Dysbiosis promotes recurrence of adenomatous polyps in the distal colorectum.

BACKGROUND: Colorectal polyps, which are characterized by a high recurrence rate, represent preneoplastic conditions of the intestine. Due to unclear mechanisms of pathogenesis, first-line therapies for non-hereditary recurrent colorectal polyps are limited to endoscopic resection. Although recent studies suggest a mechanistic link between intestinal dysbiosis and polyps, the exact compositions and roles of bacteria in the mucosa around the lesions, rather than feces, remain unsettled. AIM: To clarify the composition and diversity of bacteria in the mucosa surrounding or 10 cm distal to recurrent intestinal polyps. METHODS: Mucosal samples were collected from four patients consistently with adenomatous polyps (Ade), seven consistently with non-Ade (Pol), ten with current Pol but previous Ade, and six healthy individuals, and bacterial patterns were evaluated by 16S rDNA sequencing. Linear discriminant analysis and Student's t-tests were used to identify the genus-level bacteria differences between groups with different colorectal polyp phenotypes. Pearson's correlation coefficients were used to evaluate the correlation between intestinal bacteria at the genus level and clinical indicators. RESULTS: The results confirmed a decreased level of probiotics and an enrichment of pathogenic bacteria in patients with all types of polyps compared to healthy individuals. These changes were not restricted to the mucosa within 0.5 cm adjacent to the polyps, but also existed in histologically normal tissue 10 cm distal from the lesions. Significant differences in bacterial diversity were observed in the mucosa from individuals with normal conditions, Pol, and Ade. Increased abundance of Gram-negative bacteria, including Klebsiella, Plesiomonas, and Cronobacter, was observed in Pol group and Ade group, suggesting that resistance to antibiotics may be one risk factor for bacterium-related harmful environment. Meanwhile, age and gender were linked to bacteria changes, indicating the potential involvement of sex hormones. CONCLUSION: These preliminary results support intestinal dysbiosis as an important risk factor for recurrent polyps, especially adenoma. Targeting specific pathogenic bacteria may attenuate the recurrence of polyps.

Listeria monocytogenes: a promising vector for tumor immunotherapy.

Cancer receives enduring international attention due to its extremely high morbidity and mortality. Immunotherapy, which is generally expected to overcome the limits of traditional treatments, serves as a promising direction for patients with recurrent or metastatic malignancies. Bacteria-based vectors such as Listeria monocytogenes take advantage of their unique characteristics, including preferential infection of host antigen presenting cells, intracellular growth within immune cells, and intercellular dissemination, to further improve the efficacy and minimize off-target effects of tailed immune treatments. Listeria monocytogenes can reshape the tumor microenvironment to bolster the anti-tumor effects both through the enhancement of T cells activity and a decrease in the frequency and population of immunosuppressive cells. Modified Listeria monocytogenes has been employed as a tool to elicit immune responses against different tumor cells. Currently, Listeria monocytogenes vaccine alone is insufficient to treat all patients effectively, which can be addressed if combined with other treatments, such as immune checkpoint inhibitors, reactivated adoptive cell therapy, and radiotherapy. This review summarizes the recent advances in the molecular mechanisms underlying the involvement of Listeria monocytogenes vaccine in anti-tumor immunity, and discusses the most concerned issues for future research.

Hdc-expressing myeloid-derived suppressor cells promote basal-like transition and metastasis of breast cancer.

Metastases are the greatest contributors to death from breast cancer. Here, we identified a distinct subpopulation of luminal breast cancer characterized by cytokeratin 14 (CK14) expression in secondary colonies rather than primary tumors. This entity possessed a poorer prognosis compared to their CK14- counterparts. Immunohistochemical analysis showed that myeloid-derived suppressor cells (MDSCs) were recruited into the tumor microenvironment and exhibited a close spatial relationship with CK14+ cancer cells. We demonstrated that histidine decarboxylase (Hdc) is capable of labeling myeloid-biased hematopoietic stem cell/progenitor cell (HSC/HSPC) and immature myeloid cells infiltrating in tumor tissues. FACS data obtained from Hdc-CreERT2; eGFP; MMTV-PyVT female mice revealed an increased percentage of Hdc+ PMN-MDSCs in metastatic masses. Hdc+ PMN-MDSCs expressed high levels of canonical Wnts, including Wnt2, Wnt4, Wnt5a, and Wnt7b, to aberrantly activate Wnt/ß-catenin signaling in CK14+ malignant cells. ß-catenin translocated from the membrane into the cytoplasm and nucleus. Targeted ablation of Hdc+ PMN-MDSCs-derived Wnts through porcupineflox/flox and iDTR transgenic models hampered the metastatic cascade, making Hdc+ immature myeloid cells an attractive candidate for tailed immunotherapies.

Extraovarian Brenner tumor in the uterus: a case report and review of literature.

BACKGROUND: Extraovarian Brenner tumors (EOBTs) are extremely rare and can be observed incidentally in both female and male patients, raising concerns regarding the origin of Brenner tumors. CASE PRESENTATION: A 53-year-old postmenopausal woman presented with a nodular lesion in the left side of the corpus uteri, which was found at a routine health check. Macroscopically, the lesion appeared as a solid nodule with a yellowish-gray cut surface, approximately 6 cm in greatest diameter. Microscopically, the lesion consisted of well-defined epithelial nests and spindled stromal cells. Parenchymal cells expressed CK7, GATA3, CK5/6, 34ßE12, and p63. A single layer of cavity-lined cells with umbrella-like shape showed apical Uroplakin III positivity. Stromal cells were positive for SMA, ER, and PR. The final diagnosis was EOBT and the patient was followed for 2 months with no recurrence. CONCLUSIONS: We report here the third case of EOBTs in the uterus. The combination of morphologic and immunohistochemical results supported the involvement of urothelial metaplasia in the development of EOBTs. The similarities between EOBTs and Walthard nests made Müllerian epithelium an attractive candidate as the cellular origin. Changes of tissue structure or sex hormones imbalance may lead to the translocation of Müllerian remnants to distant organs, explaining the pathogenesis of EOBTs.

Synchronous multiple primary gastrointestinal cancers with CDH1 mutations: A case report.

BACKGROUND: Synchronous multiple primary cancers (SMPC) mean two or more malignant tumors occurring simultaneously and with different origins no matter what types they are or where they are located. The carcinogenesis of SMPC often involves variations of some specific genes. However, the correlation between CDH1 mutations and synchronous multiple primary gastrointestinal cancers is largely unknown. CASE SUMMARY: A 62-year-old woman had sustained abdominal pain for one week and visited our hospital. Gastrointestinal endoscopy revealed multiple small polypoid lesions in both the stomach and colorectum. Computed tomography and laboratory results were within normal limits. Pathological evaluation confirmed signet ring cell carcinoma without obvious metastatic evidence. Malignant cells showed negativity for E-cadherin and positivity for ß-catenin in the cytoplasm and nucleus. DNA sequencing performed on paraffin-embedded tissue revealed two exactly coincident alterations in CDH1, C.57T>G and C.1418A>T. CONCLUSION: This case suggests that the combination of CDH1 mutations and WNT/ß-catenin signaling activation contributes to the carcinogenesis of gastrointestinal SMPC.

Epithelioid sarcoma of the scalp: a case report and literature review.

Epithelioid sarcoma (ES) is an aggressive mesenchymal tumor exhibiting bi-directional phenotypes. According to its proclivity for different sites, ES can be subdivided into two categories: distal and proximal variants. Proximal ES often affects the truncal tissue, thighs, head, and neck. Accumulating evidence indicates that several locations in the head, including the orbital, gingival, and nasal cavities, are involved in ES. However, the underlying mechanisms of ES carcinogenesis and progression are largely unknown, including and especially the reason why the tumor cells are positive for both epithelial and mesenchymal classical markers. Thus, we wish to share a rare case of ES in the scalp and its clinical and molecular features. Only 9 cases to date have been reported. An 80-years-old man had sustained a painful swollen mass in his scalp for three months. A diagnosis of epithelioid sarcoma was established based on the combination of the histopathological and immunohistochemical findings. The tumor cells were positive for both mesenchymal (vimentin and S100) and epithelial markers (pan-cytokeratin). This case suggests that ES can be derived from the soft tissue of the scalp. The tumor cells co-expressed biomarkers of epithelial and mesenchymal cells, suggesting the mesenchymal-epithelial transition (MET) may be involved.

Analysis of epithelial-mesenchymal transition markers in the histogenesis of hepatic progenitor cell in HBV-related liver diseases.

BACKGROUND: The origin and heterogeneity of hepatic progenitor cells (HPCs) remain unclear. This study aimed to investigate the involvement of epithelial-mesenchymal transition (EMT) in the histogenesis of HPCs. METHODS: Surgical liver specimens from patients with HBV-related hepatitis and cirrhosis were investigated with double immunofluorescence labeling to detect antigens associated with HPCs and EMT. Ductular reactions were subjected to quantitative reverse transcription PCR following isolation by laser capture microdissection. Electron microscopic examination was performed to find an ultrastructural evidence of EMT. RESULTS: The number of EpCAM-positive HPCs was proportional to the disease severity. The S100A4 expression of HPCs was firstly observed in mild hepatitis and increased significantly in moderate hepatitis, but decreased in severe hepatitis and cirrhosis. The levels of MMP-2, Twist, and Snail increased in direct proportion to the number of HPCs. Some hepatocytes adjacent to portal tracts in cirrhosis showed positivity for MMP-2. Although CK7 and E-cadherin levels decreased in mild and moderate hepatitis, HPCs re-expressed both of them in severe hepatitis and cirrhosis. However, HPCs expressed neither vimentin nor αSMA. The relative mRNA expression levels of EpCAM and EMT-associated markers supported immunohistochemical results. Electron microscopic examination demonstrated the existence of intercellular junctions among HPCs, cholangiocytes, and intermediate hepatocyte-like cells. CONCLUSION: We provided preliminary evidence for the involvement of EMT in the histogenesis of HPCs from cholangiocytes in HBV-related liver diseases. HPCs may re-transdifferentiate into hepatocytes, and the differentiation direction depends, at least in part, on interactions between HPCs and the surrounding microenvironment, especially the non-resolving inflammation caused by HBV infection.

Cutaneous clear cell/signet-ring cell squamous cell carcinoma arising in the right thigh of a patient with type 2 diabetes: combined morphologic, immunohistochemical, and etiologic analysis.

BACKGROUND: The clear cell/signet-ring cell variant of cutaneous squamous cell carcinoma (cSCC) is extremely rare. Its carcinogenesis has consistently been linked to ultraviolet radiation and HPV in the literature. However, there is little definite information about the contribution of diabetes mellitus (DM) to cSCC. CASE PRESENTATION: A 78-year-old Chinese woman with type 2 DM presented with a mushroom-like lump in her right thigh. Histological findings revealed that the lesion was mainly composed of clear cells and signet-ring cells. The septa of vacuoles in cytoplasm displayed positivity for periodic acid schiff (PAS) and cytokeratins such as AE1/AE3, CK5/6, CK14, and CK19. Malignant cells did not express CK7, CK8, CK18, CK20, p16, p53, or c-erbB-2, and the Ki-67 index was less than 5 %. We further explored the etiology of clear cell/signet-ring cell cSCC using human papillomavirus (HPV) type-specific PCR and genotyping and confirmed that the patient was not infected with HPV. Nucleus positivity for p63 indicated the involvement of the p53 family in the lesion. Meanwhile, the expression of fibroblast growth factor receptor-2 (FGFR2), a downstream effector of p63, was upregulated in tumor cells. CONCLUSIONS: This study provides the first report on the clear cell/signet-ring cell variant of cSCC found in the right thigh of a patient with type 2 DM. Metabolic imbalance in addition to conventional pathogens such as UV and HPV may contribute to the development of the lesion via p63/FGFR2 axis.