Japanese Society for Cancer of the Colon and Rectum (JSCCR) Guidelines 2016 for the Clinical Practice of Hereditary Colorectal Cancer (Translated Version)

Hereditary colorectal cancer accounts for less than 5% of all colorectal cancer cases. Some of the unique characteristics that are commonly encountered in cases of hereditary colorectal cancer include early age at onset, synchronous/metachronous occurrence of the cancer, and association with multiple cancers in other organs, necessitating different management from sporadic colorectal cancer. While the diagnosis of familial adenomatous polyposis might be easy because usually 100 or more adenomas that develop in the colonic mucosa are in this condition, Lynch syndrome, which is the most commonly associated disease with hereditary colorectal cancer, is often missed in daily medical practice because of its relatively poorly defined clinical characteristics. In addition, the disease concept and diagnostic criteria for Lynch syndrome, which was once called hereditary non-polyposis colorectal cancer, have changed over time with continual research, thereby possibly creating confusion in clinical practice. Under these circumstances, the JSCCR Guideline Committee has developed the "JSCCR Guidelines 2016 for the Clinical Practice of Hereditary Colorectal Cancer (HCRC)," to allow delivery of appropriate medical care in daily practice to patients with familial adenomatous polyposis, Lynch syndrome, or other related diseases. The JSCCR Guidelines 2016 for HCRC were prepared by consensus reached among members of the JSCCR Guideline Committee, based on a careful review of the evidence retrieved from literature searches, and considering the medical health insurance system and actual clinical practice settings in Japan. Herein, we present the English version of the JSCCR Guidelines 2016 for HCRC.

Automated histological classification of whole-slide images of gastric biopsy specimens

BACKGROUND

Automated image analysis has been developed currently in the field of surgical pathology. The aim of the present study was to evaluate the classification accuracy of the e-Pathologist image analysis software.

METHODS

A total of 3062 gastric biopsy specimens were consecutively obtained and stained. The specimen slides were anonymized and digitized. At least two experienced gastrointestinal pathologists evaluated each slide for pathological diagnosis. We compared the three-tier (positive for carcinoma or suspicion of carcinoma; caution for adenoma or suspicion of a neoplastic lesion; or negative for a neoplastic lesion) or two-tier (negative or non-negative) classification results of human pathologists and of the e-Pathologist.

RESULTS

Of 3062 cases, 33.4% showed an abnormal finding. For the three-tier classification, the overall concordance rate was 55.6% (1702/3062). The kappa coefficient was 0.28 (95% CI, 0.26-0.30; fair agreement). For the negative biopsy specimens, the concordance rate was 90.6% (1033/1140), but for the positive biopsy specimens, the concordance rate was less than 50%. For the two-tier classification, the sensitivity, specificity, positive predictive value, and negative predictive value were 89.5% (95% CI, 87.5-91.4%), 50.7% (95% CI, 48.5-52.9%), 47.7% (95% CI, 45.4-49.9%), and 90.6% (95% CI, 88.8-92.2%), respectively.

CONCLUSIONS

Although there are limitations and requirements for applying automated histopathological classification of gastric biopsy specimens in the clinical setting, the results of the present study are promising.

Expression of B7-H3 (CD276) in surgically resected esophageal squamous cell carcinoma

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Background: B7-H3 (also known as CD276) belongs to a family of immune modulators that includes PD-1 and PD-L1 (also known as B7-H1 or CD274), which has been reported to be expressed in many carcinomas and associated with poor prognosis. In this study, we explored the relationship between B7-H3 expression and clinical background and prognosis of esophageal squamous cell carcinoma (ESCC) patients treated with surgery alone. Methods: The subjects of this study was the ESCC patients who received curative surgery between January 2009 and December 2014 without prior treatment, excluding T4 and M1 disease. We evaluated tumor B7-H3 expression by immunohistochemistry, which was scored to 0 (absent) if < 10% of cancer cells were stained, and 1 (weak), 2 (moderate), or 3 (strong) according to the intensity in stained cancer cells (> 10%). The B7-H3 expression of score 2 and 3 was regarded as positive. We compared the clinical characteristics and prognosis between B7-H3 positive and negative patients using log rank test and Cox proportional hazards regression analysis for adjusting the backgrounds. Results: 33 (45%) of 74 patients were positive for expression of B7-H3. Between H7-H3 (+) and (-) groups, there were difference in pathological T stage (pT1/pT2/pT3: 9/0/24 vs. 23/4/14, p < 0.01) and lymph vessel invasion (+/-: 7/26 vs. 17/24, p=0.08). There was no association between sex, age, N factor, and vascular invasion. B7-H3 (+) patients showed trend of poor recurrence free survival (RFS) and overall survival, not significant, (HR=1.41[95%CI:0.63-3.14] p=0.41 for RFS, HR=1.34[ 95%CI:0.52-3.48] p=0.55 for OS). However B7-H3 status was not a prognostic factor in multivariate analysis (HR=0.78[95% CI: 0.33-1.85] for RFS, HR=0.73 [ 95%CI:0.26-2.02] for OS). Conclusions: The expression ratio of B7-H3 was observed in 45% of the esophageal cancer, which was related with T stage and lymphatic vessel invasion but not with clinical outcomes such as RFS and OS.

Predictive relevance of lymphovascular invasion in T1 colorectal cancer before endoscopic treatment

BACKGROUND AND AIM

 The depth of tumor invasion is currently the only reliable predictive risk factor for lymph node metastasis before endoscopic treatment for colorectal cancer. However, the most important factor to predict lymph node metastasis has been suggested to be lymphovascular invasion rather than the depth of invasion. Thus, the aim of this study was to investigate the predictive relevance of lymphovascular invasion before endoscopic treatment.

METHODS

 The data on pT1 colorectal cancers that were resected endoscopically or surgically from 2007 to 2015 were retrospectively reviewed. The cases were categorized into two groups: positive or negative for lymphovascular invasion. The following factors were evaluated by univariate and multivariate analyses: age and sex of the patients; location, size, and morphology of the lesion; and depth of invasion.

RESULTS

 The positive and negative groups included 229 and 457 cases, respectively. Younger age ( P  < 0.01), smaller lesion size ( P  = 0.01), non-LST (LST: laterally spreading tumor) ( P  < 0.01), presence of depression ( P  < 0.01), and pT1b ( P  < 0.01) were associated with lymphovascular invasion. In multivariate analysis, younger age (comparing patients aged ≤ 64 years with those aged > 65 years, OR, 1.81; 95 %CI, 1.29 - 2.53), presence of depression (OR, 1.97; CI, 1.40 - 2.77), non-LST features (OR, 1.50; CI, 1.04 - 2.15), and pT1b (OR, 3.08; CI, 1.91 - 4.97) were associated with lymphovascular invasion.

CONCLUSION

 Younger age, presence of depression, T1b, and non-LST are associated with lymphovascular invasion. Therefore, careful pathological diagnosis and surveillance are necessary for lesions demonstrating any of these four factors.

Disentangling the prognostic heterogeneity of stage III colorectal cancer through histologic stromal categorization

BACKGROUND

Growing evidence suggests the importance of stroma in determining cancer biology and recent studies have identified that genes closely associated with poor prognosis subtypes of colorectal cancer are expressed by the stroma rather than epithelial cancer cells. We aimed to clarify the prognostic value of the novel histologic classification of desmoplastic reaction in stage III colorectal cancer.

METHODS

A pathologic review was conducted for 466 stage III colorectal cancer patients in a single Japanese institution (1999-2006). Desmoplastic reaction was classified as mature, intermediate, or immature according to existence of hyalinized collagen bundles and myxoid stroma, both appear exclusively at the desmoplastic front. An additional 432 patients treated at four independent institutions (2007-2008) were examined as a second cohort to validate the results.

RESULTS

According to desmoplastic reaction, 164, 133, and 169 patients were classified as mature, intermediate, and immature, respectively. Five-year relapse-free survival rates were highest in the mature group (86.0%), followed by the intermediate (73.7%) and immature (50.9%) groups. An adverse prognostic impact of desmoplastic reaction was invariably observed in stage IIIB, which contained 71% of stage III cases. Harrell's concordance index for relapse-free survival was greater in desmoplastic reaction (0.66) than any conventional tumor-associated prognostic factors including tumor node metastasis substage (0.62) and tumor grade (0.53). Similar results were observed in the second cohort, wherein desmoplastic reaction categorization was the most influential prognostic factor.

CONCLUSION

Histologic desmoplastic reaction categorization could be a key to solve the issue of prognostic heterogeneity in stage III colorectal cancer, thereby enhancing the value of tumor node metastasis stage.

SOX10 Expression as Well as BRAF and GNAQ/11 Mutations Distinguish Pigmented Ciliary Epithelium Neoplasms From Uveal Melanomas

Purpose

Adenocarcinomas or adenomas derived from pigmented ciliary epithelium (APCE) are exceptionally rare ocular tumors. These tumors have pigmented and epithelioid features, and some APCEs are negative for keratin markers and positive for melanocytic markers. It is especially difficult to distinguish APCEs from uveal melanoma (UM). Accordingly, we examined protein expression and genetic mutations associated with APCE to facilitate diagnosis.

Methods

Five APCE and 11 UM samples were obtained from patients during surgical resection at our institute. APCE and UM ocular structures were compared comprehensively. Protein expression and genetic alterations involved in malignant melanoma were evaluated.

Results

SOX10 was expressed diffusely in all 11 UMs and in surrounding uveal or choroidal melanocytes, but not in the APCEs or nontumorous pigmented epithelia. Additionally, the expression patterns of cytokeratins and melanocytic markers differed between UMs and APCEs. We identified BRAF V600E mutations in four of five APCE samples, but not in the 11 UM samples. Moreover, GNAQ or GNA11 mutations were found in 10 of the 11 UM samples, but not in APCE samples. NRAS mutations were not observed in either tumor group examined.

Conclusions

APCE is a separate entity distinguished from UM by the absence of SOX10 expression and presence of the BRAF V600E mutation. These results have implications for diagnosis, providing a means to distinguish between UM and APCE.

Automated histological classification of whole slide images of colorectal biopsy specimens

Background

An automated image analysis system, e-Pathologist, was developed to improve the quality of colorectal biopsy diagnostics in routine pathology practice.

Objective

The aim of the study was to evaluate the classification accuracy of the e-Pathologist image analysis software in the setting of routine pathology practice in two institutions.

Materials and methods

In total, 1328 colorectal tissue specimens were consecutively obtained from two hospitals (1077 tissues from Tokyo hospital, and 251 tissues from East hospital) and the stained specimen slides were anonymized and digitized. At least two experienced gastrointestinal pathologists evaluated each slide for pathological diagnosis. We compared the 3-tier classification results (carcinoma or suspicion of carcinoma, adenoma, and lastly negative for a neoplastic lesion) between the human pathologists and that of e-Pathologist.

Results

For the Tokyo hospital specimens, all carcinoma tissues were correctly classified (n=112), and 9.9% (80/810) of the adenoma tissues were incorrectly classified as negative. For the East hospital specimens, 0 out of the 51 adenoma tissues were incorrectly classified as negative while 9.3% (11/118) of the carcinoma tissues were incorrectly classified as either adenoma, or negative. For the Tokyo and East hospital datasets, the undetected rate of carcinoma, undetected rate of adenoma, and over-detected proportion were 0% and 9.3%, 9.9% and 0%, and 36.1% and 27.1%, respectively.

Conclusions

This image analysis system requires some improvements; however, it has the potential to assist pathologists in quality improvement of routine pathological practice in the not too distant future.

WNT Pathway Gene Mutations Are Associated With the Presence of Dysplasia in Colorectal Sessile Serrated Adenoma/Polyps

Sessile serrated adenoma/polyps (SSA/Ps) are believed to be the major precursor of serrated pathway-derived colorectal carcinomas. To better characterize the process of progression from SSA/Ps to carcinomas, we analyzed 46 SSA/Ps with dysplasia and 45 SSA/Ps without dysplasia using targeted next-generation sequencing and immunohistochemistry. Among the WNT pathway genes analyzed, protein-truncating mutations of RNF43, APC, and ZNRF3 were identified in 23 (50%), 4 (9%), and 3 (7%) SSA/Ps with dysplasia, respectively. In contrast, SSA/Ps without dysplasia rarely had WNT pathway gene mutations, except for 3 lesions with RNF43 mutations (7%). None of the SSA/Ps had CTNNB1 mutations or RSPO fusions. Thus, WNT pathway gene mutations were more common in SSA/Ps with dysplasia than in SSA/Ps without dysplasia (P=3.0×10). Consistently, nuclear β-catenin accumulation and MYC overexpression, indicative of active WNT signaling, were present in most of the SSA/Ps with dysplasia, but were rare in those without dysplasia. BRAF (86%) or KRAS mutations (7%) were identified in the majority of SSA/Ps, regardless of the presence or absence of dysplasia. MLH1 expression was lost in 14 SSA/Ps with dysplasia (30%). The majority of MLH1-deficient SSA/Ps with dysplasia had RNF43 mutations (86%), most of which were frameshift mutations involving mononucleotide repeats. In contrast, MLH1-retained lesions had less frequent RNF43 mutations with no hot spots (34%), and 4 had APC mutations (13%). These results suggest that WNT pathway gene mutations are involved in the development of dysplasia in SSA/Ps and that MLH1-deficient and MLH1-retained SSA/Ps with dysplasia exhibit distinct mutation profiles of WNT pathway genes.

Tumor location is a risk factor for lymph node metastasis in superficial Barrett's adenocarcinoma

BACKGROUND AND STUDY AIMS

Endoscopic treatment is indicated for superficial Barrett's adenocarcinoma (BA) with a negligible risk of lymph node metastasis (LNM). However, risk factors associated with LNM in superficial BA are still not well characterized. The aim of the current study was to clarify risk factors for LNM of superficial BA.

PATIENTS AND METHODS

A retrospective study was conducted in 87 consecutive patients with BA that was resected at National Cancer Center Hospital, Tokyo, Japan between 1990 and 2013. We assessed tumor size, macroscopic type, histological type, tumor depth of invasion, lymphovascular invasion and tumor location to analyze factors associated with LNM. Tumor location was classified into following 2 groups according to Siewert classification: 1) BA of the esophagogastric junction (EGJ-BA) as those having their center within 1 cm proximal from the EGJ; and 2) Esophageal-BA as those having their center at 1 cm or more proximal to the EGJ. EGJ was defined as distal end of the palisade vessels.

RESULTS

 LNM was detected in 10 (11 %) patients. Univariable analysis revealed that tumor size, tumor depth of invasion, histological type of mixed differentiated and undifferentiated-type adenocarcinoma, lymphovascular invasion and tumor location of esophageal-BA were significantly associated with LNM. Multivariable analysis revealed that tumor location of esophageal-BA [odds ratio 7.8 (95 %CI: 1.3 - 48.1)] was a potential risk factor for LNM.

CONCLUSIONS

The current study demonstrated that tumor location is a potential risk factor for LNM in BA. Therefore, indications for endoscopic treatment of esophageal-BA and EGJ-BA could be different.

Intramucosal colorectal carcinoma with invasion of the lamina propria: a study by the Japanese Society for Cancer of the Colon and Rectum

Cancer invasion of the lamina propria is an important pathological finding. However, the clinicopathologic features and diagnostic accuracy of intramucosal carcinoma assessment in colorectal carcinoma (CRC) are unknown. In this study, intramucosal CRCs were reviewed in institutions affiliated with the Japanese Society for Cancer of the Colon and Rectum, and 32 cases with invasion of the lamina propria were identified. Next, a consensus meeting was held to select cases with a high consensus about the presence of invasion, which were reviewed by one Western pathologist for confirmation. In addition to clinicopathologic evaluation, concordance was assessed for diagnosis and histologic findings. During the consensus meeting, 3 cases were found to show ambiguous features such that it was unclear whether there was intramucosal or submucosal invasion, and 7 cases were judged to have invasion of the lamina propria by more than 75% of the pathologists. A poorly differentiated adenocarcinoma and a signet ring cell carcinoma were diagnosed unanimously. Concordance in diagnosis and detection of characteristics of invasion of the lamina propria proved to be only poor to fair. Single or small clusters of cells and atypical or complex glandular arrangements that are beyond normal mucosal architecture were detected more frequently in the 7 high-consensus tumors. Desmoplasia and marked inflammation were detected more often in cases characterized as ambiguous. Intramucosal CRCs with invasion of the lamina propria constituted 5.1% of the surgically resected high-grade intramucosal epithelial dysplastic/neoplastic lesions, and stromal infiltration of single or small clusters of cells is the best objective criterion of invasion.

Comprehensive characterization of RSPO fusions in colorectal traditional serrated adenomas

AIMS

Traditional serrated adenoma (TSA) is a rare but distinct type of colorectal polyp. Our previous study showed that PTPRK-RSPO3 fusions are frequent and characteristic genetic alterations in TSAs. This study aimed to characterize comprehensively the prevalence and variability of RSPO fusions in colorectal TSAs.

METHODS AND RESULTS

We examined RSPO expression and explored novel RSPO fusions in 129 TSAs, including 66 lesions analysed previously for WNT pathway gene mutations. Quantitative polymerase chain reaction (qPCR) analyses identified three and 43 TSAs overexpressing RSPO2 and RSPO3, respectively, whereas the expression of RSPO1 and RSPO4 was marginal or undetectable in all cases. RSPO overexpression was always mutually exclusive with other WNT pathway gene mutations. Known PTPRK-RSPO3 fusions were detected in 37 TSAs, all but one of which overexpressed RSPO3. In addition, rapid amplification of cDNA ends revealed three novel RSPO fusion transcripts, an NRIP1-RSPO2 fusion and two PTPRK-RSPO3 fusion isoforms, in six TSAs. Overall, 43 TSAs had RSPO fusions (33%), whereas four TSAs (3%) overexpressed RSPO in the absence of RSPO fusions. TSAs with RSPO fusions showed several clinicopathological features, including distal localization (P = 0.0063), larger size (P = 0.0055), prominent ectopic crypt foci (P = 8.4 × 10^-4 ), association of a high-grade component (P = 1.1 × 10^-4 ), and the presence of KRAS mutations (P = 4.5 × 10^-5 ).

CONCLUSIONS

The present study identified RSPO fusion transcripts, including three novel transcripts, in one-third of colorectal TSAs and showed that PTPRK-RSPO3 fusions were the predominant cause of RSPO overexpression in colorectal TSA.

Clinical outcomes and prognostic factors in gastric cancer patients aged ≥85 years undergoing endoscopic submucosal dissection

BACKGROUND AND AIMS

Although the number of gastric cancer patients aged ≥85 years indicated for endoscopic submucosal dissection (ESD) has increased, little is known about the outcomes and prognostic factors. This study aimed to investigate the clinical outcomes and prognostic factors for overall survival (OS) of patients aged ≥85 years who underwent ESD for gastric cancer.

METHODS

We retrospectively reviewed 108 patients aged ≥85 years with 149 gastric cancers treated by ESD between 1999 and 2014 at our institution. The clinical outcomes and prognosis were evaluated. Furthermore, the relationships between patient and lesion characteristics with OS were determined using the Kaplan-Meier method and a Cox proportional hazards model.

RESULTS

All patients had Eastern Cooperative Oncology Group performance status (PS) of 0 to 1. En bloc, R0, and curative resections were achieved in 98.0%, 91.3%, and 72.7%, respectively, without severe adverse events requiring surgery. During a median follow-up period of 40.2 months (range, 1.8-108.7 months), 23 patients died, including 2 of gastric cancer. The 3-year (54.3% vs 95.9%) and 5-year (54.3% vs 76.3%) OS rates were significantly lower in patients with a low (<44.6) as opposed to a higher (≥44.6) prognostic nutritional index (PNI) (P < .001). The PNI was independently prognostic of OS (hazard ratio, 7.0; 95% confidence interval, 2.2-22.9; P = .001).

CONCLUSIONS

ESD is feasible for gastric cancer patients aged ≥85 years with good PS. However, low PNI was found to be prognostic of reduced OS, indicating the need to evaluate the PNI in determining whether to perform ESD.

Clinical outcomes of gastric polyps and neoplasms in patients with familial adenomatous polyposis

Background and study aims Familial adenomatous polyposis (FAP) is an autosomal dominant syndrome caused by a germline mutation in the adenomatous polyposis coli (APC) gene, characterized by the presence of more than 100 adenomatous polyps in the colorectum. The upper gastrointestinal tract is an extracolonic site for malignancy in patients with FAP. The frequency of death in Japanese patients with FAP because of gastric cancer is 2.8 % and that because of colon cancer is 60.6 %. Few studies have reported upper gastrointestinal diseases in patients with FAP. In the present study, we investigated the clinical outcomes of patients with FAP diagnosed with gastric neoplasms. Patients and methods We enrolled 80 patients with FAP who underwent esophagogastroduodenoscopy from October 1997 to December 2011. We investigated patient characteristics, endoscopic findings of gastric lesions, treatment outcomes, and long-term courses. Results Fundic gland polyposis was observed in 51 patients (64 %) and gastric neoplasms in 22 patients (28 %), including 20 with non-invasive and 2 with invasive neoplasm. Of the 26 neoplasms, 11 were treated by endoscopic resection (ER) and 4 by surgical resection. Metachronous gastric neoplasms were observed in 7 patients (15 lesions) and treated by ER, except for in 1 patient. No patients died of gastric lesions during a median follow-up period of 6.5 years (range, 0 - 14). Conclusion Because gastric lesions including gastric cancers in patients with FAP did not cause any deaths, they can be considered to have favorable prognoses. Early detection of gastric neoplasms through an appropriate follow-up interval may have contributed to these good outcomes.

Long-term clinical outcomes of endoscopic submucosal dissection for colorectal neoplasms in 423 cases: a retrospective study

Background and study aim Endoscopic submucosal dissection (ESD) is known as a curative treatment for colorectal superficial neoplasms. There is however a need for more long-term clinical data to establish the full advantages of colorectal ESD regarding very low recurrence rates. The aim of this retrospective study was to determine long-term clinical outcomes of colorectal ESD. Methods A total of 423 lesions treated by ESD for colorectal adenoma/dysplasia or adenocarcinoma between 1998 and 2008 at a single high volume referral center were included. We conducted a retrospective survey on patients with follow-up and obtained complete 1-, 3-, and 5-year outcome data for 358 (85 %), 292 (69 %), and 209 (49 %) lesions, respectively. Curative resection was defined when the pathological specimen had carcinoma-free resection margins, irrespective of piecemeal or en bloc resection, without submucosal deep invasion (≥ 1000 µm), lymphovascular involvement, or a poorly differentiated adenocarcinoma component. Results After a median 4.9 years of follow-up, the 3-year overall cumulative endoscopic recurrence rate and cancerous recurrence rate were 2.9 % (95 % confidence interval [95 %CI] 1.2 - 4.7) and 1.1 % (0 - 2.1), respectively. The 5-year overall cumulative endoscopic recurrence and cancerous recurrence rates were 3.8 % (1.7 - 5.9) and 1.6 % (0.1 - 3.0), respectively. In 361 lesions eligible for endoscopic follow-up, the 3-year endoscopic recurrence and cancerous recurrence rates were 2.4 % (0.8 - 4.1) and 0.4 % (0 - 1.4), respectively. Multivariate analysis revealed that piecemeal resection and submucosal deep tumor invasion were associated with recurrence. Conclusions The current study demonstrated favorable long-term clinical outcomes of colorectal ESD when en bloc curative resection is achieved.

Germline PMS2 mutation screened by mismatch repair protein immunohistochemistry of colorectal cancer in Japan

Germline PMS2 gene mutations were detected by RT‐PCR/direct sequencing of total RNA extracted from puromycin‐treated peripheral blood lymphocytes (PBL) and multiplex ligation‐dependent probe amplification (MLPA) analyses of Japanese patients with colorectal cancer (CRC) fulfilling either the revised Bethesda Guidelines or being an age at disease onset of younger than 70 years, and screened by mismatch repair protein immunohistochemistry of formalin‐fixed paraffin embedded sections. Of the 501 subjects examined, 7 (1.40%) showed the downregulated expression of the PMS2 protein alone and were referred to the genetic counseling clinic. Germline PMS2 mutations were detected in 6 (85.7%), including 3 nonsense and 1 frameshift mutations by RT‐PCR/direct sequencing and 2 genomic deletions by MLPA. No mutations were identified in the other MMR genes (i.e. MSH2,MLH1 and MSH6). The prevalence of the downregulated expression of the PMS2 protein alone was 1.40% among the subjects examined and IHC results predicted the presence of PMS2 germline mutations. RT‐PCR from puromycin‐treated PBL and MLPA may be employed as the first screening step to detect PMS2 mutations without pseudogene interference, followed by the long‐range PCR/nested PCR validation using genomic DNA.

In situ synthesis of Au-shelled Ag nanoparticles on PDMS for flexible, long-life, and broad spectrum-sensitive SERS substrates

A simple, fast, one-step fabrication of silver nanoparticles with atomically thin gold coatings on polydimethylsiloxane affords oxidation-resistant and highly sensitive surface enhanced Raman scattering (SERS) substrates.

Cytoplasmic MSH2 immunoreactivity in a patient with Lynch syndrome with an EPCAM-MSH2 fusion

AIMS

Immunohistochemistry for mismatch repair (MMR) proteins is being increasingly used to examine MMR status in tumours. The aim of the present article was to report the case of a colon cancer patient with Lynch syndrome who showed unusual cytoplasmic MMR protein localization.

METHODS AND RESULTS

Histologically, the colon cancer was diagnosed as medullary carcinoma associated with prominent tumour-infiltrating lymphocytes and a Crohn's-like reaction. Immunohistochemistry revealed cytoplasmic and nuclear expression of MSH2 in non-neoplastic cells, and exclusively cytoplasmic expression in tumour cells. MSH6 expression was nuclear in non-neoplastic cells, but was lost in tumour cells. Nuclear expression of MLH1 and PMS2 was retained in both non-neoplastic and tumour cells. The tumour was microsatellite instability-high, which is indicative of defective MMR function. A subsequent germline mutation analysis identified a genomic deletion spanning the 3' region of EPCAM and the 5' region of MSH2, resulting in an in-frame fusion of EPCAM and MSH2.

CONCLUSIONS

The unusual cytoplasmic immunoreactivity of MSH2 was considered to be attributable to the non-functional EPCAM-MSH2 fusion product. The present case illustrates that not only loss of expression, but also abnormal localization, of MMR proteins is indicative of a defective MMR system.

Depressed-type submucosal invasive colorectal cancer in a patient with Lynch syndrome diagnosed using short-interval colonoscopy

Although regular colonoscopy surveillance is recommended for patients with Lynch syndrome (LS) who underwent partial colectomy, the appropriate interval has not been determined. We report a case of colorectal cancer (CRC) detected by short-interval surveillance colonoscopy (SC) in a patient with LS having a past history of partial colectomy. A 65-year-old man underwent sigmoidectomy for advanced CRC. His family history revealed that his two younger brothers had CRC in their twenties and thirties, respectively, and the patient met with the criteria in the Revised Bethesda Guidelines. After confirming the loss of MSH2 protein expression in the primary tumor, subsequent genetic testing showed germline mutation with a large deletion of exon 7-14 in the MSH2 gene, indicating a diagnosis of LS. After the diagnosis of LS, the patient underwent annual SC. Three years after the initial surgery, superficial submucosal invasive cancer was detected. Subsequently, SC after a 6-month interval revealed a deep submucosal invasive cancer (7 mm in diameter). Although additional surgery was recommended, considering his comorbidities, regular SC rather than colectomy was selected. Even shorter-interval SC carried out within a year is not sufficient to detect endoscopically resectable tumors in some high-risk LS cases.

Risk stratification and predictive risk-scoring model for lymph node metastasis in early gastric cancer

BACKGROUND

We are increasingly experiencing difficulty in deciding whether to perform gastrectomy after noncurative endoscopic resection of early gastric cancer (EGC) for patients at high risk for surgery. If the differences in risk for lymph node metastasis (LNM) on the basis of noncurative status are understood, the decision becomes easier. The present study aimed to stratify the LNM risk and develop and validate a risk-scoring model for predicting LNM.

METHODS

By retrospectively reviewing 3131 patients with solitary EGC who underwent gastrectomy with lymphadenectomy at our institution between July 1997 and May 2013, LNM risk was stratified and a risk-scoring model was developed on the basis of the identified independent risk factors for LNM. The scoring was validated using 352 other surgically resected EGC cases. The discriminatory accuracy of the scoring was measured by area under receiver operating characteristic curve (AUROC).

RESULTS

LNM was detected in 386 of 3131 cases. LNM risk in each subgroup, stratified by the identified independent risk factors, such as tumor size, depth, histological type, ulcerative findings, and lymphovascular involvement, considerably varied from 0 % to >50 % even among the current guidelines' noncurative subgroups. An 11-point scoring model was built, and AUROCs were 0.84 (95 % confidence interval, 0.82-0.86) and 0.82 (0.75-0.88) in the development and validation sets, respectively.

CONCLUSIONS

The present study revealed detailed LNM risk stratification data, and developed and validated an 11-point scoring model.

Frequent PTPRK-RSPO3 fusions and RNF43 mutations in colorectal traditional serrated adenoma

The molecular mechanisms underlying the serrated pathway of colorectal tumourigenesis, particularly those related to traditional serrated adenomas (TSAs), are still poorly understood. In this study, we analysed genetic alterations in 188 colorectal polyps, including hyperplastic polyps, sessile serrated adenomas/polyps (SSA/Ps), TSAs, tubular adenomas, and tubulovillous adenomas by using targeted next-generation sequencing and reverse transcription-PCR. Our analyses showed that most TSAs (71%) contained genetic alterations in WNT pathway components. In particular, PTPRK-RSPO3 fusions (31%) and RNF43 mutations (24%) were frequently and almost exclusively observed in TSAs. Consistent with the WNT pathway activation, immunohistochemical analysis showed diffuse and focal nuclear accumulation of β-catenin in 53% and 30% of TSAs, respectively. APC mutations were observed in tubular and tubulovillous adenomas and in a subset of TSAs. BRAF mutations were exclusively and frequently encountered in serrated lesions. KRAS mutations were observed in all types of polyps, but were most commonly encountered in tubulovillous adenomas and TSAs. This study has demonstrated that TSAs frequently harbour genetic alterations that lead to WNT pathway activation, in addition to BRAF and KRAS mutations. In particular, PTPRK-RSPO3 fusions and RNF43 mutations were found to be characteristic genetic features of TSAs. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.