliao in bladder meridian 32 and Xialiao in bladder meridian 34, and electroacupuncture was performed on Zhongliao in bladder meridian 33 at 3 Hz for 20 min once a week. The bladder condition was assessed by the visual analogue scale (VAS) score, the O'Leary-Sant Interstitial Cystitis Symptom Index (ICSI), the Interstitial Cystitis Problem Index (ICPI), and the maximum voided volume (MVV). After 3 months, patients who showed a reduction of2 in their VAS score, reduction of30% of ICSI and ICPI, and increase of100 ml MVV were considered responders. There were three responders, and after repeated therapy to maintain these effects, they no longer required hydrodistension. Two responders had no recurrence for 48 months or more. Acupuncture and moxibustion resulted in improvement in 38% of the patients (3/8) with refractory IC, and repeated therapy maintained the therapeutic effects. This therapy is traditional and relatively noninvasive. Although its precise mechanism of action is unclear, this study suggests that acupuncture and moxibustion treatment may be a complementary and alternative therapeutic option for refractory IC.

Up-regulation of caveolin-1 (CAV1) is associated with aggressive prostate cancer. Among Caucasian and African-American patients, plasma CAV1 levels are elevated in patients with castration-resistant prostate cancer (CRPC), but not in those with hormone-sensitive prostate cancer (non-CRPC), which implies that CAV1 could be a therapeutic target for CRPC. Here, we evaluated associations between plasma CAV1 levels and these types of cancer in Japanese men, and CAV1 expression in PC3 (CRPC) and LNCaP (non-CRPC) cell lines.Plasma samples were obtained from 58 patients with prostate cancer: 36 with CRPC and 22 with non-CRPC. Enzyme-linked immuno sorbent assay (ELISA) kits were used to determine CAV1 plasma levels; qRT-PCR and western blots were used to evaluate the expression of CAV1 mRNA and protein in cell lines.Plasma CAV1 levels in patients with CRPC were greatly higher than in those with non-CRPC (1.46±1.37 ng/ml in CRPC; 0.56±0.32 ng/ml in non-CRPC, p0.004). Western blot and real-time qRT-PCR showed CAV1 protein and mRNA in PC3 cells to be significantly overexpressed compared to its expression in LNCaP cells (p0.0001).Our results showed a relationship between CAV1 expression and prostate cancer progression, and support the possibility of CAV1 as a therapeutic target for CRPC.

We retrospectively reviewed the treatment outcome of 12 renal cell carcinoma (RCC) patients with bone metastasis who had undergone targeted therapy along with a regimen of multimodal treatment. We performed metastatectomy following nephrectomy on patients with resectable foci. Patients with unresectable bone metastasis underwent radiation therapy. With the exception of two patients, zoledronic acid was also administered. As a result, the overall survival rates of 83.3% at 1 year and 72.9% at 2 years in our study compared favorably with reported cases. Patients with complete resection of solitary bone metastasis with or without extrabone lesions had favorable outcomes. As differences in the response of the targeted therapy can be observed between bone and extrabone metastases, control of bone metastasis may be a key factor for the prognosis of metastatic RCC patients.

To evaluate the relationship between the Caveolin-1 (CAV1) T29107A (rs7804372) polymorphism and the risk of prostate cancer among Japanese populations, and the associations between CAV1 polymorphisms and clinicopathological characteristics, including Gleason grade and prostate-specific antigen (PSA) grade.We recruited 134 patients with prostate cancer and 86 healthy controls matched for age and smoking status. The CAV1 T29107A polymorphism status was determined by polymerase chain reaction and restriction fragment-length polymorphism analysis.Genotype distributions (p=0.0045) and allelic frequencies (p=0.0018) differed between prostate cancer and control groups in terms of the CAV1 T29107A polymorphism (Pearson's χ(2) test). Logistic regression analysis of case and control outcomes showed an odds ratio of 0.35 (95% Condifence interval=0.13-0.91, p=0.033) between the TT and AA polymorphisms, indicating a reduced risk of prostate cancer to be associated with the AA polymorphism. Subset analysis revealed no significant associations between this polymorphism and clinicopathological characteristics of prostate cancer.The results of this study demonstrated a relationship between the CAV1 T29107A variant and risk of prostate cancer. This polymorphism thus, merits further investigation as a potential genomic marker for the early detection of prostate cancer. Our results support the hypothesis that the CAV1 T29107A (rs7804372) polymorphism may influence susceptibility to prostate cancer; however, prostate cancer progression was not associated with this polymorphism in a Japanese population.

Hepatocyte growth factor activator (HGFA) is a serine protease and a potent activator of prohepatocyte growth factor/scatter factor (pro-HGF/SF), a multifunctional growth factor that is critically involved in tissue morphogenesis, regeneration, and tumor progression. HGFA circulates as a zymogen (pro-HGFA) and is activated in response to tissue injury. Although thrombin is considered to be an activator of pro-HGFA, alternative pro-HGFA activation pathways in tumor microenvironments remain to be identified. In this study, we examined the effects of kallikrein 1-related peptidases (KLKs), a family of extracellular serine proteases, on the activation of pro-HGFA. Among the KLKs examined (KLK2, KLK3, KLK4 and KLK5), we identified KLK4 and KLK5 as novel activators of pro-HGFA. Using N-terminal sequencing, the cleavage site was identified as the normal processing site, Arg407-Ile408. The activation of pro-HGFA by KLK5 required a negatively charged substance such as dextran sulfate, whereas KLK4 could process pro-HGFA without dextran sulfate. KLK5 showed more efficient pro-HGFA processing than KLK4, and was expressed in 50% (13/25) of the tumor cell lines examined. HGFA processed by these KLKs efficiently activated pro-HGF/SF, and led to cellular scattering and invasion in vitro. The activities of both KLK4 and KLK5 were strongly inhibited by HGFA inhibitor type 1, an integral membrane Kunitz-type serine protease inhibitor that inhibits HGFA and other pro-HGF/SF-activating proteases. These data suggest that KLK4 and KLK5 mediate HGFA-induced activation of pro-HGF/SF within tumor tissue, which may thereafter trigger a series of events leading to tumor progression via the MET receptor.

Cell surface proteolysis is important for the generation of bioactive proteins mediating tumor progression. Recent studies suggest that the membrane-anchored cell surface proteinases matriptase and hepsin have significant roles in tumors. We analyzed the expression and clinical relevance of matriptase and hepsin, and their inhibitors hepatocyte growth factor activator inhibitor type 1 (HAI-1) and type 2 (HAI-2) in 66 cases of conventional renal cell carcinomas (RCC). The mRNA level was evaluated in paired samples from tumor and non-tumorous renal tissues by real-time reverse transcription-polymerase chain reaction. As matriptase and hepsin potently activate the proform of hepatocyte growth factor (HGF), the expression of HGF and its receptor, c-Met, was also analyzed. Although upregulation of matriptase was observed occasionally in RCC, the expression level was not associated with prognostic parameters. Hepsin was downregulated in RCC, particularly in early stage disease, but upregulated in advanced stages. There was a trend of higher hepsin expression in RCC with distant metastasis, and Kaplan-Meier survival curves showed that high hepsin expression was associated with reduced overall survival (P

Spheroid colony formation is a typically method to identify cancer stem cells (CSC). The growth of spherical colonies is considered indicative of self-renewal ability, and is consistent with a CSC phenotype. However, mechanism of spheroid formation remains unclear in gastric cancer (GC). In the present study, we analyzed spheroid formation associated genes in GC. Comprehensive gene expression profile of MKN-45 and MKN-74 GC cell lines that were grown as monolayers or spheroids was obtained by Affymetrix GeneChip, and we found several kinds of genes whose expression was up-regulated or down-regulated in cells that were grown as spheroids. Among these, 10 kinds of kinesin genes were up-regulated in both MKN-45 and MKN-74 cells that were grown as spheroids. Kinesins are categorized into 14 subfamilies and classified as mitotic kinesins, which are involved in cell division, and non-mitotic kinesins, which are principally involved in intracellular transport. In spheroids, mitotic kinesins were up-regulated. In the present study, we focused on KIFC1, because antibody against KIFC1 is available. qRT-PCR analysis revealed that up-regulation of KIFC1 in both MKN-45 and MKN-74 cells that were grown as spheroids. Immunohistochemical analysis of KIFC1 was performed in 20 GC cases. Expression of KIFC1 was up-regulated in GC tissues in comparison with corresponding non-neoplastic mucosa. These results suggest that KIFC1 plays an important role in gastric carcinogenesis and may be a therapeutic target of GC. Citation Format: Naohide Oue, Shoichiro Mukai, Trang Pham T.B., Kazuhiro Sentani, Reiko Ito, Wataru Yasui. Significance of KIFC1 in spheroid formation of gastric cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1413. doi:10.1158/1538-7445.AM2015-1413

Introduction Although more than 100 cases of hemangioma of the urinary bladder have been reported, capillary-type hemangiomas of the bladder are rare. Pyogenic granulomas, which are common tumor-like vascular lesions of the skin and oral mucous membranes, reveal histopathological findings similar to capillary-type hemangiomas and are differentiated from ordinary hemangiomas by clinical features and etiologic factors. Little is known regarding the occurrence of pyogenic granulomas in the urinary bladder. Case presentation We present the case of a 78-year-old Japanese man who had developed a hemangiomatous lesion in his bladder which led to acute clot retention. He had a recent history of chemotherapy for pancreatic cancer. A solitary pedunculated mass measuring 1.2 cm was observed in the bladder. Histopathological analysis of the resected mass revealed marked lobular capillary proliferation with surface erosions. Conclusion Cystoscopic and pathologic findings in addition to possible predisposing factors supported a diagnosis of pyogenic granuloma of the urinary bladder.

Lynch syndrome (LS) is a disorder caused by mismatch repair gene mutations, which have been recognized to be associated with an increased frequency of colorectal and extracolorectal tumors. However, it remains controversial as to whether total or segmental colectomy should be performed to treat colorectal cancer in patients with LS. A 58-year-old male underwent total colectomy with ileostomy for advanced transverse colon cancer. He was also found to have LS based on his characteristic family history and the findings of a preoperative examination, including a microsatellite instability analysis of past multiple metachronous cancers. The postoperative histological findings showed mucinous adenocarcinoma without lymph node metastasis, and the loss of the MSH2 protein expression was confirmed on an immunohistochemical examination. The present case provided important information on the clinical management of multiple developing metachronous colorectal cancers in patients with LS.

Background In stage IV colorectal cancer (CRC) with unresectable metastases, whether or not resection of the primary tumor should be indicated remains controversial. We aim to determine the impact of primary tumor resection on the survival of stage IV CRC patients with unresectable metastases. Methods We retrospectively investigated 103 CRC patients with stage IV colorectal cancer with metastases, treated at Hiroshima University Hospital between 2007 and 2013. Of these, those who had resectable primary tumor but unresectable metastases and received any chemotherapy were included in the study. We analyzed the overall survival (OS) and short-term outcomes between the patients who received up-front systemic chemotherapy (USC group) and those who received primary tumor resection followed by chemotherapy (PTR group). Results Of the 57 included patients, 15 underwent USC and 42 PTR. The median survival times were 13.4 and 23.9 months in the USC and PTR groups, respectively (P = 0.093), but multivariate analysis for the overall survival showed no significant difference between the two groups (hazard ratio, 1.30; 95% confidence interval (CI), 0.60 to 2.73, P = 0.495). In the USC group, the disease control rate of primary tumor was observed in 12 patients (80.0%), but emergency laparotomy was required for 1 patient. Morbidity in the PTR group was observed in 18 cases (42.9%). Conclusions The overall survival did not differ significantly between the USC and PTR groups. USC may help avoid unnecessary resection and consequently the high morbidity rate associated with primary tumor resection for stage IV CRC with unresectable metastases.