Satoru Yasukawa

Whole genome sequencing discriminates hepatocellular carcinoma with intrahepatic metastasis from multi-centric tumors.

BACKGROUND & AIMS Patients with hepatocellular carcinoma (HCC) have a high-risk of multi-centric (MC) tumor occurrence due to a strong carcinogenic background in the liver. In addition, they have a high risk of intrahepatic metastasis (IM). Liver tumors withIM or MC are profoundly different in their development and clinical outcome. However, clinically or pathologically discriminating between IM and MC can be challenging. This study investigated whether IM or MC could be diagnosed at the molecular level. METHODS We performed whole genome and RNA sequencing analyses of 49 tumors including two extra-hepatic metastases, and one nodule-in-nodule tumor from 23 HCC patients. RESULTS Sequencing-based molecular diagnosis using somatic single nucleotide variation information showed higher sensitivity compared to previous techniques due to the inclusion of a larger number of mutation events. This proved useful in cases, which showed inconsistent clinical diagnoses. In addition, whole genome sequencing offered advantages in profiling of other genetic alterations, such as structural variations, copy number alterations, and variant allele frequencies, and helped to confirm the IM/MCdiagnosis. Divergent alterations between IM tumors with sorafenib treatment, long time-intervals, or tumor-in-tumor nodules indicated high intra-tumor heterogeneity, evolution, and clonal switching of liver cancers. CONCLUSIONS It is important to analyze the differences between IM tumors, in addition to IM/MC diagnosis, before selecting a therapeutic strategy for multiple tumors in the liver. LAY SUMMARY Whole genome sequencing of multiple liver tumors enabled the accuratediagnosis ofmulti-centric occurrence and intrahepatic metastasis using somatic single nucleotide variation information. In addition, genetic discrepancies between tumors help us to understand the physical changes during recurrence and cancer spread.

Contrast-enhanced harmonic endoscopic ultrasonography for pancreatobiliary diseases.

The combination of second‐generation ultrasound contrast agents and an endoscopic ultrasonography (EUS) system with a broad‐band transducer has allowed contrast‐enhanced harmonic imaging in the field of EUS. In contrast‐enhanced harmonic EUS (CH‐EUS), diffuse homogeneous enhancement is obtained in normal parenchyma of the pancreas. The bile duct and pancreatic duct are depicted as non‐enhanced ductal structures with strong contrast in comparison to the surrounding parenchyma. CH‐EUS identifies pancreatic adenocarcinomas as solid lesions exhibiting hypo‐enhancement with a sensitivity and specificity of 88–96% and 88–94%, respectively. In particular, 80–100% of false‐negative cases in endoscopic ultrasound‐guided fine‐needle aspiration (EUS‐FNA) are correctly classified by CH‐EUS, suggesting CH‐EUS complements EUS‐FNA. Moreover, CH‐EUS improves depiction of some subtle lesions in conventional EUS, thus facilitating EUS‐FNA. For quantitative perfusion analysis, a time–intensity curve (TIC) for the region of interest can be generated during CH‐EUS. The maximum intensity gain and the echo intensity reduction rate from the peak at 1 min obtained by TIC can be used for differentiation of pancreatic adenocarcinoma from other tumors. CH‐EUS is also useful for differentiation of invasive intraductal papillary mucinous neoplasms (IPMN) from non‐invasive IPMN, identification of malignant lesions in the gallbladder, and T‐ and N‐staging of pancreatobiliary tumors.

Intratumoral heterogeneity of MIB-1 labelling index in gastric gastrointestinal stromal tumor (GIST)

BackgroundThe MIB-1 labelling index (LI) is used as a prognostic indicator for gastrointestinal stromal tumors (GISTs). However, whether a biopsy-based LI represents the entire tumor is uncertain, because the LI is not always homogeneous. In this study, we examined the extent and characteristics of LI heterogeneity in gastric GISTs.MethodsWe analyzed ten c-kit-positive gastric GISTs with diameters exceeding 3 cm, of which six were multilobular and four were unilobular. For MIB-1-immunostained sections, continuous digital images were obtained through the maximum diameter of the lobules. We obtained LIs for images by carrying out computer-assisted image analysis, and calculated the means and standard deviations (SDs) of the LIs for the lobules. For each lobule, intralobular heterogeneity was evaluated on the basis of the SD. For multilobular tumors, interlobular heterogeneity was assessed on the basis of the mean LI difference between lobules.ResultsThe SDs, which ranged from 0.8% to 9.8%, indicated intralobular heterogeneity. Moreover, considerable interlobular heterogeneity was noted in five (83%) of the six multilobular GISTs, in which the maximum interlobular mean LI difference ranged from 9.6% to 27.2%. Notably, although the high maximum mean LI (14.1%–32.3%) showed that these five GISTs were high-grade tumors, they also contained at least one lobule showing a low-grade mean LI value (2.7%–5.1%).ConclusionGastric GISTs often show intralobular or interlobular MIB-1 LI heterogeneity. In multilobular GISTs, multiple biopsy samples may be required for the accurate evaluation of tumor grade.

Prognostic impact of the width of subserosal invasion in gastric cancer invading the subserosal layer

BACKGROUND The depth of wall invasion is one of the most important prognostic factors in patients with gastric cancers. We hypothesized that the horizontal width of spread of the neoplasm in the subserosal layer correlated with frequency of latent tumor exposure to the subserosal surface in subserosal (ss) gastric cancer. METHODS We compared retrospectively the relationship between the horizontal width of ss invasion and other clinicopathologic factors in 124 patients with ss cancer confirmed carefully to have T2 and not T3 neoplasms. Selected clinicopathologic parameters of these ss patients were compared to 134 patients with serosal penetration (se) by gastric cancer, and 78 patients with invasion of the muscularis propria only (mp). RESULTS The width of ss invasion was found to be an important prognostic factor on both univariate (P < .001) and multivariate analyses (P = .006). The prognosis of ss-cancer with narrow-width invasion (less than 20 mm) was similar to that of mp-cancer, while the prognosis of ss-cancer with wide width (more than 20 mm) was similar to that of se-cancer. CONCLUSION Our findings showed that narrow-width ss-cancer (<20 mm) behaved very similar to mp-cancers, while wide ss-cancers (> or =20 mm) behaved very similar to se-cancers. These findings demonstrated the prognostic impact of the width of cancer invasion in subserosal layer in patients with ss-cancer. Intensive chemotherapy and close follow-up should be recommended for ss-cancer patients with greater than 20 mm involvement of the subserosal layer.

A new histological classification for intra-operative histological examination of the ductal resection margin in cholangiocarcinoma.

The purpose of this study was to establish a standard histological classification for intra‐operative histological examination of ductal resection margins in cholangiocarcinoma to distinguish between epithelial and intramural lesions and to clarify correlations between the new classification and clinical outcomes. Intra‐operative diagnosis of ductal margins was performed for 357 stumps from 216 patients undergoing surgical resection of cholangiocarcinoma at the National Cancer Center, Japan. Three expert pathologists reviewed the materials and established a histological classification defined by grade of atypia. The new classification comprised four categories: ‘insufficient’, insufficient for diagnosis due to distortion of specimen; ‘negative for malignancy’, no atypia suggestive of neoplasia; ‘undetermined lesion’, specimen showing either cellular or structural atypia; and ‘positive for malignancy’, specimen showing both cellular and structural atypia. Each category was defined to distinguish between epithelial and intramural lesions. Validity and reproducibility of the proposed classification were found to be moderate to substantial. Multivariate analyses using the clinicopathological factors identified to be associated with overall survival by univariate analyses indicated that patients diagnosed with ‘positive for malignancy’ in intramural lesions of the proximal margin displayed significant poor prognosis. Meanwhile, in patients diagnosed with ‘positive for malignancy’ or ‘undetermined lesion’ in epithelial lesions of the proximal margin, no difference in overall survival was apparent compared to patients diagnosed with ‘negative for malignancy’. We propose new histological classification for intra‐operative histological examination of ductal resection margins in cholangiocarcinoma that shows a correlation with patients’ prognosis and should facilitate the determination of ductal resection margin status for cholangiocarcinoma. (Cancer Sci 2009; 100: 255–260)

Myoid hamartoma of the breast that proved difficult to diagnose: a case report

Myoid hamartomas of the breast are extremely rare breast lesions, with a poorly understood pathogenesis. We describe the case of a 38-year-old premenopausal woman who presenting with a mass in the left breast. Mammography revealed an oval mass that was partly indistinct, and ultrasonography showed a hypoechoic mass with a slightly irregular margin. Bilateral breast dynamic magnetic resonance imaging was performed for a more detailed evaluation. The images showed rapid initial enhancement and a microlobulated margin. Because the suspicion of malignancy was strong at that time, core needle biopsy was performed. Histologically, the tumor was identified as fibroadenoma. A case of myoid hamartoma of the breast that proved difficult to diagnose is reported, and discussed with reference to the literature.

Double cancer of the cystic duct and gallbladder associated with low junction of the cystic duct

We report a case of double cancer of the cystic duct and gallbladder associated with low junction of the cystic duct. A 73-year-old woman was admitted to the hospital complaining of upper abdominal pain. Endoscopic retrograde cholangiography showed a stenotic lesion in the lower common bile duct and no visualization of the cystic duct or gallbladder. Enhanced computed tomography revealed a heterogeneously enhanced tumorous lesion around the lower bile duct in the pancreatic head. A diagnosis of cancer arising from the cystic duct that entered the lower part of the common hepatic duct was made by intraductal ultrasonography, which showed an intraluminal protruding lesion in the cystic duct. Isolated gallbladder cancer was also diagnosed, by abdominal computed tomography. She underwent pancreaticoduodenectomy with dissection of regional lymph nodes. Histological examination revealed moderately differentiated adenocarcinoma of the cystic duct and well-differentiated adenocarcinoma of the gallbladder. Double cancer of the cystic duct and gallbladder is extremely rare, and this case also suggests a relationship between a low junction of the cystic duct and neoplasm in the biliary tract.

Detection of fusion gene in cell-free DNA of a gastric synovial sarcoma

Synovial sarcoma (SS) is genetically characterized by chromosomal translocation, which generates SYT-SSX fusion transcripts. Although SS can occur in any body part, primary gastric SS is substantially rare. Here we describe a detection of the fusion gene sequence of gastric SS in plasma cell-free DNA (cfDNA). A gastric submucosal tumor was detected in the stomach of a 27-year-old woman and diagnosed as SS. Candidate intronic primers were designed to detect the intronic fusion breakpoint and this fusion sequence was confirmed in intron 10 of SYT and intron 5 of SSX2 by genomic polymerase chain reaction (PCR) and direct sequencing. A locked nucleic acid (LNA) probe specific to the fusion sequence was designed for detecting the fusion sequence in plasma and the fusion sequence was detected in preoperative plasma cfDNA, while not detected in postoperative plasma cfDNA. This technique will be useful for monitoring translocation-derived diseases such as SS.

miR-509-5p and miR-1243 increase the sensitivity to gemcitabine by inhibiting epithelial-mesenchymal transition in pancreatic cancer

The epithelial-mesenchymal transition (EMT) contributes to various processes in cancer progression, such as metastasis and drug resistance. Since we have already established a cell-based reporter system for identifying EMT-suppressive microRNAs (miRNAs) in the pancreatic cancer cell line Panc1, we performed a function-based screening assay by combining this reporter system and a miRNA library composed of 1,090 miRNAs. As a result, we identified miR-509-5p and miR-1243 as EMT-suppressive miRNAs, although the mechanisms for EMT-suppression induced by these miRNAs have yet to be clarified. Herein, we demonstrated that overexpression of miR-509-5p and miR-1243 increased the expression of E-cadherin through the suppression of EMT-related gene expression and that drug sensitivity increased with a combination of each of these miRNAs and gemcitabine. Moreover, miR-509-5p was associated with worse overall survival in patients with pancreatic cancer and was identified as an independently selected predictor of mortality. Our findings suggest that miR-509-5p and miR-1243 might be novel chemotherapeutic targets and serve as biomarkers in pancreatic cancer.

Primary osteosarcoma of the uterine corpus: A case report

Pure osteosarcoma arising from the uterus is extremely rare. Only 15 cases of this type of cancer have been reported to date. Most patients showed local or lung metastasis early after surgery and died within a year of treatment initiation, regardless of multimodality therapy, indicating that this tumor is aggressive with a poor prognosis. Herein, we report the first clinical experience treated with a combination of docetaxel and gemcitabine for local and lung metastasis from primary osteosarcoma of the uterus. Although the disease was considered stable after three cycles of treatment, new metastatic lesions appeared in the lungs after six cycles. The patient was asymptomatic for 13 months; however, she died two months after symptom recurrence. Our case demonstrates that a combined regimen of docetaxel and gemcitabine may be a sound therapeutic option to control primary osteosarcoma of the uterus.