Absence of a pancreatic microbiome in intraductal papillary mucinous neoplasm.

OBJECTIVE: This study aims to validate the existence of a microbiome within intraductal papillary mucinous neoplasm (IPMN) that can be differentiated from the taxonomically diverse DNA background of next-generation sequencing procedures. DESIGN: We generated 16S rRNA amplicon sequencing data to analyse 338 cyst fluid samples from 190 patients and 19 negative controls, the latter collected directly from sterile syringes in the operating room. A subset of samples (n=20) and blanks (n=5) were spiked with known concentrations of bacterial cells alien to the human microbiome to infer absolute abundances of microbial traces. All cyst fluid samples were obtained intraoperatively and included IPMNs with various degrees of dysplasia as well as other cystic neoplasms. Follow-up culturing experiments were conducted to assess bacterial growth for microbiologically significant signals. RESULTS: Microbiome signatures of cyst fluid samples were inseparable from those of negative controls, with no difference in taxonomic diversity, and microbial community composition. In a patient subgroup that had recently undergone invasive procedures, a bacterial signal was evident. This outlier signal was not characterised by higher taxonomic diversity but by an increased dominance index of a gut-associated microbe, leading to lower taxonomic evenness compared with the background signal. CONCLUSION: The 'microbiome' of IPMNs and other pancreatic cystic neoplasms does not deviate from the background signature of negative controls, supporting the concept of a sterile environment. Outlier signals may appear in a small fraction of patients following recent invasive endoscopic procedures. No associations between microbial patterns and clinical or cyst parameters were apparent.

Multiresistent opportunistic talaromycosis in a patient with ovarian cancer.

BACKGROUND: Talaromycosis (penicillinosis) is multiresistent opportunistic mycosis. The infection can be inapparent and it can simmulate malignant tumor dissemination in some patients. CASE: We present a case of 33-years-old patient with mucinous adenocarcinoma of left ovary, initially FIGO IIC. The patient had had hysterectomy, bilateral adnexectomy, omentectomy and port-site metastasis extirpation. Six cycles of 1st chemother-apy paclitaxel and carboplatin had been administered to patient follow-ing the surgery. Positron emission tomography / computed tomography (PET/CT) scan after the treatment, had shown metabolic activity infiltrat-ing both lung apexes, supposedly with no dis-ease correlation, and hypermetabolic foci in spleen, suspicious of be-ing metastases. Pa-cient showed no clinical symp-toms, nor markers of inflammation elevation. Initially elevated serum tumor markers CA125 and CA72-4 had decreased after the treatment. Bronchoalveolar lavage cytology described presence of inflammatory infiltration with fungiform-ing hyphae - most probably an aspergillosis. Mannan and galactomannan serology was negative. In regard to splenectomy plans, treatment with voriconazol was initiated empirically. Result of fungi cultivation out of bronchoalveolar lavage was finalized later, show-ing sporadic presence o Penicillium sp. with resistance to antimycotic treatment except for amphotericin B. Liposomal amphotericin B treatment was administered in two cures, 28 days in total. Immunomodulatory treatment of secondary cellular immunodeficiency and vaccination against encapsulated bacteria was given to the patient. Splenectomy was performed 6 months after the end of chemother-apy treatment. Histopathology showed chronic granulomatous inflammation without mycotic hyphae, with no evidence of tumor cells. After the splenectomy, patient was treated by surgical incision and drainage and by klindamycin for intraabdominal abscess in left hypogastric area. CONCLUSION: Patient is under follow up by oncologist, immunologist and gynecologist 12 months after the splenectomy, she is surveilled by PET/CT and serum tumor markers. Talaromycosis can be clinically inapparent in spite of its dissemination. It can be present in diffuse, granulomatous and mixed form. Therapeutic agent is sometimes limited to amphotericin B due to its resistence. Liposomal form of amphotericin B is recommended regard-ing its pharmacokinetic properties. In case of dissemination, administration period of more than 14 days is recommended, even in inapparent form. Immunomodulatory treatment is recommended due to opportunistic infection.

Bacterial biofilms as a potential contributor to mucinous colorectal cancer formation.

A prominent mucinous phenotype is observed in 10-15% of all colorectal cancers (CRCs). They are associated with a proximal location, and more commonly observed among tumors with mismatch repair defects and a promoter CpG methylator phenotype. However, none of these features has been clearly linked mechanistically to this mucinous subtype. Here, we propose that bacterial biofilms could represent a currently unappreciated contributor to mucinous CRC formation. The colonic microbiome and biofilms in particular, are emerging as important factors in tumor initiation and progression. Intriguingly, biofilms preferentially accompany proximal tumors, suggesting that there may be a direct mechanistic link with mucinous CRCs.

Helicobacter pylori is undetectable in intraductal papillary mucinous neoplasm.

BACKGROUND: About half of the world population is infected with Helicobacter pylori (H. pylori), a bacterium associated with gastric cancer and considered to be a risk factor for pancreatic ductal adenocarcinoma. Whether the bacterium is associated with intraductal papillary mucinous neoplasm, believed to be a precursor of pancreatic ductal adenocarcinoma, is unknown. The aim of this study was to investigate the presence of H. pylori DNA in tissue sections of intraductal papillary mucinous neoplasm. METHODS: The presence of H. pylori DNA was tested in a retrospective controlled study of formalin-fixed, paraffin-embedded pancreatic tissues from 24 patients who underwent surgery for intraductal papillary mucinous neoplasm. Histologically normal tissues surrounding neoplasms were used as control. H. pylori DNA was evaluated after deparaffinization, DNA extraction, and purification, and results were evaluated statistically. RESULTS: Samples were collected from 13 males and 11 females with mean age 59 years (range 44-77), and consisted of 19 cases of main-duct and three cases of branched-duct intraductal papillary mucinous neoplasm. Two patients were diagnosed with pancreatic cancer and main-duct intraductal papillary mucinous neoplasm. H. pylori DNA was not detected either in intraductal papillary mucinous neoplasm tissue, or in surrounding normal tissue. CONCLUSIONS: Although H. pylori has been implicated in pancreatic ductal adenocarcinoma, it may not play a key role in the development of intraductal papillary mucinous neoplasm.

Antibiotic treatment decreases microbial burden associated with pseudomyxoma peritonei and affects ß-catenin distribution.

PURPOSE: Pseudomyxoma peritonei is an understudied cancer in which an appendiceal neoplasm invades the peritoneum and forms tumor foci on abdominal organs. Previous studies have shown that bacteria reside within pseudomyxoma peritonei tumors and mucin. Thus, we sought to analyze the effect of antibiotics on bacterial density and ß-catenin expression within pseudomyxoma peritonei samples. EXPERIMENTAL DESIGN: The study included 48 patients: 19 with disseminated peritoneal adenomucinosis (DPAM) and 29 with peritoneal mucinous carcinomatosis (PMCA). Fourteen patients were given antibiotics (30 mg lansoprazole, 1 g amoxicillin, and 500 mg clarithromycin) twice a day for 14 days. One week after completion of therapy, surgery was conducted and specimens were harvested for pathology, bacterial culture, ISH, and immunohistochemistry. RESULTS: ISH showed the presence of bacteria in 83% of the patient samples, with a higher Helicobacter pylori density observed in PMCA versus DPAM. PMCA patients treated with antibiotics had a significantly lower bacterial density and decreased ß-catenin levels in the cytoplasm, the cell nuclei, and mucin-associated cells. Although not significant, similar trends were observed in DPAM patients. Cell membrane ß-catenin was significantly increased in both DPAM and PMCA patients receiving antibiotics. CONCLUSIONS: Bacteria play an important role in pseudomyxoma peritonei. Antibiotic treatment improved the histopathology of tissue, particularly in PMCA patients. In PMCA, antibiotics decreased bacterial density and were associated with a significant ß-catenin decrease in the cytoplasm, cell nuclei, and mucin along with a small membrane increase. These results suggest that antibiotics offer potential protection against cell detachment, cellular invasion, and metastasis.

Clostridium septicum sepsis and colorectal cancer - a reminder.

BACKGROUND: Spontaneous clostridium septicum infections are rare and are associated with a high mortality. Association of clostridium infection with colorectal malignancies have been previously reported and most cases are described in tumours of the ascending colon. We report our experience of clostridium septicum infection in the presence of tumour perforation in a series of two patients as a reminder of its association with sepsis in the presence of colorectal malignancy. CASE PRESENTATION: We isolated clostridium septicum infection in a series of two patients admitted as emergencies. One patient was found to have a perforated caecal tumour intraoperatively whilst the other had a perforated rectal tumour. The clinical outcome and management of each case are reported and underlying reasons for variations in outcome are discussed. CONCLUSION: Although uncommon, the possibility of clostridium septicum sepsis should be borne in mind in patients who present with underlying malignancy and have sepsis. The cumulative effect of sepsis and malignant perforation is associated with a high morbidity and mortality. Awareness and early diagnosis of clostridium septicum may improve the prognosis of what is usually regarded as a fatal infection.

Pseudomyxoma peritonei: is disease progression related to microbial agents? A study of bacteria, MUC2 AND MUC5AC expression in disseminated peritoneal adenomucinosis and peritoneal mucinous carcinomatosis.

BACKGROUND AND AIMS: Pseudomyxoma peritonei (PMP) is characterized by peritoneal tumors arising from a perforated appendiceal adenoma or adenocarcinoma, but associated entry of enteric bacteria in the peritoneum has not been considered as a cofactor. Because Gram-negative organisms can upregulate MUC2 mucin gene expression, we determined whether bacteria were detectable in PMP tissues. METHODS: In situ hybridization was performed on resection specimens from five control subjects with noninflamed, nonperforated, non-neoplastic appendix and 16 patients with PMP [six with disseminated peritoneal adenomucinosis (DPAM) and 10 with peritoneal mucinous carcinomatosis (PMCA)]. Specific probes were designed to recognize: (1) 16S rRNA common to multiple bacteria or specific to H. pylori; (2) H. pylori cagA virulence gene; or (3) MUC2 or MUC5AC apomucins. Specimens from one patient with PMCA were examined by ultrastructural immunohistochemistry. Bacterial density and apomucin expression were determined in four histopathological compartments (epithelia, inflammatory cells, stroma, and free mucus). RESULTS: Enteric bacteria were detected in all specimens. Bacterial density and MUC2 expression were significantly (p < 0.05) higher in PMCA than in DPAM and controls and were highest in free mucin. MUC2 was also expressed in dysplastic epithelia and in associated inflammatory cells. MUC2 expression was significantly correlated with bacterial density. CONCLUSIONS: Multiple enteric bacteria are present in PMP, and bacterial density and MUC2 expression is highest in the malignant form of PMP. Based on these observations, we propose that the bacteria observed in PMP may play a role in the mucinous ascites and perhaps promote carcinogenesis.

[Expression of hMSH2 and hMLH1 in stomach cancer and their correlation with Helicobacter pylori infection].

BACKGROUND & OBJECTIVE: The carcinogenesis of gastric carcinoma is related to many factors. Helicobacter pylori (HP) infection is one of the factors causing gastric carcinoma, but the exact molecular mechanism is not clear. Mismatch repair genes are important in keeping the accuracy of DNA replication. They are associated with carcinogenesis of alimentary canal. In order to investigate the role of hMSH2 and hMLH1 in stomach cancer and the possible mechanism of carcinogenesis caused by HP infection, we tested cancer tissue, surrounding mucosa and chronic superficial gastritic mucosa with and without HP infection. METHODS: HP infection was determined with quick-ureolytase method. Immunohistochemistry staining was used to exam the expression of hMSH2 and hMLH1 in tumor tissue and their surrounding mucosa and gastric mucosa. Chi-square was used for statistic analysis. RESULTS: The positive rate (67.1%) of hMSH2 expression in cancer tissue was significantly higher than those of surrounding mucosa (35.5%) and gastritic mucosa (42.1%) (P< 0.05); the positive rate (81.1%) of hMSH2 expression in poor differentiation group was significantly higher than those in well middle differentiation group (54.5%) and mucoid carcinoma group (54.5%) (P< 0.05), but there was no significant difference between the latter two groups. There was no significant difference among the positive rates of hMLH1 expression in cancer tissue (81.6%), in surrounding mucosa (90.8%), and in gastritic mucosa (89.5%) (P>0.05). The positive rate (47.1%) of hMLH1 expression in mucoid carcinoma group was significantly higher than those in well middle differentiation group (81.8%) and poor differentiation group (97.3%) (P< 0.05), but there was no significant difference between the latter two groups (P>0.05). In cancer tissue, the positive rate (56.8%) of hMSH2 expression in HP infection group was significantly lower than that without HP infection group (81.3%) (P< 0.05); the positive rates of hMLH1 expression was 77.2% in HP infection group and 87.5% in without HP infection group, but there was no significant difference between two groups (P >0.05). In surrounding mucosa, the positive rate of hMSH2 expression was 29.5% in HP infection group and 43.8% in without HP infection group, as well as those of hMLH1 were 86.4% and 96.9%, there were no significant differences between the groups. In gastritic mucosa, the positive rate of hMSH2 expression was 38.5% in HP infection group and 50.5% in HP-negative group, as well as those of hMLH1 were 88.5% and 91.7%; there was no significant difference between the groups. CONCLUSION: The expression of hMSH2 is associated with carcinogenesis of stomach cancer, and its high expression may be a potential marker of stomach cancer; HP infection inducing low expression of hMSH2 and hMLH1 may be one of molecular mechanisms by which HP infection leads to stomach cancer.

Carcinoma in the gastric pouch years after vertical banded gastroplasty.

A 67-year-old lady presented with anemia and weight loss 15 years after vertical banded gastroplasty. The cancer was confined to the pouch, which is suggestive of a relationship to the anti-obesity surgery. A brief review with possible contributing factors is presented.

Epstein-Barr virus and gastric remnant cancer.

BACKGROUND: Carcinoma arising in the gastric remnant many years after partial gastrectomy for benign disease, referred to as gastric remnant cancer (GRC) is well known, and many causal explanations have been proposed. Elsewhere, Epstein-Barr virus (EBV) involvement has been demonstrated in a small but significant fraction of gastric cancers, and evidence has been presented suggesting that, in positive cases, EBV may have played a causal role. The present report is concerned with EBV involvement in GRC in particular. METHODS: Paraffin sections from 48 cases of GRC were studied by EBER-1 in situ hybridization. RESULTS: Thirteen cases (27.1%) showed uniform hybridized signals restricted to the carcinoma cells in contrast to no hybridization in the normal mucosa, intestinal metaplasia, or hyperplastic epithelium. The prevalence of EBV involvement in GRC was significantly higher (P < 0.0001) than in gastric carcinomas from 1825 nonremnant cases; the difference remained highly significant even when the comparison was restricted to nonremnant cancers arising in the cardia and middle stomach, for which EBV-positive rates were highest. CONCLUSION: The EBV may play an important role in the carcinogenesis of GRC.