Primary colorectal signet-ring cell carcinoma in Singapore

Systematic review of risk factors, prognosis, and management of colorectal signet-ring cell carcinoma

BACKGROUND

Colorectal signet-ring cell carcinoma (CSRCC) is a rare clinical entity which accounts for approximately 1% of all colorectal cancers. Although multiple studies concerning this specific topic have been published in the past decades, the pathogenesis, associated risk factors, and potential implications on treatment are still poorly understood. Besides the low incidence, historically confusing histological criteria have resulted in confusing data. Nevertheless, the rising incidence of CSRCC along with relatively young age at presentation and associated dismal prognosis, highlight the actual interest to synthesize the known literature regarding CSRCC.

AIM

To provide an updated overview of risk factors, prognosis, and management of CSRCC.

METHODS

A literature search in the MEDLINE/PubMed database was conducted with the following search terms used: 'Signet ring cell carcinoma' and 'colorectal'. Studies in English language, published after January 1980, were included. Studies included in the qualitative synthesis were evaluated for content concerning epidemiology, risk factors, and clinical, diagnostic, histological, and molecular features, as well as metastatic pattern and therapeutic management. If possible, presented data was extracted in order to present a more detailed overview of the literature.

RESULTS

In total, 67 articles were included for qualitative analysis, of which 54 were eligible for detailed data extraction. CSRCC has a reported incidence between 0.1%-2.4% and frequently presents with advanced disease stage at the time of diagnosis. CSRCC is associated with an impaired overall survival (5-year OS: 0%-46%) and a worse stage-corrected outcome compared to mucinous and not otherwise specified adenocarcinoma. The systematic use of exploratory laparoscopy to determine the presence of peritoneal metastases has been advised. Surgery is the mainstay of treatment, although the rates of curative resection in CSRCC (21%-82%) are lower compared to those in other histological types. In case of peritoneal metastasis, cytoreductive surgery with hyperthermic intraperitoneal chemotherapy should only be proposed in selected patients.

CONCLUSION

CSRCC is a rare clinical entity most often characterized by young age and advanced disease at presentation. As such, diagnostic modalities and therapeutic approach should be tailored accordingly.

A Rare Case of Signet Cell Carcinoma of Transverse Colon in a Young Patient With Ulcerative Colitis

Signet ring cell carcinoma (SRCC) represents an extremely rare histological type for colon cancer, accounting for less than 1% of all colon neoplasms. SRCC is usually aggressive and it is associated with poor prognosis. It can be divided into mucinous adenocarcinoma (MAC) with signet cells and signet cell of more than 50% of the tumor area. Main differential diagnosis is metastatic gastric signet cell carcinoma. A 27-year-old African American man with past medical history of ulcerative colitis on mesalamine presented to emergency department with complaints of diarrhea abdominal pain and shortness of breath for 3 weeks. Physical exam was remarkable for tachycardia with a heart rate (HR) of 106 and pallor otherwise normal. Laboratory data showed potassium 2.8 mmol/L, creatinine 1.11 mg/dL, lactic acid 8 mmol/dL, hemoglobin 2 g/dL and white blood cell count 21 × 10⁶/µL. Computed tomography (CT) scan of the abdomen with intravenous (IV) contrast showed distention of the colon, air-fluid levels and loss of haustra. Clostridium difficile stool PCR was positive. A clinical diagnosis of toxic megacolon due to C. difficile infection was made. Packed red blood cells (PRBCs) were transfused, and oral vancomycin and IV fluids were started. Symptoms and labs initially improved. However, on the third day, abdominal pain recurred with lactic acidosis. Diagnosis of refractory ulcerative colitis was made. Surgery was performed. Subtotal colectomy and ileostomy were done. Pathology revealed stage IV invasive signet ring cell adenocarcinoma, in the transverse colon poorly differentiated, with background of marked ulcerative colitis. Patient was started on adjuvant chemotherapy oxaliplatin, leucovorin and 5-flurouracil as an outpatient. Patient is undergoing 12 rounds of chemotherapy; he is currently in round 8 without complications. Patient is scheduled for screening colonoscopy and reversal of colostomy after completion of chemotherapy. SRCC of the colorectum is very rare, comprising less than 1% of colorectal cancer cases. It occurs mainly on the right colon and presents at later stages. Despite the rarity of this tumor, it is associated with ulcerative colitis. The main differential diagnosis is a metastasis from gastric signet cell carcinoma. It is associated with a poor prognosis.

Genomic alterations in signet ring and mucinous patterned colorectal carcinoma

BACKGROUND

The genetic alterations (GAs) in two specific histological subtypes of colorectal cancer (CRC), signet ring cell colorectal carcinoma (SRC) and mucinous colorectal carcinoma (MC), are not well known. In the present study, we employed next-generation sequencing to perform genetic profiling of SRC and MC, and compared the spectrum of GAs with the alterations found in conventional type colorectal cancer (CON).

MATERIALS AND METHODS

We selected 46 CRCs comprising 17 SRCs and mucinous carcinoma with signet ring cell component (SRCCs), 17 MCs, and 12 CONs with microsatellite stability or microsatellite instability-low. Deep sequencing was performed using a targeted cancer panel composed of 171 cancer-related genes. SMAD4 protein expression was evaluated by immunohistochemical staining.

RESULTS

We detected 108 mutations in 18 different genes. Overall, 2.34 GAs were detected per tumor (range, 0-14). The overall frequency of GA and alteration in targetable genes was less prevalent in SRC/SRCC compared to the frequency of alteration in MC/CON (p = 0.040 and p < 0.001, respectively). The GA profile of SRC/SRCC included TP53 (8/17, 47.1%), SMAD4 (5/17, 29.4%), KRAS (4/17.23.5%), APC (4/17.23.5%), PIK3CA, ATM, BRAF, and PIK3R1 (1/17, 5.9%, each). KRAS mutation was significantly less prevalent in SRC/SRCC compared to the number of KRAS mutations in MC (12/17, 70.6%) and CON (9/12, 75.0%) (p = 0.015 and 0.01, respectively). Compared to the 152 non-hypermutated CONs from TCGA database, SMAD4 alteration was predominant in SRC/SRCC (p = 0.045) with aberrant loss of SMAD4 expression (13/17, 76.5%) compared to the SMAD4 alterations in CON (5/15, 33.3%) (p = 0.031). Accordingly, KRAS (12/17, 70.6%), APC (6/17, 35.3%), SMAD4, TP53 (4/17, 23.5%, each), PIK3CA (3/17, 17.6%), AKT1, ATM, BRAF, EGFR, and EZH2 (1/17, 5.9%, each) were altered in MC. APC and TP53 mutations were less frequent in MC compared to those in TCGA-CON (p < 0.001 and 0.003, respectively) whereas KRAS mutation was prevalent (p = 0.041).

CONCLUSION

Alterations of known cancer associated genes and targetable genes in SRC/SRCC are infrequent. The profile of GAs in SRC/SRCC and MC differs from the GA profile of CON. Specifically, SMAD4 mutation and loss of SMAD4 expression is frequently found in SRC/SRCC. The genetic profiles revealed in the present study may aid in developing precision medicine for CRC treatment based on histological subtype.

Characteristics and prognostic factors of colorectal mucinous adenocarcinoma with signet ring cells

Background

Colorectal signet ring cell (SRC) carcinoma occurs rarely with a poor prognosis. The present study assessed the prognostic factors and predictive value of SRC ratio in colorectal mucinous adenocarcinoma (MAC) with SRCs (MAC-SRC).

Patients and methods

A total of 95 consecutive colorectal MAC-SRC patients, confirmed pathologically from February 1987 to December 2015, were analyzed retrospectively in our institute. Clinical characteristics, pathological grade, TNM staging, and SRC ratio were assessed to identify the prognostic factors related to progression-free survival (PFS) and overall survival (OS). SPSS 22.0 was used for statistical analyses.

Results

The median follow-up time was 29.7 months (range 0.8–165). Meanwhile, 5-year PFS and OS rates were 25.6% (95% confidence interval [CI] 16.192–35.008%) and 40.5% (95% CI 29.524–51.476%), respectively. Among the 81 patients who underwent surgery, 78 (96.3%) were diagnosed as stage T3 or T4; 74 (91.4%) showed lymph node involvement, and 27 (29.3%) presented distant metastasis. Metastases of the peritoneal cavity and ovaries were observed commonly in colorectal MAC-SRC. In the multivariate Cox regression model, SRC ratio ≥35%, absence of preoperative radiotherapy, and distant metastasis were independent predictors of PFS. Furthermore, SRC ratio ≥35%, absence of preoperative chemotherapy (pre-CT), and distant metastasis were independent risk factors for poor prognosis.

Conclusion

A long-term follow-up of colorectal MAC-SRC reveals that it is a rare subtype of colorectal MAC with a dismal prognosis. Furthermore, SRC ratio, pre-CT, and M stage seem to affect OS independently.

Clinical Analysis of Primary Colorectal Signet-Ring Cell Carcinoma

The objective of the study was to investigate the clinicopathological features of primary colorectal signet-ring cell carcinoma. We retrospectively analyzed the clinical and survival data of 37 patients with primary colorectal signet-ring cell carcinoma. The mean survival time of patients in stage II, III, and IV were estimated using Student t test and the cumulative survival rates were estimated according to the method of Kaplan-Meier. The significance of the differences in survival rates were calculated using the log rank test. The incidence of primary colorectal signet-ring cell carcinoma was 1.40%, the median age of 37 patients was 50 years, the male to female ratio was 1.47:1, and 21 patients (56.8%) received a radical resection. Most patients 33 (89.2%) had an advanced tumor stage at the time of diagnosis (17 patients 45.9% stage III and 16 patients 43.2% stage IV), 34 (94.5%) patients showed a tumor depth of >T3, lymph node involvement occurred in 26 patients (70.3%), patients had a high incidence of peritoneal metastasis (16 patients 43.2% at presentation, 30 patients 81.1% at presentation and recurrence) and a low incidence of liver metastases (1 patients 2.7% at presentation, 5 patients 13.5% at presentation and recurrence). The 5-year survival rate after the initial surgery was 10.8%, the mean survival time of 37 patients was 27.1 ± 3.3 months, the mean survival time of patients in stage II, III, and IV were 47.0 ± 12.8 months, 37.1 ± 3.9 months, and 10.5 ± 1.4 months, respectively (P < .000). Colorectal signet-ring cell carcinoma is a rare neoplasm with a predominance in men. Its characteristic features were the advanced stage at the time of diagnosis, a high incidence of peritoneal metastases, a low incidence of liver metastasis, and a poor prognosis.

Signet ring cell carcinoma of resectable metastatic colorectal cancer has rare surgical value

BACKGROUND AND OBJECTIVES

Signet ring cell carcinoma (SRCC) is a uniquely separated subgroup in metastatic colorectal cancer (mCRC). The aims are to investigate the value of resection in patients with resectable metastatic signet ring cell colorectal cancer.

METHODS

Patients with mCRC who underwent resection in Surveillance, Epidemiology, and End Results database during 1998-2010 were retrospectively analyzed. Kaplan-Meier and COX models were used to analyze the differences in the survival. Logistic regression models were used to evaluate the relationship between SRCC and other clinicopathological factors.

RESULTS

Among the 3,568 patients, 94 (2.63%) patients had SRCC. The median survival time of patients with SRCC and non-SRCC were 17 and 29 months, respectively (P < 0.001). Multivariate analysis indicated that SRCC was an independent prognostic factor for poor overall survival. Logistic regression model based on variables identified by univariate analysis indicated that younger age (≤50 years old) (P = 0.005), female (P < 0.001), location in colon (P = 0.012), and N positive status (P = 0.003) were independent variables correlated with the SRCC subgroup. SRCC had a dramatically higher invalid surgical outcome rate than non-SRCC (P = 0.001).

CONCLUSION

SRCC patients might benefit little from the resection of primary and metastatic lesions with a high rate of undergoing invalid operations. J. Surg. Oncol. 2016;114:1004-1008. © 2016 Wiley Periodicals, Inc.

Younger Age Is Associated with Poorer Survival in Patients with Signet-Ring Cell Carcinoma of the Colon without Distant Metastasis

Background. In general, younger age is associated with better survival in patients with colon cancer. In this study, we aim to analyze the impact of age on cancer-specific survival (CSS) in patients with signet-ring cell carcinoma (SRCC) of the colon, a particularly aggressive type of colon cancer. Methods. Information on patients with SRCC of the colon with no distant metastasis was extracted from the US Surveillance, Epidemiology, and End Results (SEER) database. An X-tile plot was used to determine the optimal cutoff age at diagnosis. Results. A total of 776 patients were included in data analysis. The X-tile program revealed an optimal cutoff at 35 years of age. A higher percentage of stage III disease and a higher percentage of N2 disease were observed in patients ≤ 35 years of age. The multivariate Cox proportional model demonstrated that patients ≤ 35 years of age were more likely to have a poorer survival outcome compared with patients aged >35 years (HR 1.411, 95% CI 1.032–1.929, and P = 0.031). Conclusion. In contrast to the association of younger age with better survival in colon cancer patients, younger age (≤35 years) is associated with poorer survival outcome in patients with SRCC of the colon without distant metastasis.

The Characteristics and Prognostic Effect of E-Cadherin Expression in Colorectal Signet Ring Cell Carcinoma

Purpose

Signet ring cell carcinoma (SRCC) is rare. The aim of this study is to understand the clinicopathological features and identify the possible prognostic factors in colorectal SRCC.

Methods

Patients with SRCC who underwent primary lesion resection at Fudan University Shanghai Cancer Center from September 2008 to July 2014 were retrospectively analyzed. Patient’s gender, age, tumor location, depth of invasion, lymph node metastasis, synchronous distant metastasis, perineural invasion, lymphovascular invasion, and E-cadherin expression were studied with prognosis, and the correlation between E-cadherin expression and clinicopathological features were analyzed. All clinicopathological and molecular factors were put into multivariate analysis using Cox proportional hazards model for detecting independent prognostic factors.

Results

59 patients accounting for 0.89% of total colorectal cancer patients met the criteria and were enrolled in the study. The median survival time is 28.9 months, and the 3-year survival rate is 62.7%. SRCC were seen more common in young male patients. Advanced stage was more common in SRCC, 58 (98.3%) patients had T3/T4 lesions, 52 (88.1%) patients had lymph node metastasis, and 14 (23.7%) patients had distant metastasis. Distant metastases were seen more common in peritoneal cavity. Distant metastasis (HR = 4.194, 95% CI: 1.297–13.567), lymphovascular invasion (HR = 2.888, 95% CI: 1.115–7.483), and E-cadherin expression (HR = 0.272, 95% CI: 0.096–0.768) were independent predictors for survival.

Conclusions

SRCC is a rare subtype of colorectal cancer with poor prognosis. Distant metastasis, lymphovascular invasion, and E-cadherin expression can predict prognosis of colorectal SRCCs independently. More precise therapy and more close surveillance are needed for these patients.

Odd localisation for a gastric cancer histology

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More than 96% of signet-ring cell carcinomas occur in the stomach.

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Primary SRC carcinoma of the colon and rectum is very rare.

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It spreads mainly to the lymph nodes and to the peritoneum and rarely to the liver.

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It presents at advanced stages and has a dismal prognosis.

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Upper endoscopy is the investigation of choice to exclude a primary gastric cancer.

Introduction

More than 96% of signet-ring cell carcinomas occur in the stomach and the rest in other organs, including the gallbladder, pancreas, urinary bladder and breast. Primary signet-ring cell carcinoma of the colon and rectum is very rare, accounting for 0.1%–2.4% of all colorectal cancers.

Presentation of case

We report a case of a 55-year old man who is operated for a caecal mass evocative of an appendicitis abscess. Intraoperatively, we discover a large, ulcerated ilio-caecal mass with several lymphadenopathies. The further workup reveals a primary signet-ring cell carcinoma of the colon with multiple lymph nodes and osteolytic bony metastases.

Discussion

Primary signet-ring cell carcinoma of the colon and rectum presents usually as an advanced stage disease with a dismal prognosis. It spreads mainly to the lymph nodes and to the peritoneum and very rarely to the liver. The mean age of patients diagnosed with primary signet-ring cell carcinoma is significantly younger than for ordinary adenocarcinoma. The upper endoscopy is the investigation of choice to exclude a primary gastric pathology. There are very few reports about this type of cancer and no reports about this type of cancer associated with osteolytic bony metastases.

Conclusion

The characteristics and pathophysiology of a primary signet-ring cell carcinoma of the colon and rectum are not well understood. Usually only palliative treatment is possible. The importance of an early diagnosis of this tumor is mandatory to have a curative approach.

Clinicopathologic and Molecular Features of Colorectal Adenocarcinoma with Signet-Ring Cell Component

Background

We performed a retrospective study to assess the clinicopathological characters, molecular alterations and multigene mutation profiles in colorectal cancer patients with signet-ring cell component.

Methods

Between November 2008 and January 2015, 61 consecutive primary colorectal carcinomas with signet-ring cell component were available for pathological confirmation. RAS/BRAF status was performed by direct sequencing. 14 genes associated with hereditary cancer syndromes were analyzed by targeted gene sequencing.

Results

A slight male predominance was detected in these patients (59.0%). Colorectal carcinomas with signet-ring cell component were well distributed along the large intestine. A frequently higher TNM stage at the time of diagnosis was observed, compared with the conventional adenocarcinoma. Family history of malignant tumor was remarkable with 49.2% in 61 cases. The median OS time of stage IV patients in our study was 14 months. RAS mutations were detected in 22.2% (12/54) cases with KRAS mutations in 16.7% (9/54) cases and Nras mutations in 5.4%(3/54) cases. BRAF V600E mutation was detected in 3.7% (2/54) cases. As an exploration, we analyzed 14 genes by targeted gene sequencing. These genes were selected based on their biological role in association with hereditary cancer syndromes. 79.6% cases carried at least one pathogenic mutation. Finally, the patients were classified by the percentage of signet-ring cell. 39 (63.9%) cases were composed of ≥50% signet-ring cells; 22 (36.1%) cases were composed of <50% signet-ring cells. We compared clinical parameters, molecular and genetic alterations between the two groups and found no significant differences.

Conclusions

Colorectal adenocarcinoma with signet-ring cell component is characterized by advanced stage at diagnosis with remarkable family history of malignant tumor. It is likely a negative prognostic factor and tends to affect male patients with low rates of RAS /BRAF mutation. Colorectal patients with any component of signet-ring cells, regardless of the extent, shared similar clinicopathological characteristics, molecular alterations and genetic profiles.

Clinical Features and Prognosis of Resectable Primary Colorectal Signet-Ring Cell Carcinoma

BACKGROUND/AIMS

We attempted to investigate the prognosis of signet-ring cell carcinoma (SRC) patients who underwent curative surgery by comparing them with age-, sex-, and stage-matched non-mucinous adenocarcinoma (NMAC) patients.

METHODS

Between January 2003 and December 2011, 19 patients with primary SRC of the colorectum underwent curative surgery. Four SRC patients under the age of 40 were excluded, and the clinicopathological data of 15 patients (7 men; median age, 56 years) were reviewed and compared with the data of 75 NMAC patients matched by age, sex, and pathologic stage.

RESULTS

The median follow-up duration was 30.1 months for the SRC group and 43.7 months for the NMAC group (P=0.141). Involvement of the left side of the colon (73.3% vs. 26.7%, P=0.003) and infiltrative lesions such as Borrmann types 3 and 4 (85.7% vs. 24.0%, P=0.001) were more common in the SRC group than in the NMAC group. The five-year overall survival rate was significantly lower for patients with SRC than for those with NMAC (46.0% vs. 88.7%, hazard ratio, 6.99; 95% confidence interval, 2.33-20.95, P=0.001).

CONCLUSIONS

Patients with even resectable primary colorectal SRC had a poorer prognosis than age-, sex-, and stage-matched colorectal NMAC patients.

Primary signet ring cell carcinoma of the colon and rectum

Colorectal primary signet ring cell carcinoma (SRCC) is a rare entity accounting for nearly 1% of all colorectal carcinomas. It is an independent prognostic factor associated with less favorable outcome. This aggressiveness is mainly due to the intrinsic biology of these tumors. Here is an overview of the literature related to clinicopathological features, molecular biology, and management of SRCC of the colon and the rectum.

Exploring signet-ring cells in pregnant female

INTRODUCTION

Primary signet-ring cell carcinoma (SRCC) of the colon and rectum are rare form, which present at an advanced stage and have poor prognosis. Different treatment policies of SRCC during different gestational age of pregnancy are explored from the literature.

CASE STUDY

A 26-year-old young pregnant female with 10-week gestation presented with constipation and blood in stools and on per rectal examination a tender circumferential stricture was present 2 cm above the anal verge. Magnetic resonant imaging (MRI) pelvis of the patient revealed rectal thickening, the biopsy of which revealed characteristic appearance of "linitis plastica" and diagnosed as poorly differentiated adenocarcinoma with signet ring morphology with wide spread positivity for cytokeratin & p53. With this diagnosis, patient underwent medical termination of pregnancy (MTP).

DISCUSSION

SRCC of the colon comprises about only 1% of all cases of colon cancer. When compared with other types of adenocarcinoma, patients with SRCC in the colon are younger and more likely to experience lymph node metastasis. Its incidence in pregnancy is estimated to be less than 0.1%. Certainly, any pregnant patient who reports rectal bleeding or has hemoccult positive stool on examination deserves careful evaluation to rule out cancer. The complex treatment of colorectal cancer in pregnancy is based on the gestational age of the fetus, tumor stage and need for emergent vs. elective management.

A minor (<50%) signet-ring cell component associated with poor prognosis in colorectal cancer patients: a 26-year retrospective study in China

Background

We performed a retrospective study to determine the cancer-specific survival of colorectal cancer patients with a component of signet-ring cells or mucin comprising < 50% of the tumor mass.

Methods

A total of 2454 patients seen in our hospital from 1985 to 2011 were retrospectively studied. The patients were divided into five groups according to type of cancer: signet-ring cell carcinoma (with > 50% signet-ring cell, n = 36), partial signet-ring cell carcinoma (with < 50% signet-ring cell, n = 28), mucinous adenocarcinoma (with > 50% mucin lacking signet-ring cell, n = 267), partial mucinous adenocarcinoma (with < 50% mucin lacking signet-ring cell, n = 145), and classic adenocarcinoma (with absence of either mucin or signet-ring cell, n = 1978).

Results

Patients with > 50% or < 50% signet-ring cell had the lowest 5-year survival rates (35.5% and 29.7%, respectively), followed by patients with > 50% mucin (48.8%). Patients who had partial mucinous adenocarcinoma with < 50% mucin and classic adenocarcinoma patients had the highest 5-year survival rates (64.8% and 65.3%, respectively). Stratified and multivariate analysis showed that signet-ring cell carcinoma, partial signet-ring cell carcinoma and mucinous adenocarcinoma were independent predictors of decreased survival (hazard ratio 1.699, P = 0.016; hazard ratio 2.182, P = 0.005; hazard ratio 1.532, P < 0.001; respectively), and partial mucinous adenocarcinoma was not (hazard ratio 1.137, P = 0.431).

Conclusions

Patients with a component of signet-ring cells, regardless of the extent, had poor prognoses. Patients with mucinous adenocarcinoma containing >50% mucin had poor prognoses as well, whereas those with < 50% mucin had survival rates similar to those of classic adenocarcinoma patients. Therefore, in clinical practice, patients with a component of signet-ring cells, regardless of the extent, should be given significant clinical attention.

Synchronous appendiceal and intramucosal gastric signet ring cell carcinomas in an individual with CDH1-associated hereditary diffuse gastric carcinoma: a case report of a novel association and review of the literature

Background

Hereditary diffuse gastric carcinoma is an autosomal dominant cancer syndrome associated with mutations of the E-cadherin gene (CDH1). E-cadherin is normally involved in cell-cell adhesion, so it not surprising that individuals with this syndrome are predisposed to develop malignancies with dyshesive morphologies at a young age, such as diffuse (signet ring cell) gastric carcinoma and lobular breast carcinoma. Herein we describe the first reported case of primary appendiceal signet ring cell carcinoma arising in a CDH1-associated hereditary diffuse gastric carcinoma kindred with synchronous primary diffuse gastric carcinoma.

Case presentation

A 51- year old woman, with known CDH1 mutation carrier status and a prior history of lobular breast carcinoma underwent prophylactic total gastrectomy which revealed multifocal intramucosal signet ring cell carcinoma. An appendectomy was performed at the same time due to a prior episode of presumed appendicitis, with pathologic examination significant for a primary signet ring cell carcinoma of the appendix.

Conclusion

As appendiceal signet ring cell carcinoma is exceedingly rare, the occurrence of this neoplasm in this patient, with this particular morphology, provides credence for it being part of the hereditary diffuse gastric carcinoma spectrum of malignancies.

Early-stage primary signet ring cell carcinoma of the colon

Primary signet ring cell carcinoma of the colorectum detected at an early stage is very rare; most cases are detected at an advanced stage. Therefore, its prognosis is poorer than that of ordinary colorectal cancer. A 56-year-old Korean man was seen at this hospital for management of signet ring cell carcinoma of the colon. Colonoscopic examination revealed a IIa-like, ill-defined and flatly elevated 9-mm residual tumor in the cecum. Endoscopic mucosal resection was preformed. Pathological examination of the resected specimen revealed signet ring cell carcinoma that had invaded the lamina propria without venous or perineural invasion. Abdominal computed tomography (CT) and positron CT showed no evidence of primary lesions or distant metastasis. An additional laparoscopic right-hemicolectomy was performed; no residual tumor or lymph node metastasis was found. We report a case of primary signet ring cell carcinoma of the colon detected at an early stage and provide a review of the literature.

Mucinous colorectal adenocarcinoma with signet-ring cells: immunohistochemical and ultrastructural study

A primary mucinous colorectal adenocarcinoma tissue with signet-ring cells, as revealed after histological evaluation, was examined ultrastructurally. The authors also analyzed the immunohistochemical data of the tissue for serotonin, vasoactive intestinal polypeptide (VIP), bombesin, somatostatin, and glucagon, using the peroxidase anti-peroxidase (PAP) method and the immunogold labeling method for light and electron microscope, respectively. Electron microscopically mucinous adenocarcinoma was characterized by the formation of small lumen. Adenocarcinoma cells were full of mucous granules of varying electron density, providing a good environment for the tumor cells to grow. They also exhibited a significant loss of microvilli and intracytoplasmic junctions, which could allow the cells to disseminate. Signet-ring cells were located in the basal site of the ducts or in the lamina propria and appeared neoplastic, with mucin accumulation intracellularly and an eccentric crescent-shaped nucleus. The cytoplasmic organelles were decreased and at the periphery of the cell. The PAP method demonstrated that these cells were strongly positive for bombesin and also positive for vasointestinal polypeptide (VIP). The immunogold method detected bombesin immunoreactivity in the vacuoles as well as in other cytoplasmic membranes, whereas VIP was localized mainly in the plasma membrane. The location of signet-ring cells combined with the immunoreactivity for bombesin and VIP indicated that signet-ring cells were of neuroendocrine origin and probably dedifferentiated enterochromaffin-like endocrine cells. These findings have implications for understanding the biological behavior of these composite malignant tumors and could help in the knowledge of the origin of signet-ring cells.

Signet-ring cell carcinoma of colorectum--current perspectives and molecular biology

PURPOSE

Colorectal signet-ring cell carcinoma (SRCC) is rare, and very little detailed information on the molecular biology of the disease is available.

METHODS

The literature on the clinical, pathological and, in particular, the molecular biology of this rare entity was critically reviewed. The reviewed articles take into account a total of 1,817 cases of SRCC, but only 143 cases have molecular data available. The characteristics of two patients with colorectal SRCC were also discussed.

RESULTS

Colorectal SRCC mostly occurs in younger patients, is larger and has different site predilection compared with conventional colorectal adenocarcinoma. It can occur as one of the synchronous cancers in the colorectum. The cancer is usually diagnosed at advanced stages because of the late manifestation of symptoms, and aggressive treatment strategy is required. Limited reports in the literature have shown that the variant of colorectal cancer demonstrated a different pattern of genetic alterations of common growth kinase-related oncogenes (K-ras, BRAF), tumour suppressor genes (p53, p16), gene methylation and cell adhesion-related genes related to the Wingless signalling pathway (E-cadherin and beta-catenin) from conventional colorectal adenocarcinoma. Colorectal SRCC also showed high expression of mucin-related genes and genes related to the gastrointestinal system. There was also a higher prevalence of microsatellite instability-high tumours and low Cox-2 expression in colorectal SRCC as opposed to conventional adenocarcinoma.

CONCLUSIONS

Colorectal SRCC has unique molecular pathological features. The unique molecular profiles in SRCC may provide molecular-based improvements to patient management in colorectal SRCC.

Critical analysis of mucin and signet ring cell as prognostic factors in an Asian population of 2,764 sporadic colorectal cancers

INTRODUCTION

Conflicting data on the clinicopathological characteristics as well as prognosis and survival of signet ring cell (SRC) and mucinous adenocarcinomas (MA) of the colorectum persist.

METHODS

Consecutive patients (2,764) with sporadic colorectal cancer from 1999 to 2005 were evaluated. The clinicopathological characteristics of these patients were reviewed. Univariate analysis was performed, and survival curves were constructed using the Kaplan-Meier method. Multivariate analysis assessed independent prognostic factors.

RESULTS

The incidence of MA and SRC is 6% and 1.1%, respectively. MA and SRC tend to occur in patients aged <or=50 years (SRC 33%, MA 22%, ordinary adenocarcinomas (OA) 14%, p = 0.001) and are more commonly right-sided (MA 30%, SRC 27%, OA 19%, p = 0.001) than OA. SRC tend to be poorly differentiated (SRC 77%, MA 26%, OA 6%, p < 0.0001) and have a higher risk of recurrence (SRC 40%, MA 26%, OA 6%, p < 0.0001). SRC and MA are more likely to have locally advanced lesions (T3/T4; SRC 100%, MA 90%, OA 83%, p = 0.002) and lymph node metastases (SRC 89%, MA 61%, OA 52%, p < 0.0001) and present with an advanced stage at diagnosis (stage III/IV SRC 94%, MA 67%, OA 56%, p < 0.0001). SRC has poorer 5-year cancer-specific survival (CSS; 11.1%, 95% confidence interval (CI) 0-22.9%) compared with MA (46.8%, 95% CI 38.6-55.0%) and OA (58.7%, 95% CI 56.5-60.9%, p < 0.001). In a multivariate analysis, SRC is an independent poor prognostic factor (HR 1.9, 95% CI 1.1-3.0) but MA is not.

CONCLUSION

SRC and MA demonstrate clinicopathologic characteristics suggestive of a different biology compared with OA. In our dataset, SRC has a significantly poorer CSS whereas survival rates for MA are similar to OA. These characteristics are similar in both Asian and Western studies reported. Asian reports however suggest a lower incidence of MA.

Primary colorectal signet-ring cell carcinoma: clinicopathological features and postoperative survival

PURPOSE

The objective of this study was to investigate the clinicopathological features and postoperative survival of primary colorectal signet-ring cell carcinoma.

METHODS

Nineteen patients with primary colorectal signet-ring cell carcinoma were identified from a database of 5884 surgical patients with colorectal cancers treated surgically at Osaka University Hospital and affiliated hospitals between 1993 and 2007. The clinicopathological data of those patients were compared with those of 5792 patients with non-signet-ring cell colorectal carcinoma (5417 with well or moderately differentiated adenocarcinoma and 375 with poorly differentiated adenocarcinoma or mucinous carcinoma).

RESULTS

All patients showed a tumor depth of over T3. Lymph node involvement occurred in 14 patients. Seven of 19 patients presented with distant metastasis at the time of diagnosis. The overall 5-year survival rate in primary signet-ring cell carcinoma was significantly lower at 24.1%, in comparison to 77.5% in well or moderately differentiated adenocarcinoma and 57.7% in poorly differentiated adenocarcinoma or mucinous carcinoma. Likewise, the postoperative survival in Stage III was also significantly worse. On the other hand, no significant difference was observed in Stage II or IV.

CONCLUSION

The most important feature of primary colorectal signet-ring cell carcinoma is the advanced stage at the time of diagnosis. In addition, the postoperative survival is worse than for other types of colorectal cancer.

Critical analysis of 33 patients with peritoneal carcinomatosis secondary to colorectal and appendiceal signet ring cell carcinoma

BACKGROUND

Primary signet-ring cell carcinoma (SRC) of colorectal and appendiceal origin is a rare entity with an aggressive biology and clinical behavior. The majority of patients develop peritoneal carcinomatosis (PC) early in the disease. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) may potentially improve survival.

METHODS

An observational study of 33 patients with SRC of colorectal or appendiceal origin was identified through a retrospective review of two peritoneal surface malignancy databases between January 1997 and December 2008. Survival analysis was performed using the Kaplan-Meier method.

RESULTS

Thirty-three patients (18 women (55%); mean age at diagnosis of carcinomatosis, 49 (standard deviation = 12) years) were identified to have SRC, with 15 cases of colorectal and 18 of appendiceal origin. For patients with colonic SRC who underwent complete CRS and HIPEC versus systemic chemotherapy only, the median survival was 13 and 18 months (P = 0.75). For patients with appendiceal SRC who underwent complete CRS and HIPEC versus systemic chemotherapy only, the median survival was 27 and 15 months (P = 0.12).

CONCLUSIONS

There seems to be less survival benefits after a complete CRS and HIPEC as a curative treatment for PC from colorectal SRC compared with that for non-SRC colorectal adenocarcinoma. However, in patients with appendiceal SRC, long-term survival is a reality after treatment.

Diallyl disulfide induces apoptosis in human colon cancer cell line (COLO 205) through the induction of reactive oxygen species, endoplasmic reticulum stress, caspases casade and mitochondrial-dependent pathways

In this study, we investigated the effects of DADS on human colon cancer cell line COLO 205 on cell cycle arrest and apoptosis in vitro. After 24 h treatment of COLO 205 cells with DADS, the dose- and time-dependent decreases of viable cells were observed and the IC50 was 22.47 microM. The decreased percentages of viable cells are associated with the production of ROS. Treatment of COLO 205 cells with DADS resulted in G2/M phase arrest and apoptosis occurrence through the mitochondrial-pathway (Bcl-2, Bcl-xL down-regulation and Bak, Bax up-regulation). DADS increased cyclin B, cdc25c-ser-216-9 and Wee1 but did not affect CDK1 protein and gene expression within 24 h of treatment. DADS-induced apoptosis was examined and confirmed by DAPI staining and DNA fragmentation assay. DADS promoted caspase-3, -8 and -9 activity and induced apoptosis were accompanied by increasing the levels of Fas, phospho-Ask1 and -JNK, p53 and decreasing the mitochondrial membrane potential which then led to release the cytochrome c, cleavage of pro-caspase-9 and -3. The COLO 205 cells were pre-treated with JNK inhibitor before leading to decrease the percentage of apoptosis which was induced by DADS. Inhibition of caspase-3 activation blocked DADS-induced apoptosis on COLO 205 cells.

HNPCC-associated synchronous early-stage signet-ring cell carcinomas of colonic origin. A comparative morphological and immunohistochemical study of an intramucosal and a submucosal example

Signet-ring cell carcinoma (SRCC) developing in the colorectum (CR) is infrequently identified at an early stage (no deeper than submucosa). Most such examples involve the submucosa. Merely 13 cases of intramucosal CR SRCC are at hand. We recently had the opportunity to study a specimen with two synchronous early-stage SRCC, developed in a 65-year-old hereditary nonpolyposis colorectal cancer male patient with a known disease-causing mutation in MLH1. A right hemicolectomy specimen comprised a 15-mm intramucosal cecal lesion, featuring zones of conventional tubular adenoma and intraepithelial SRCC as well as tumor cells multifocally permeating the lamina propria and a 12-mm submucosally expanding SRCC of the ascending colon. The intramucosal and intraepithelial as well as stromal lesional cells displayed a normal membranous expression of beta-catenin and E-cadherin; submucosally infiltrating cells featured alterations in this complex with loss of membranous expression of both proteins and a shift with nuclear accumulation of beta-catenin, suggesting a disruption of the Wingless signaling pathway taking place at the transition from the intramucosal to the submucosal level.

Primary colonic signet ring cell carcinoma presenting carcinocythemia: an autopsy case

Primary colorectal signet ring cell carcinoma (SRCC) is a rare but distinctive type of mucin-producing adenocarcinoma of the large intestine with still controversial clinicopathological features and prognosis. We encountered primary colonic SRCC in a 51-year-old Japanese man with extensive bone metastasis ultimately leading to carcinocythemia before the initiation of chemotherapy and surgical intervention. Three days before death, besides progressive disseminated intravascular coagulation that had been present on admission, hematological examination showed sudden leukocytosis with nonhematopoietic cells that subsequently turned out to be signet ring cells (SRCs). Carcinocythemia, the presence of circulating cancer cells in peripheral blood, is considered to be a rare but an ominous phenomenon occurring in the advanced stage of certain types of cancers, particularly mammary lobular carcinoma. It can be assumed that carcinoma cells lacking intercellular cohesiveness and polarized cell membrane organization, including SRCs as well as lobular carcinoma cells, can readily get access to the peripheral circulation; however, to our knowledge, this is the first report of primary colorectal SRCC that presented carcinocythemia. Extensive bone metastatic sites, in the present case, may have functioned as a reservoir of circulating SRCs.

Primary rectal signet ring cell carcinoma with peritoneal dissemination and gastric secondaries

Disseminated signet ring cell carcinomas frequently arise from the stomach. However, primaries in the colon and rectum have also been reported. We present a 68 year old lady who presented with a change in her bowel habit. Colonoscopy showed a stenosing rectal tumour at 7 cm to 8 cm from the anal verge. Multiple scattered ulcers were also noted along the entire length of the colon. Biopsy of the lesions revealed signet ring cell adenocarcinoma. Gastroscopy showed multiple nodules with ulceration over several areas of the stomach which were similar in appearance to the colonic lesions. However, no primary tumour of the stomach was seen. Biopsy of the gastric lesions also showed signet ring cell adenocarcinoma. Computed tomography scan of the abdomen and pelvis revealed circumferential tumour at the rectosigmoid junction with possible invasion into the left ischiorectal fossa. The overall picture was that of a primary rectal signet ring cell carcinoma with peritoneal dissemination. The patient was referred for palliative chemotherapy in view of the disseminated disease. In the present report, we discuss this interesting pathological entity and review the role of various histolological techniques in helping to identify the primary tumor.

Significance of signet-ring cells in patients with colorectal cancer

PURPOSE

We performed a retrospective study to determine the pattern of metastases and overall outcome of patients with tumors exhibiting a component of signet-ring cells comprising < 50 percent of the tumor mass.

METHODS

Medical records of 753 patients with primary colorectal cancer were retrospectively studied. Patients who had tumors with < 50 percent signet-ring cells were classified as having a component of signet-ring cells. The outcome of patients with a component of signet-ring cells was compared to all patients with mucinous adenocarcinoma (defined as adenocarcinomas with > or = 50 percent mucin) to all patients with adenocarcinomas with a component of mucin (defined as adenocarcinomas with < 50 percent mucin) and to 100 randomly selected patients with adenocarcinomas lacking mucin or signet-ring cells.

RESULTS

Five percent of patients had a component of signet-ring cells, 3 percent had mucinous adenocarcinoma, 9 percent had a component of mucinous adenocarcinoma, and 83 percent had adenocarcinoma lacking mucinous or signet components. Patients with a component of signet-ring cells and mucinous adenocarcinomas metastasized predominantly to the peritoneum/ovaries (75 and 56 percent of metastatic cases, respectively) and rarely to liver/lungs. The pattern of metastases of patients with adenocarcinoma without mucinous or signet components predominantly involved the liver/lungs and rarely the peritoneum/ovaries (12.5 percent). The pattern of metastases for patients with a component of mucinous adenocarcinoma was intermediate between mucinous adenocarcinoma and adenocarcinoma without mucin or signet-ring component. No differences in survival in Stage IV patients were seen among the four subgroups.

CONCLUSIONS

Patients with a component of signet-ring cells cancers, similar to mucinous adenocarcinoma, have a predisposition to metastasize to the peritoneum/ovaries.

Treatment outcomes in patients with signet ring cell carcinoma of the colorectum

BACKGROUND

The aim of this study was to evaluate the clinicopathologic features and prognosis of signet ring cell (SRC) carcinoma and compare them with those of mucinous and poorly differentiated adenocarcinomas of the colorectum.

METHODS

The clinicopathologic data of 35 patients with primary SRC carcinoma were reviewed and compared with the data from 294 patients with mucinous and 252 patients with poorly differentiated adenocarcinoma.

RESULTS

Eighty percent of the SRC patients presented with more advanced disease (stages III and IV), whereas 55.1% and 64.7% of the patients in the mucinous and poorly differentiated groups had advanced disease at diagnosis, respectively (80% vs 55.1%, P = .04 and 80.0% vs 64.7%, P = .437). Median survival time for patients with SRC was 18.4 months (95% confidence interval 10.4 to 19.6). Three- and 5-year survival rates in the SRC group were 33.7% and 25.3%, respectively. The overall survival rate of patients with SRC was significantly poorer than that of patients with mucinous or poorly differentiated adenocarcinoma (P < .001).

CONCLUSIONS

SRC of the colorectum is characterized by advanced stage at diagnosis with lower rates of curative resection. It tends to affect younger patients with more propensity for lymphovascular invasion.

Colorectal mucinous adenocarcinoma: the clinicopathologic features and significance of p16 and p53 expression

PURPOSE

This study was designed to examine the clinicopathologic features and p53 and p16 expressions in colorectal mucinous adenocarcinoma and colorectal signet-ring cell carcinoma.

METHODS

The clinicopathologic features of 36 patients with colorectal mucinous adenocarcinoma and colorectal signet-ring cell carcinoma were analyzed and compared with 228 patients with colorectal adenocarcinomas. The p53 and p16 expressions in the colorectal mucinous adenocarcinoma and colorectal signet-ring cell carcinoma were studied by immunohistochemistry.

RESULTS

Colorectal mucinous adenocarcinoma and colorectal signet-ring cell carcinoma accounted for 14 percent of colorectal cancer. The median age at presentation was 67 years. Family history of colorectal cancer in their first-degree relatives was seen in 14 percent of these patients. Fifty-six percent of the carcinomas were located in the proximal colorectum, most commonly in the transverse colon. Two patients had ulcerative colitis. Compared with the usual colorectal adenocarcinoma, colorectal mucinous adenocarcinoma and colorectal signet-ring cell carcinoma was found more often in proximal colorectum (P = 0.002), larger (P = 0.05), and in advanced stages (P = 0.018). Forty-four percent (n = 16) of the colorectal mucinous adenocarcinoma and colorectal signet-ring cell carcinoma showed p53 expression. All the patients with colorectal mucinous adenocarcinoma and colorectal signet-ring cell carcinoma with a positive family history of colorectal adenocarcinoma had tumors that showed p53 expression (P = 0.012). Seventy-eight percent (n = 28) of the tumors showed p16 expression. The median survival of the patients with these tumors was 23 months. The survival of these patients with colorectal mucinous adenocarcinoma and colorectal signet-ring cell carcinoma was poorer if the lesions were of advanced stages (P = 0.023) or with family history of colorectal cancer (P = 0.0015). Also, patients with colorectal mucinous adenocarcinoma and colorectal signet-ring cell carcinoma that did not express p16 and p53 had better survival than other patients (P = 0.04).

CONCLUSIONS

Colorectal mucinous adenocarcinoma and colorectal signet-ring cell carcinoma had distinctive clinicopathologic features. Tumor staging, family history of colorectal cancer, and status of p53 and p16 expressions might predict prognosis in these patients.

Primary signet-ring cell carcinoma of the colon at early stage: A case report and a review of the literature

A 67-year-old man, who had undergone surgery to resect multiple gastric cancers 4 years ago, visited our hospital for surveillance colonoscopy. Colonoscopy revealed a discolored, 7-mm in diameter, flat-elevated lesion with central depression in the transverse colon near the splenic flexure. Although the findings of endoscopy and barium enema were suggestive of submucosal invasion, the patient chose to undergo endoscopic mucosal resection. Pathological examination of the resected specimen revealed signet-ring cell carcinoma and a positive surgical margin. A second operation was performed, and no residual tumor or metastasis to lymph nodes was found in the resected specimens. Primary colorectal cancers composed of signet-ring cell carcinoma detected and treated at an early stage are extremely rare. We present a case and review the literature.

Hereditary diffuse gastric cancer: diagnosis and management

Hereditary diffuse gastric cancer (HDGC) is a familial cancer syndrome defined by germline mutation of the E-cadherin gene (CDH-1). The cumulative risk for advanced gastric cancer in HDGC is 67% in men and 83% in women by 80 years of age. Early HDGC is characterized by multiple microscopic foci of intramucosal signet-ring cell carcinoma. The time to progression of these foci appears to be variable and currently is not predictable--the carcinoma foci may remain confined to the mucosa for many years. The management options for mutation carriers include prophylactic gastrectomy or surveillance gastroscopy. The only extensive published surveillance experience used chromogastroscopy, which detected early HDGC foci not visible on white-light endoscopy. The use of new techniques such as confocal microscopy, spectroscopy, or autofluorescence may prove useful, but have not been studied in HDGC. In patients up to 20 years of age, the risk for gastric cancer is less than 1%; this risk is outweighed by the mortality and morbidity associated with total gastrectomy. It is therefore recommended that genetic testing should occur at 16 years of age and that annual surveillance chromogastroscopy also should begin at age 16 in identified CDH-1 mutation carriers. After 20 years of age, delaying prophylactic gastrectomy carries significant risk, particularly if the alternative is surveillance by white-light gastroscopy. Surveillance chromogastroscopy (Congo red/methylene blue technique) should be considered for individuals younger than 20 years and patients unwilling to undergo prophylactic gastrectomy. Sufficient evidence for an increased risk for lobular breast cancer in CDH-1 carriers exists to justify breast screening in female carriers older than 35 years of age, however, evidence is insufficient to recommend prophylactic mastectomy.

Nuclear beta-catenin expression is rare and its potential association with short survival in colorectal signet-ring cell carcinoma

Colorectal signet-ring cell carcinoma (SRCC) is a rare cancer and the prognosis is usually very poor. The biologic pathways involved in its oncogenesis are unknown. beta-catenin, a key target in the Wnt-signaling pathway, is recognized to play an important role in the carcinogenesis in conventional colorectal carcinoma. This study explores the involvement of Wnt-signaling molecules beta-catenin and cyclin D1, cell cycle regulators cyclin D3, proliferative index Ki-67, apoptotic index, and angiogenic indicator CD31 in 20 colorectal SRCC paraffin-embedded specimens. Results showed that there were 2 specimens with nuclear beta-catenin and higher expression of cyclin D1 than the remaining 18 specimens. Surprisingly, those 2 patients had a much shorter survival of 6 months than the remaining 15 patients, who had around 24 months. Moreover, all colorectal SRCC specimens had an overexpression of cyclin D1, cyclin D3, and Ki-67, as well as much more angiogenesis and apoptosis than adjacent normal epithelial tissues. The authors make the preliminary comment that nuclear beta-catenin is a rare phenomenon in colorectal SRCC, but the involvement of it may indicate a worse prognosis with shorter survival than colorectal SRCC without nuclear beta-catenin expression. Besides, overexpression of cyclin D1, cyclin D3, Ki-67, and increased angiogenesis and apoptosis may play a vital role in promoting colorectal SRCC development.

Primary signet-ring cell carcinoma mimicking segmental Crohn's colitis

Primary signet-ring cell carcinoma of the colon is a rare entity with a dismal prognosis, mainly due to a delay in diagnosis. Here, we present a case of a 30-year-old Filipino woman who presented with symptoms mimicking inflammatory bowel disease. A barium enema and colonoscopy demonstrated a stricture in the rectosigmoid region. A biopsy revealed granulomatous changes indicative of inflammatory bowel disease. Despite initial improvement of her symptoms on total parenteral nutrition and steroids, the patient relapsed several weeks later with recurrent left lower quadrant pain. A subsequent biopsy revealed poorly differentiated signet-ring cell carcinoma of the colon. She was treated surgically with a left hemi-colectomy and primary repair. A high degree of suspicion is necessary to correctly diagnose these, often young, patients with primary signet-ring cell carcinoma early and have a positive impact on survival. The literature on primary signet-ring cell carcinoma is reviewed.

A 10-year outcomes evaluation of mucinous and signet-ring cell carcinoma of the colon and rectum

PURPOSE

Most studies examining mucinous or signet-ring cell colorectal cancers are single institution reports. This study used a national cancer registry to analyze the epidemiology and survival outcomes of these two subtypes of colorectal cancer compared with adenocarcinoma tumors.

METHODS

All patients diagnosed with mucinous (n = 16,991), signet-ring cell (n = 1,522), or adenocarcinoma (n = 146,115) colorectal cancer in the Surveillance, Epidemiology, and End Results database (1991-2000) were evaluated. Analyses were performed to obtain age-adjusted incidence rates, stage at presentation, tumor grade, and five-year relative survival for each subtype.

RESULTS

Mucinous were slightly more common in females (53.4 percent). Incidence rates per 100,000 persons were: mucinous, 5.5; signet-ring cell, 0.6; and adenocarcinoma 46.6. The annual percent change during ten years was stable for mucinous, increased for signet-ring cell (4.8 percent; P < 0.05), and decreased for adenocarcinoma (-1.1 percent; P < 0.05). Fewer mucinous (18 percent) and signet-ring cell (21 percent) tumors were located in the rectum compared with adenocarcinoma (29 percent). Signet-ring cell presented at later stage (III/IV, 80.9 percent) more often than mucinous (52.8 percent) and adenocarcinoma (49.5 percent), and also had worse tumor grade (high grade: signet-ring cell, 73.5 percent; mucinous, 20.9 percent; adenocarcinoma, 17.5 percent). Relative five-year survival was worse for signet-ring cell than mucinous or adenocarcinoma.

CONCLUSIONS

We present a large population-based review of colorectal cancer subtypes by analyzing national data from the past decade. Although the incidence of colorectal adenocarcinoma is decreasing in the United States, mucinous and signet-ring cell subtypes are stable and increasing, respectively. Importantly, it seems that the signet-ring cell subtype has worse outcomes, whereas survival rates for mucinous tumors are similar to adenocarcinomas.

Germline E-cadherin mutations in hereditary diffuse gastric cancer: assessment of 42 new families and review of genetic screening criteria

BACKGROUND

Mutations in the E-cadherin (CDH1) gene are a well documented cause of hereditary diffuse gastric cancer (HDGC). Development of evidence based guidelines for CDH1 screening for HDGC have been complicated by its rarity, variable penetrance, and lack of founder mutations.

METHODS

Forty three new gastric cancer (GC) families were ascertained from multiple sources. In 42 of these families at least one gastric cancer was pathologically confirmed to be a diffuse gastric cancer (DGC); the other family had intestinal type gastric cancers. Screening of the entire coding region of the CDH1 gene and all intron/exon boundaries was performed by bi-directional sequencing.

RESULTS

Novel mutations were found in 13 of the 42 DGC families (31% overall). Twelve of these mutations occur among the 25 families with multiple cases of gastric cancer and with pathologic confirmation of diffuse gastric cancer phenotype in at least one individual under the age of 50 years. The mutations found include small insertions and deletions, splice site mutations, and three non-conservative amino acid substitutions (A298T, W409R, and R732Q). All three missense mutations conferred loss of E-cadherin function in in vitro assays. Multiple cases of breast cancers including pathologically confirmed lobular breast cancers were observed both in mutation positive and negative families.

CONCLUSION

Germline truncating CDH1 mutations are found in 48% of families with multiple cases of gastric cancer and at least one documented case of DGC in an individual under 50 years of age. We recommend that these criteria be used for selecting families for CDH1 mutational analysis.

Bacteria-induced intestinal cancer in mice with disrupted Gpx1 and Gpx2 genes

Two glutathione peroxidase (GPX) isozymes, GPX-1 and GPX-2 (GPX-GI), are the major enzymes that reduce hydroperoxides in intestinal epithelium. We have previously demonstrated that targeted disruption of both the Gpx1 and Gpx2 genes (GPX-DKO) results in a high incidence of ileocolitis in mice raised under conventional conditions, which include the harboring of Helicobacter species [non-specific-pathogen-free (non-SPF) conditions]. In this study, we have characterized GPX-DKO mice that have microflora-associated intestinal cancers, which are correlated with increased intestinal pathology/inflammation. We found that GPX-DKO mice raised under germ-free conditions have virtually no pathology or tumors. After colonizing germ-free mice with commensal microflora without any known pathogens (SPF), <9% of GPX-DKO mice develop tumors in the ileum or the colon. However, about one-fourth of GPX-DKO mice raised under non-SPF conditions from birth or transferred from SPF conditions at weaning have predominantly ileal tumors. Nearly 30% of tumors are cancerous; most are invasive adenocarcinomas and a few signet-ring cell carcinomas. On the basis of these results, we conclude that GPX-DKO mice are highly susceptible to bacteria-associated inflammation and cancer. The sensitivity exhibited in these mice suggests that peroxidative stress plays an important role in ileal and colonic pathology and inflammation, which can lead to tumorigenesis.

Clinical significance of signet ring cell rectal carcinoma

BACKGROUND AND AIMS

Signet ring cell carcinoma of the rectum (SCCR) is a rare type of rectal carcinoma. This study examined the clinical significance of SCCR.

PATIENTS AND METHODS

From our medical records we retrospectively identified 61 SCCR patients and compared their clinical data and outcomes to those of 144 consecutive patients with non-SCCR mucinous rectal adenocarcinomas (NSMR) and 2,414 consecutive patients with nonmucinous rectal adenocarcinomas (NMR).

RESULTS

. The incidence of SCCR was 1.39% of rectal cancers. Mean patient age at onset of SCCR (48.1years, range 15-80) was significantly lower than that for NSMR (57.4 years, 9-88) and NMR (62.6 years, 12-94). The proportion of late stage (TNM III+IV) tumors was significantly higher in SCCR (90%) than in NSMR (69%) and NMR (48%). There were more tumors located in the lower rectum in SCCR (46%) than in NSMR (34%) and NMR (29%). SCCR tumors were significantly larger (5.68+/-3.84 cm) than NSMR (4.27+/-1.78 cm) and NMR tumors (3.76+/-1.71 cm). A higher percentage of patients with SCCR (42.6%) received abdominoperineal resection for treatment. In tumors with TNM stage IV the rate of tumor spread via the hematogenous route was significantly lower in SCCR (18.5%) than in NSMR (43.5%) and in NMR (69%). The rate of tumor spread via seeding to the peritoneum was lower in SCCR (22.2%) than in NSMR (43.5%) but higher than in NMR (2.7%). The rate of tumor spread via the lymphatic route was higher in SCCR (44.4%) than in NSMR (26.1%) and significantly higher than in NMR (12.3%). The 1-, 2-, and 5-year overall SCCR survival rates were 73.9%, 36.3%, and 23.3% respectively, which were significantly poorer than those of NSMR and NMR. For the 28 stage III and R0 SCCR tumors the 1-, 2-, and 5-year disease-free survival rates of SCCR were 84.0%, 44.2%, and 30.3%, respectively, which are comparable with general data of stage III rectal cancer in the world.

CONCLUSION

Diffuse infiltration of signet ring cells enhances the tendency of mucinous carcinomas of the rectum in more local extension and easier lymphatic spreading but not at peritoneal seeding. Although SCCR had the poorest prognosis, this outcome may be due to the advanced tumor stage rather than histology itself.

Anatomic site distribution and clinic pathologic characteristics of colorectal cancer in young Chinese

AIM

To study the anatomic site distribution and pathologic characteristics of colorectal cancer (CRC) in young Chinese.

METHODS

A retrospective study was undertaken. Data were collected from 1 370 patients in Nan Fang Hospital from 1974 to 1999, including 309 patients younger than 40 years and 1 061 patients older than 40 years. The median age was 54 years. All patients with colorectal adenocarcinomas were diagnosed by histology and underwent surgery.

RESULTS

Overall, 22.3% (309/1370) of CRC patients were young people. The proportion of males in the young group was 57.0% vs 58.3% in the aged group (P>0.05, x² = 0.16). 24.1% of young group vs 25.1% of aged group had lesions in the proximal colon and 72.4% vs 71.2% had cancers located in distal colorectum (P>0.05, x² = 0.42). Adenocarcinoma was the most common histologic type in both groups. 71.5% of young group vs 83.4% of aged group was adenocarcinoma (P <0.01, x² = 18.09), 17.4% vs 12.0% was mucinous adenocarcinoma (P<0.05, x²=4.70) and 5.5% vs 1.1% was signet-ring cell carcinoma (P<0.01, x² = 30.20). 18.2% of young group vs 24.9% of aged group was early stage (Duke's stage A) and 81.9% vs 75.1% was advanced stage (Duke's stage B, C, D) (P <0.05, x² = 5.13). 20.9% of young group vs 11.1% of aged group was poor differentiation (P<0.01, x² = 14.75) and 59.5% vs 34.3% had lymphatic metastasis (P<0.01, x² = 53.25).

CONCLUSION

CRC of young people has no significant difference from middle-aged and old people in either gender distribution or anatomic site distribution, but the former has some clinical pathologic characteristics that are different from the latter. CRC in young people has relatively worse prognosis. The therapeutic effects depend on paying attention to these clinical pathologic characteristics and early diagnosis and early treatment.

[Risk factors for lymphatic metastasis from pT1 colorectal adenocarcinoma]

During the last 20 years, endoscopic removal of colorectal adenoma has become widely accepted as a replacement for removal by open surgery. Even colorectal adenocarcinomas are not excluded. The key question is when surgical treatment should still be preferred over endoscopic removal as the primary treatment. One good indicator is the frequency of lymph node metastasis, which should be compared with the overall risk involved in the surgical procedure itself. Histological examination allows subdivision of early colorectal adenocarcinomas into low-risk and high-risk groups. Classical parameters for a high-risk situation are lymphatic invasion, poor differentiation, and incomplete removal (R1). Additional risk factors that have recently been discussed are infiltration into the lower third of the submucosal layer (sm3) and dissociation (budding) of the tumour cells at the invasion front. Drawing on the literature and an analysis of our own patients, we demonstrate a positive correlation between these new markers and an elevated risk of the presence of lymph node metastasis.