[Successful Resection Using a Posterior Approach of a Tailgut Cyst in the Retrorectal Space].

We present the case of a Tailgut cyst occurring in the retrorectal space that was curatively resected using a posterior approach. A 40-year-old man presented to the Kochi Health Sciences Center with the chief complaint of perineal incongruity. Pelvic magnetic resonance imaging revealed a multilocular cystic lesion in the retrorectal space, with high signal intensity on T2-weighted imaging. After diagnosing a Tailgut cyst, we performed resection of the tumor using a posterior approach. The lesion was removed en bloc with the coccyx. Histopathologically, the lesion was diagnosed as a non-malignant Tailgut cyst, and the surgical margin was negative. The patient is currently doing well without recurrence at 20 months.

Cumulative incidence of venous thromboembolism in patients with advanced cancer in prospective observational study.

Venous thromboembolism (VTE) is frequently observed in patients with advanced cancer. The objective of this prospective observational study was to estimate, based on intensive screening, using computed tomography, lower-extremity ultrasonography, and D-dimer testing, the prevalence of VTE in patients with advanced cancer. Patients with metastatic or locally advanced cancer without anticoagulant therapy, who were planning to receive chemotherapy during 4 weeks, were eligible. Evaluations of VTE were performed at pretreatment, 12 weeks, and 24 weeks after the start of chemotherapy. Primary endpoint was cumulative incidence of VTE for 24 weeks. Secondary endpoints included incidence of VTE (pretreatment, 12 weeks, and 24 weeks after the start of chemotherapy), VTE according to primary cancer site, symptomatic VTE, pulmonary thromboembolism (PE), and treatment of VTE. We enrolled 860 patients with a median age of 68 years, including 34% female and 71% lung cancer. Cumulative incidence of VTE for 24 weeks was 22.6% (95% confidence interval: 19.8%-25.5%) (194 of 860 patients). Incidence of VTE was 11.3% pretreatment, 16.8% 12 weeks, and 14.1% 24 weeks. Symptomatic VTE was observed in 4.0% and PE in 1.0% of patients. By multivariate analysis, sex, D-dimer level, and platelet count were independent risk factors of VTE for 24 weeks. This large prospective observational study showed that cumulative incidence of VTE was high in advanced cancer patients, mainly lung cancer. Although most patients showed asymptomatic VTE, intensive screening of VTE may be considered in advanced cancer patients, especially in women with high level of D-dimer and decreased platelet count (UMIN000015243).

Naturally Occurring Hair Growth Peptide: Water-Soluble Chicken Egg Yolk Peptides Stimulate Hair Growth Through Induction of Vascular Endothelial Growth Factor Production.

Alopecia is divided into two categories: androgenic alopecia and nonandrogenic alopecia. An androgen-dependent abnormality of biological functions causes alopecia in males, but the role of androgens is not yet elucidated in female pattern hair loss (FPHL). Modulation of androgenic activity is not effective in certain kinds of androgenic alopecia in females, as well as in cases of nonandrogenic alopecia in males and females. The hair growth drug, minoxidil, stimulates vascular endothelial growth factor (VEGF) production as well as vascularization and hair growth in females. Yet, because minoxidil has side effects with long-term use, a safe alternative hair growth agent is needed. Whereas hair develops after birth in mammalian species, hair mostly grows in a precocial bird, in the chicken, between hatching days 14 and 15. Therefore, we hypothesized that the chicken egg contains a key hair growth factor. In this study, we demonstrated that water-soluble peptides derived from the egg yolk stimulate VEGF production and human hair follicle dermal papilla cell growth. We also found that these peptides enhance murine hair growth and improve hair growth in FPHL. Finally, we characterized that water-soluble egg yolk peptides induce VEGF expression through insulin growth factor-1 receptor activation-induced hypoxia-inducible factor-1α transcription pathway. We have given the name "hair growth peptide (HGP)" to this water-soluble egg yolk peptide.

Immunohistochemical expression analysis of leucine-rich PPR-motif-containing protein (LRPPRC), a candidate colorectal cancer biomarker identified by shotgun proteomics using iTRAQ.

BACKGROUND: Colorectal cancer (CRC) is the fourth most frequent cause of cancer deaths in the world. Novel biomarkers for the diagnosis, prognosis, and treatment of CRC are required to improve the clinical strategy. METHODS: We applied shotgun proteomics using isobaric tags for relative and absolute quantitation (iTRAQ) to identify novel biomarkers of CRC, and then we detected leucine-rich PPR-motif-containing protein (LRPPRC) expression in 83 normal colorectal tissues and 133 CRC tissues by immunohistochemistry. RESULTS: A total of 570 proteins were identified using iTRAQ. We validated the expression of LRPPRC protein by immunohistochemical analysis of the 77 proteins that showed expression changes in the cancer tissues >1.5-fold the levels in the normal tissues. The expression levels of LRPPRC were significantly higher in CRC tissues than those in normal colorectal tissues, and the expression levels were related with tumor differentiation and especially high in moderately differentiated CRC tissues. CONCLUSION: We identified a novel, differentially expressed protein, LRPPRC, which has the potential to serve as a molecular target for diagnosis and/or prognosis of CRC.

Pseudo-Meigs' syndrome secondary to metachronous ovarian metastases from transverse colon cancer.

Pseudo-Meigs' syndrome associated with colorectal cancer is extremely rare. We report here a case of pseudo-Meigs' syndrome secondary to metachronous ovarian metastases from colon cancer. A 65-year-old female with a history of surgery for transverse colon cancer and peritoneal dissemination suffered from metachronous ovarian metastases during treatment with systemic chemotherapy. At first, neither ascites nor pleural effusion was observed, but she later complained of progressive abdominal distention and dyspnea caused by rapidly increasing ascites and pleural effusion and rapidly enlarging ovarian metastases. Abdominocenteses were repeated, and cytological examinations of the fluids were all negative for malignant cells. We suspected pseudo-Meigs' syndrome, and bilateral oophorectomies were performed after thorough informed consent. The patient's postoperative condition improved rapidly after surgery. We conclude that pseudo-Meigs' syndrome should be included in the differential diagnosis of massive or rapidly increasing ascites and pleural effusion associated with large or rapidly enlarging ovarian tumors.

Surgical Management in Patients with Gastrointestinal Stromal Tumors: A Single-Center Experience.

BACKGROUND: We have revisited prognostic outcomes and recurrence patterns in patients with gastrointestinal stromal tumors (GISTs) who underwent complete surgical resection at a single institution. PATIENTS AND METHODS: Patients who underwent curative surgical treatment were divided into two groups: those with high-risk GISTs (high-risk group) and those with very low-, low-, and intermediate-risk GISTs (lower-risk group). RESULTS: A total of 109 patients who underwent surgery as an initial treatment for GIST were studied. The overall 5- and 10-year survival rates after surgery were 90.3 and 71.1%, respectively. The 5-year survival rate in high-risk group patients was 88.1%, and their overall survival rate did not vary significantly from that of the lower-risk group (5-year survival rate, 91.3%). The recurrence rate in patients with high-risk GISTs gradually increased without reaching a plateau, with a cumulative rate of GIST recurrence of 26.4 and 48.9% at 5 and 10 years after surgical treatment, respectively. CONCLUSIONS: Our data suggest that the repeat surgical management in metastatic GIST is of clinical usefulness whatever the risk and improves survival.

Liver function assessment using 99mTc-GSA single-photon emission computed tomography (SPECT)/CT fusion imaging in hilar bile duct cancer: A retrospective study.

BACKGROUND: The objective of this study was to determine the utility of Tc-99m-diethylenetriamine-penta-acetic acid-galactosyl human serum albumin ((99m)Tc-GSA) single-photon emission computed tomography (SPECT)/CT fusion imaging for posthepatectomy remnant liver function assessment in hilar bile duct cancer patients. METHODS: Thirty hilar bile duct cancer patients who underwent major hepatectomy with extrahepatic bile duct resection were retrospectively analyzed. Indocyanine green plasma clearance rate (KICG) value and estimated KICG by (99m)Tc-GSA scintigraphy (KGSA) and volumetric and functional rates of future remnant liver by (99m)Tc-GSA SPECT/CT fusion imaging were used to evaluate preoperative whole liver function and posthepatectomy remnant liver function, respectively. Remnant (rem) KICG (= KICG × volumetric rate) and remKGSA (= KGSA × functional rate) were used to predict future remnant liver function; major hepatectomy was considered unsafe for values <0.05. The correlation of remKICG and remKGSA with posthepatectomy mortality and morbidity was determined. RESULTS: Although remKICG and remKGSA were not significantly different (median value: 0.071 vs 0.075), functional rates of future remnant liver were significantly higher than volumetric rates (median: 0.54 vs 0.46; P < .001). Hepatectomy was considered unsafe in 17% and 0% of patients using remKICG and remKGSA, respectively. Postoperative liver failure and mortality did not occur in the patients for whom hepatectomy was considered unsafe based on remKICG. remKGSA showed a stronger correlation with postoperative prothrombin time activity than remKICG. CONCLUSION: (99m)Tc-GSA SPECT/CT fusion imaging enables accurate assessment of future remnant liver function and suitability for hepatectomy in hilar bile duct cancer patients.

Neoadjuvant imatinib treatment and laparoscopic anus-preserving surgery for a large gastrointestinal stromal tumor of the rectum.

BACKGROUND: Resection of a gastrointestinal stromal tumor (GIST) of the rectum can be difficult because of the particular location in the pelvis, and a large rectal GIST often requires abdominoperineal resection. Recent reports demonstrate that neoadjuvant imatinib treatment improves surgical outcomes in patients with a rectal GIST, and there are only a few reports of the effectiveness of laparoscopic surgery for a rectal GIST. CASE PRESENTATION: A 46-year-old man was found to have a rectal GIST that measured 80 mm and was located on the anterior wall of the lower rectum. After 6 months treatment with imatinib, the tumor decreased in size to 37 mm, and laparoscopic low anterior resection was performed. The patient is currently alive without any evidence of recurrence 37 months after surgery. CONCLUSIONS: Neoadjuvant imatinib should be a treatment of choice for a large rectal GIST. When marked tumor shrinkage is achieved, laparoscopic surgery may be the preferred procedure.

Laparoscopic resection of adult colon duplication causing intussusception.

Gastrointestinal duplications are uncommon congenital malformations that can occur anywhere along the gastrointestinal tract. Most cases are recognized before the age of 2 years, and those encountered in adults are rare. We describe here a case of ascending colon duplication in a 20-year-old male that caused intussusception and was treated laparoscopically. Although computed tomography revealed a cystic mass filled with stool-like material, the preoperative diagnosis was a submucosal tumor of the ascending colon. We performed a laparoscopic right colectomy, and the postoperative pathological diagnosis was duplication of the ascending colon, both cystic and tubular components. We conclude that gastrointestinal duplications, although rare, should be considered in the differential diagnosis of all abdominal and submucosal cystic lesions and that laparoscopy is a preferred approach for the surgical treatment of gastrointestinal duplications.

Intramucosal Signet Ring Cell Gastric Cancer Diagnosed 15 Months after the Initial Endoscopic Examination.

The size and shape of intramucosal signet ring gastric cancer in this case remained endoscopically unchanged for 15 months. Laparoscopy-assisted distal gastrectomy was performed, and immunohistochemical analysis revealed Ki-67 and p53 mutations to be negative in this case. Signet ring gastric cancer has long been thought to confer a worse prognosis than other forms of gastric cancer; however, our case did not progress to advanced gastric cancer for 15 months.

SASS6 overexpression is associated with mitotic chromosomal abnormalities and a poor prognosis in patients with colorectal cancer.

Spindle assembly abnormal protein 6 homolog (SASS6) plays an important role in the regulation of centriole duplication. To date, the genetic alteration of SASS6 has not been reported in human cancers. In the present study, we examined whether SASS6 expression is abnormally regulated in colorectal cancers (CRCs). Increased SASS6 mRNA and protein expression levels were observed in 49 (60.5%) of the 81 primary CRCs and 11 (57.9%) of the 19 primary CRCs, respectively. Moreover, the upregulation of SASS6 mRNA expression was statistically significant (P=0.0410). Next, using DLD-1 colon cancer cells inducibly expressing SASS6, SASS6 overexpression was shown to induce centrosome amplification, mitotic abnormalities such as chromosomal misalignment and lagging chromosome, and chromosomal numerical changes. Furthermore, SASS6 overexpression was associated with anaphase bridge formation, a type of mitotic structural abnormality, in primary CRCs (P<0.01). SASS6 upregulation in colon cancer was also revealed in the Cancer Genome Atlas (TCGA) data and was shown to be an independent predictor of poor survival (multivariate analysis: hazard ratio, 2.805; 95% confidence interval, 1.244­7.512; P=0.0112). Finally, further analysis of the TCGA data demonstrated SASS6 upregulation in a modest manner in 8 of 11 cancer types other than colon cancer, and SASS6 upregulation was found to be associated with a poor survival outcome in patients with kidney renal cell carcinoma and lung adenocarcinoma. Our present findings revealed that the upregulation of SASS6 expression is involved in the pathogenesis of CRC and is associated with a poor prognosis among patients with colon cancer. They also suggest that SASS6 upregulation is a genetic abnormality relatively common in human cancer.

CD44-SLC1A2 fusion transcripts in primary colorectal cancer.

A CD44-SLC1A2 fusion has recently been discovered in a subset of primary gastric cancers, and an APIP-SLC1A2 fusion has been described in a colon cancer cell line (SNU-C1); however, whether such SLC1A2 fusions occur in primary colorectal cancer (CRC) and whether such fusions are specific for gastrointestinal cancers remain uncertain. In the present study, we examined 90 primary CRCs and 112 primary non-small cell lung cancers (NSCLCs) for CD44-SLC1A2 and APIP-SLC1A2 fusion transcripts using RT-PCR and subsequent sequencing analyses. Although the expression of both types of SLC1A2 fusion transcripts was not detected in any of the NSCLCs, the expression of CD44-SLC1A2, but not the APIP-SLC1A2 fusion transcript, was detected in one (1.1 %) CRC. The CD44-SLC1A2 fusion transcript was expressed in cancerous tissue but not in corresponding non-cancerous tissue, and the fusion occurred between exon 1 of CD44 and exon 2 of SLC1A2; it was expected that a slightly truncated but functional SLC1A2 protein would be produced under the CD44 promoter. A quantitative RT-PCR analysis revealed that SLC1A2 mRNA expression was upregulated in CRC containing SLC1A2 fusion transcripts, while it was downregulated in most other CRCs. The SLC1A2 fusion-positive carcinoma was located on the right-side of colon, was a mucinous adenocarcinoma, was immunohistochemically negative for MSH2 mismatch repair protein, and contained no APC or KRAS mutations. Together, these results suggest that the expression of SLC1A2 fusion transcripts is related to a subset of primary CRCs and may contribute to the elucidation of the characteristics of SLC1A2 fusion-positive CRCs in the future.

Long-term survival following pancreatectomy and s-1 chemotherapy for pancreatic acinar cell carcinoma with peritoneal dissemination: a case report and literature review.

Current case is the third report of S-1 chemotherapy against acinar cell carcinoma (ACC) of pancreas, and our patient has achieved the longest reported recurrence-free survival, longer than 6 years, despite the presence of disseminated nodules at laparotomy.A 77-year-old man presented with abdominal discomfort. Computed tomography showed a low-density tumor in the pancreas tail and the patient was referred for surgery. A 3-cm sized pancreatic tumor, with localized disseminated nodules, was detected on laparotomy. Distal pancreatectomy with concomitant resection of disseminated nodules was performed, and histopathological examination revealed an ACC. Oral S-1 chemotherapy was administered postsurgery, and the patient showed no sign of recurrence during 73 months of follow-up. This is the first report of long-term survivor of pancreatic ACC with peritoneal dissemination, following pancreatectomy and S-1 chemotherapy.Current case suggests a beneficial effect of S-1 chemotherapy in cases of ACC.

Epiploic gonadal vein as a new bypass route for extrahepatic portal venous obstruction: report of a case.

A 61-year-old man was referred to our hospital to treat extrahepatic portal venous obstruction. Endoscopic injection sclerotherapy (EIS) was performed for the esophageal varices; however, the patient returned with massive hematemesis from gastric varices 6 months after treatment. Although the varices were treated with EIS, gastric devascularization and splenectomy concomitant with shunt surgery were required to treat uncontrollable, frequent diarrhea and abdominal distension. Because the splenic vein, left gastric vein, left portal vein, and inferior vena cava were inadequate for anastomosis, an epiploic gonadal vein bypass was performed. The bypass graft remains patent 7 months after surgery, and the patient is in good health without any clinical symptoms. We describe a new bypass route for extrahepatic portal venous obstruction.

Rapid shrinkage of a pancreatic serous cystadenoma with cystic degeneration: report of a case.

We report a rare case of pancreatic serous cystadenoma, which shrank remarkably from 6 to 1.5 cm in diameter, with cystic degeneration, over a period of only 3 weeks. A 29-year-old woman who presented with epigastric pain and jaundice underwent computed tomography, which showed a 6-cm monolocular cystic tumor in the pancreatic head. Endoscopic retrograde cholangiopancreatography showed stenosis and deviation of the inferior part of the extrahepatic bile duct. We performed surgery 3 weeks later for suspected mucinous cystadenoma or macroscopic serous cystadenoma of the pancreas. At laparotomy, the tumor in the pancreatic head was found to have shrunk remarkably. We excised the tumor completely by performing the Whipple procedure. Macroscopically, the mass was a 1.5-cm monolocular cyst. Microscopically, the cystic tumor was composed of a thick fibrous wall with granulation tissue and hemorrhage. Although epithelial cells were not found inside the cystic wall, numerous grossly invisible microcysts with glycogen-containing epithelial cells were seen at its periphery. Based on these findings, the tumor was diagnosed as a serous cystadenoma with cystic degeneration.

Functional discrepancy between two liver lobes after hemilobe biliary drainage in patients with jaundice and bile duct cancer: an appraisal using (99m)Tc-GSA SPECT/CT fusion imaging.

PURPOSE: To determine the functional discrepancy between the two liver lobes using technetium 99m ((99m)Tc) diethylenetriamine-pentaacetic acid-galactosyl human serum albumin ( GSA diethylenetriamine-pentaacetic acid-galactosyl human serum albumin ) single photon emission computed tomography (SPECT)/computed tomography (CT) fusion imaging following preoperative biliary drainage and portal vein embolization ( PVE portal vein embolization ) in patients with jaundice who have bile duct cancer ( BDC bile duct cancer ). MATERIALS AND METHODS: This retrospective study was approved by the institutional review board, with waiver of informed consent. Preoperative (99m)Tc- GSA diethylenetriamine-pentaacetic acid-galactosyl human serum albumin SPECT/CT fusion images from 32 patients with extrahepatic BDC bile duct cancer were retrospectively reviewed. Patients were classified into four groups according to the extent of biliary drainage and presence of a preoperative right PVE portal vein embolization : right lobe drainage group (right drainage), bilateral lobe drainage group (bilateral drainage), left lobe drainage group (left drainage), and left lobe drainage with right PVE portal vein embolization group (left drainage with right PVE portal vein embolization ). Percentage volume and percentage function were measured in each lobe using fusion imaging. The ratio between percentage function and percentage volume (the function-to-volume ratio) was calculated for each lobe, and the results were compared among the four groups. Statistical analysis was performed with Wilcoxon signed-rank tests and Mann-Whitney U tests. RESULTS: The median values for the function-to-volume ratio in the right drainage, bilateral drainage, left drainage, and left drainage with right PVE portal vein embolization group were 1.12, 1.05, 1.02, and 0.81 in the right lobe; and 0.51, 0.88, 0.96, and 1.17 in the left lobe. Significant differences in the function-to-volume ratio were observed among the four groups (right drainage vs bilateral drainage vs left drainage vs left drainage with right PVE portal vein embolization ; with P < .002, P = .023, and P < .002 for the right lobe and P < .001, P = .023, and P < .002 for the left lobe). CONCLUSION: Hepatic lobar function significantly differs between the two lobes, depending on the extent of biliary drainage and the presence of portal vein embolization.

RSPO fusion transcripts in colorectal cancer in Japanese population.

R-spondin (RSPO) gene fusions have recently been discovered in a subset of human colorectal cancer (CRC) in the U.S. population; however, whether the fusion is recurrent in CRC arising in patients from the other demographic areas and whether it is specific for CRC remain uncertain. In this study, we examined 75 primary CRCs and 121 primary lung cancers in the Japanese population for EIF3E-RSPO2 and PTPRK-RSPO3 fusion transcripts using RT-PCR and subsequent sequencing analyses. Although the expression of EIF3E-RSPO2 and PTPRK-RSPO3 was not detected in any of the lung carcinomas, RSPO fusions were detected in three (4%) of the 75 CRCs. Two CRCs contained EIF3E-RSPO2 fusion transcripts, and another CRC contained PTPRK-RSPO3 fusion transcripts. Interestingly, in one of the two EIF3E-RSPO2 fusion-positive CRCs, a novel fusion variant form of EIF3E-RSPO2 was identified: exon 1 of EIF3E was connected to exon 2 of RSPO2 by a 351-bp insertion. A quantitative RT-PCR analysis revealed that RSPO mRNA expression was upregulated in the three CRCs containing RSPO fusion transcripts, while it was downregulated in nearly all of the other CRCs. An immunohistochemical analysis and a mutational analysis revealed that the RSPO fusion-containing CRC had a CDX2 cell lineage, was positive for mismatch repair protein expression, and had the wild-type APC allele. Finally, the forced expression of RSPO fusion proteins were shown to endow colorectal cells with an increased growth ability. These results suggest that the expression of RSPO fusion transcripts is related to a subset of CRCs arising in the Japanese population.

Endovascular pseudoaneurysm repair after distal pancreatectomy with celiac axis resection.

Erosive hemorrhage due to pseudoaneurysm is one of the most life-threatening complications after pancreatectomy. Here, we report an extremely rare case of rupture of a pseudoaneurysm of the common hepatic artery (CHA) stump that developed after distal pancreatectomy with en block celiac axis resection (DP-CAR), and was successfully treated through covered stent placement. The patient is a 66-year-old woman who underwent DP-CAR after adjuvant chemoradiotherapy for locally advanced pancreatic body cancer. She developed an intra-abdominal abscess around the remnant pancreas head 31 d after the surgery, and computed tomography (CT) showed an occluded portal vein due to the spreading inflammation around the abscess. Her general condition improved after CT-guided drainage of the abscess. However, 19 d later, she presented with melena, and CT showed a pseudoaneurysm arising from the CHA stump. Because the CHA had been resected during the DP-CAR, this artery could not be used as the access route for endovascular treatment, and instead, we placed a covered stent via the inferior pancreaticoduodenal artery originating from the superior mesenteric artery. After stent placement, cessation of bleeding and anterograde hepatic artery flow were confirmed, and the patient recovered well without any further complications. CT angiography at the 6-mo follow-up indicated the patency of the covered stent with sustained hepatic artery flow. To our knowledge, this is the first reported case of endovascular repair of a pseudoaneurysm that developed after DP-CAR.

Comparison of pancreatic acinar cell carcinoma and adenocarcinoma using multidetector-row computed tomography.

AIM: To distinguish acinar cell carcinoma (ACC) from pancreatic adenocarcinoma (AC) by comparing their computed tomography findings. METHODS: Patients with ACC and AC were identified on the basis of results obtained using surgically resected pancreatectomy specimens. The preoperative computer tomographic images of 6 acinar cell carcinoma patients and 67 pancreatic adenocarcinoma patients in 4 phases (non-contrast, arterial, portal venous, and delayed phase) were compared. The scan delay times were 40, 70, and 120 s for each contrast-enhanced phase. The visual pattern, tomographic attenuation value, and time attenuation curve were assessed and compared between AC and ACC cases using the χ² test, Wilcoxon signed-rank test, and Mann Whitney U test. RESULTS: The adenocarcinomas tended to be hypodense in all 4 phases. The acinar cell carcinomas also tended to be hypodense in the 3 contrast-enhanced phases, although their computed tomographic attenuation values were higher. Further, 5 of the 6 acinar cell carcinomas (83%) were isodense in the non-contrast phase. The time attenuation curve of the adenocarcinomas showed a gradual increase through the 4 phases, and all adenocarcinomas showed peak enhancement during the delayed phase. The time attenuation curve of the acinar cell carcinomas showed peak enhancement during the portal venous phase in 4 cases and during the arterial phase in 2 cases. None of the 6 acinar cell carcinomas showed peak enhancement during the delayed phase. CONCLUSION: The tumor density in the non-contrast phase and time attenuation curve pattern clearly differ between acinar cell carcinomas and adenocarcinomas, and multidetector-row computed tomography can thus distinguish these tumors.

Accumulated phosphatidylcholine (16:0/16:1) in human colorectal cancer; possible involvement of LPCAT4.

The identification of cancer biomarkers is critical for target-linked cancer therapy. The overall level of phosphatidylcholine (PC) is elevated in colorectal cancer (CRC). To investigate which species of PC is overexpressed in colorectal cancer, an imaging mass spectrometry was performed using a panel of non-neoplastic mucosal and CRC tissues. In the present study, we identified a novel biomarker, PC(16:0/16:1), in CRC using imaging mass spectrometry. Specifically, elevated levels of PC(16:0/16:1) expression were observed in the more advanced stage of CRC. Our data further showed that PC(16:0/16:1) was specifically localized in the cancer region when examined using imaging mass spectrometry. Notably, because the ratio of PC(16:0/16:1) to lyso-PC(16:0) was higher in CRC, we postulated that lyso-PC acyltransferase (LPCAT) activity is elevated in CRC. In an in vitro analysis, we showed that LPCAT4 is involved in the deregulation of PC(16:0/16:1) in CRC. In an immunohistochemical analysis, LPCAT4 was shown to be overexpressed in CRC. These data indicate the potential usefulness of PC(16:0/16:1) for the clinical diagnosis of CRC and implicate LPCAT4 in the elevated expression of PC(16:0/16:1) in CRC.