RESUMEN
BACKGROUND: Cholangiocarcinoma is the most common malignancy of the biliary tree and has a poor prognosis. Adenocarcinoma is the most common pathological type of cholangiocarcinomas, but rare squamous, adenosquamous, and mucinous variants have been reported without adequate clinical data. CASE SUMMARY: This report describes a rare case of primary squamous cell carcinoma (SCC) of the intrahepatic bile duct. The patient was admitted with a tumor in the hepatic caudate lobe with no obvious clinical symptoms. Examination revealed hepatitis B surface antigen positivity, a slight increase in alfa-fetoprotein to 16.34 ng/mL, and an irregular slightly heterogeneous enhancing lesion in the hepatic caudate lobe, which was initially thought to be hepatocellular carcinoma. Laparoscopic resection was performed, and the final pathology suggested a rare primary SCC of the intrahepatic bile duct. Immunohistochemistry indicated positivity for villin, partial positivity for p63, and negativity for hepatocyte, CK7, CK8, CK19, and CK20. The Ki-67 index was approximately 60%. The patient received six cycles of Tegio chemotherapy. A new lesion was detected in the liver after 15 months. The surgery was performed, and the patient was followed-up at a local hospital. To date, no new lesions have been observed. CONCLUSION: Surgery is the first choice for resectable lesions, and combined chemotherapy based on pathology is essential for increasing overall survival.
RESUMEN
Exosomes contribute substantially to the communication between tumor cells and normal cells. Benefiting from the stable structure, circular RNAs (circRNAs) are believed to serve an important function in exosome-mediated intercellular communication. Here, we focused on circRNAs enriched in starvation-stressed hepatocytic exosomes and further investigated their function and mechanism in hepatocellular carcinoma (HCC) progression. Differentially expressed circRNAs in exosomes were identified by RNA sequencing, and circTGFBR2 was identified and chosen for further study. The molecular mechanism of circTGFBR2 in HCC was demonstrated by RNA pulldown, RIP, dual-luciferase reporter assays, rescue experiments and tumor xenograft assay both in vitro and vivo. We confirmed exosomes with enriched circTGFBR2 led to an upregulated resistance of HCC cells to starvation stress. Mechanistically, circTGFBR2 delivered into HCC cells via exosomes serves as a competing endogenous RNA by binding miR-205-5p to facilitate ATG5 expression and enhance autophagy in HCC cells, resulting in resistance to starvation. Thus, we revealed that circTGFBR2 is a novel tumor promoter circRNA in hepatocytic exosomes and promotes HCC progression by enhancing ATG5-mediated protective autophagy via the circTGFBR2/miR-205-5p/ATG5 axis, which may be a potential therapeutic target for HCC.