A case of rectal neuroendocrine carcinoma in a patient with long-standing ulcerative colitis involving alterations of the p16-Rb pathway

Mixed neuroendocrine-non-neuroendocrine neoplasm of the colon treated with laparoscopic resection and adjuvant chemotherapy: a case report

Mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) of the colon is rare with a poor prognosis. Since the first description of a mixed neoplasm 100 years ago, the nomenclature has evolved, most recently with the 2022 World Health Organization (WHO) classification system. We describe our experience of a case of locoregionally advanced MiNEN of the descending colon treated with curative laparoscopic resection and adjuvant chemotherapy. The patient is a 72 year old woman who presented with haematochezia. Initial clinical diagnosis was poorly differentiated adenocarcinoma of the descending colon, cT2N0M0, cStage I. Laparoscopic partial colectomy of the descending colon with D3 lymph node dissection and intracorporeal overlap anastomosis was performed. The pathological diagnosis however, returned mixed adenocarcinoma-neuroendocrine carcinoma (MANEC) of the descending colon, pT4aN1bM0, pStage IIIB, a subgroup of MiNEN: 70% was neuroendocrine carcinoma (NEC), whilst poorly differentiated mucinous carcinoma constituted 30% of the tumour. She completed 4 courses of irinotecan plus cisplatin (IP) adjuvant chemotherapy and is currently recurrence-free at postoperative year 2. The clinical course of MiNEN depends on the biology of the two components, both of which must be pathologically characterised. Even quantitatively discrete components should be carefully subtyped as their prognostic relevance is undetermined.

Identification of human papillomavirus and Rb/E2F pathway genomic alterations in mixed adeno-neuroendocrine carcinoma

OBJECTIVE

To investigate the molecular characteristics of Rb/E2F in mixed adeno-neuroendocrine carcinoma (MANEC).

MATERIALS AND METHODS

The clinicopathological features of MANEC were analyzed. The protein expressions of Rb, p16, and p53 were detected by the immunohistochemical method. The infection status of high-risk human papillomavirus (HR-HPV) was evaluated by in situ hybridization (ISH) and the gene chip method.

RESULTS

Thirteen cases of MANEC were divided into four molecular patterns according to Rb protein expression and HPV status. Group 1: A total of eight of the 13 cases showed positive Rb protein expression and lack of HR-HPV expression (8/13, 62%). Rb protein expression with p16 protein deletion and p53 protein abnormal expression was unique to NEC. Group 2: three cases (3/13, 23%) with negative Rb protein expression and lack of HR-HPV expression. Group 3: There was one case (1/13, 8%) with positive expression of Rb protein accompanied by HR-HPV. Group 4: There was one case of Rb protein loss with an HR-HPV-positive status.

CONCLUSIONS

HR-HPV and Rb/p16/p53 pathway can be associated in MANEC pathogenesis, which provides the research basis for personalized treatment of MANEC.

Neuroendocrine carcinoma associated with chronic ulcerative colitis: a case report and review of the literature

Adenocarcinoma is a common histological type of ulcerative colitis-associated cancer (UCAC), whereas neuroendocrine carcinoma (NEC) is extremely rare. UCAC is generally diagnosed at an advanced stage, even with regular surveillance colonoscopy. A 41-year-old man with a 17-year history of UC began receiving surveillance colonoscopy at the age of 37 years; 2 years later, dysplasia was detected in the sigmoid colon, and he underwent colonoscopy every 3 to 6 months. Approximately 1.5 years thereafter, a flat adenocarcinoma lesion occurred in the rectum. Flat lesions with high-grade dysplasia were found in the sigmoid colon and surrounding area. The patient underwent laparoscopic total proctocolectomy and ileal pouch-anal anastomosis with ileostomy. Adenocarcinoma was diagnosed in the sigmoid colon and NEC in the rectum. One year postoperation, recurrence or metastasis was not evident. Regular surveillance colonoscopy is important in patients with long-term UC. A histological examination of UCAC might demonstrate NEC.

Mixed adenoneuroendocrine carcinoma (MANEC) of the lower gastrointestinal tract: A systematic review with Bayesian hierarchical survival analysis

BACKGROUND

Mixed adeno-neuroendocrine carcinomas (MANEC) are a subgroup of mixed neuroendocrine non-neuroendocrine neoplasms (MiNEN) described as mixed neoplasms containing dual neuroendocrine and non-neuroendocrine components. The aim of this study was to appraise the prevalence of MANEC in the lower gastrointestinal (GI) tract and provide reliable estimates of survival.

METHOD

A systematic review was undertaken in accordance with PRISMA guidelines using PubMed, Embase, Cochrane Library of Systematic Review, Web of Science, and Scopus databases, and a Bayesian hierarchical survival pooled analysis was performed.

RESULTS

Of 182 unique records identified, 71 studies reporting on 752 patients met the inclusion criteria. Mean age was 64.2 ± 13.6, with a male-to-female ratio of 1.25. Overall, 60.3% of MANEC were located in the appendix, 29.3% in the colon, and 10.4% in the anorectum. More than a quarter (29%) of patients had stage IV disease at diagnosis, with higher prevalence in appendiceal than colonic and anorectal primaries. More than 80% had a high-grade (G3) endocrine component. Of the 152 patients followed up for a median of 20 months (interquartile range limits, 16.5-32), median overall survival was 12.3 months (95% credible interval [95%CrI], 11.3-13.7), with a 1.12 [95%CrI, 0.67-1.83] age-adjusted hazard ratio between metastatic and non-metastatic MANEC. Stage IV disease at diagnosis was more prognostically unfavorable in cases of colonic compared to anorectal origin.

CONCLUSION

MANEC is a clinically aggressive pathological entity. The results of this study provide new insights for the understanding of tumor location within the lower GI tract and its prognosis in terms of overall survival.

NIR promotes progression of colorectal cancer through regulating RB

NIR, a novel INHAT, negatively regulates the transcription activity of tumor repressor p53. However, if NIR functions in the tumorigenesis dependent on the regulation of p53 remains unknown. Here, we report that NIR promotes progression of colorectal cancer (CRC) through regulating RB function. Firstly, we found that NIR expression is upregulated in the human CRC tissues and significantly associated with the poor outcome of the patients. Sequence alignment shows that NIR contains an RB-binding motif LxCxE in its INHAT-2 domain. We demonstrate that NIR interacts with RB via INHAT-2 in CRC cells and promotes RB degradation through proteasome-mediated pathway. Further, either full-length GFP-NIR or GFP-NIR-INHAT2 facilitates poly-ubiquitination of RB. In addition, NIR inhibits RB acetylation by INHAT-2, suggesting NIR might promote RB degradation through inhibiting RB acetylation. Importantly, endogenous NIR is downregulated upon DNA damage, which is consistent with the upregulation of total level and acetylation of RB. We further show that Flag-NIR inhibits DNA damage-induced RB acetylation. Thus, downregulation of NIR might contribute to maintain the cellular homeostasis under DNA damage. Consequently, depletion of NIR inhibits cell proliferation and tumor growth in mouse xenografts. Taken together, we demonstrate that NIR promotes CRC progression partially through inhibiting RB acetylation and promoting RB degradation. Targeting NIR may provide a potential therapeutic strategy for NIR-upregulated CRC patients.

Solid Pseudopapillary Neoplasm of the Pancreas with High-Grade Malignant Transformation Involving p16-RB Pathway Alterations

Solid pseudopapillary neoplasm (SPN) of the pancreas has generally been regarded as a low-grade malignant tumour that preferentially develops in young women and can have a good prognosis with surgery. Among the few patients who have died from metastatic SPN are mostly those whose tumours harbour an undifferentiated component characterized by diffuse sheets of cells with increased nuclear atypia and proliferative index. We herein report a case of an aggressive, fatal, solid pseudopapillary neoplasm (SPN) of the pancreas in a 63-year-old woman complaining of epigastric pain. Despite having undergone surgical resection for a 10 cm pancreatic mass and multiple liver metastases, the patient later died due to uncontrollable metastases 36 months after the initial surgery. Histological examination showed that the tumour displayed unusual high-grade malignant features, showing diffuse sheets of cells with increased nuclear atypia and proliferative activity, along with conventional low-grade malignant features. The tumour was subsequently recognized as an SPN with foci of high-grade malignant transformation according to the 2010 World Health Organization classification. Immunohistochemical studies revealed that p16-RB pathway alterations contributed to the high-grade malignant transformation. The present case report suggests the necessity for developing diagnostic and treatment methods targeting p16 and RB for high-grade variants of SPN.