Spontaneous regression of pancreatic cancer: A case report and literature review

The Spontaneous Regression of Primary Gastrointestinal Malignancies: An Observational Review

The spontaneous regression or remission (SR) of cancer, often described as the partial or complete disappearance of a malignant tumor in the absence of all medical treatment and therapy, is a well-documented phenomenon. With efforts ongoing to establish cancer treatments that limit undesirable outcomes and adverse effects, these uncommon occurrences of SR carry significant implications for novel therapies and warrant further investigation. While several case studies have reported instances of SR in gastrointestinal (GI) malignancies, a comprehensive review of previous manifestations of SR in the GI tract remains lacking. The inclusion criteria for the rare phenomenon are also in need of an appropriate update that takes recent scientific advancements and emerging new medical technologies into account. Our analysis of 390 cases of SR in the GI tract focuses primarily on neoplasms of the hepatobiliary system and proposes an updated version of the older inclusion criteria for spontaneous regression.

microRNA-26a represses pancreatic cancer cell malignant behaviors by targeting E2F7

Dysregulation of microRNAs (miRNAs) exerts key roles in the development of pancreatic cancer (PCa). miR-26a is reportedly a tumor suppressor in cancers. However, whether miR-26a modulates PCa progression is poorly understood. Here, we found that miR-26a was down-regulated in PCa. Overexpressed miR-26a suppressed PCa cell proliferation, colony formation, and tumor stem cell properties. Mechanically, the transcription factor E2F7 is a downstream target of miR-26a. miR-26a decreased E2F7 expression through binding to the 3'-untranslated region (UTR) of E2F7. Decreased miR-26a in PCa tissues was inversely correlated with E2F7. The inhibitory effects of miR-26a in PCa were reversed by E2F7 overexpression. Consistently, the knockout of E2F7 further significantly inhibited the growth of PCa cells combined with miR-26a overexpression. Further study revealed that E2F7 bound the promoter of vascular endothelial growth factor A (VEGFA), a key factor in angiogenesis, and transcriptionally activated the expression of VEGFA. miR-26a overexpression attenuated the effects of E2F7 on VEGFA promotion. Our results uncovered the novel function of miR-26a/E2F7/VEGFA in PCa, making miR-26a a possible target for PCa treatment.

Systematic review and meta-analysis of gemcitabine-based chemotherapy after FOLFIRINOX in advanced pancreatic cancer

Background

There are no randomized data to guide treatment decisions for patients with advanced pancreatic adenocarcinoma following first-line FOLFIRINOX. We performed a systematic review and meta-analysis of studies using gemcitabine-based chemotherapy after FOLFIRINOX to assess treatment efficacy and toxicity.

Methods

We included studies published between 2011 and 2018 that evaluated the efficacy and toxicity of gemcitabine-based chemotherapy after FOLFIRINOX in patients with advanced pancreatic adenocarcinoma. We searched PubMed, Embase, Scopus, and Web of Science. Primary outcomes were objective response rate (ORR), disease control rate (DCR), any grade 3/4 toxicity rate, and progression-free survival (PFS). We used the random-effects model to generate pooled estimates for proportions.

Results

Sixteen studies met the eligibility criteria. Overall, ORR was 10.8%, DCR was 41.1%, and any grade 3/4 toxicity rate was 28.6%. In subgroup analyses, gemcitabine plus nab-paclitaxel was associated with superior ORR (14.4 versus 8.4%; p = 0.038) and DCR (53.5 versus 30.5%; p < 0.001) compared with single-agent gemcitabine. Median PFS ranged from 1.9 to 6.4 months and numerically favored gemcitabine plus nab-paclitaxel.

Conclusions

Our study suggests gemcitabine-based chemotherapy likely outperforms best supportive care after FOLFIRINOX in advanced pancreatic cancer. Also, gemcitabine plus nab-paclitaxel seems to be more active than single-agent gemcitabine (CRD42018100421).

Spatial and phenotypic characterization of pancreatic cancer-associated fibroblasts after neoadjuvant treatment

Pancreatic ductal adenocarcinoma (PC) is characterized by a highly fibrotic desmoplastic stroma. Subtypes of cancer-associated fibroblasts (CAFs) have been identified in chemotherapy-naïve PC (CTN-PC), but their precise functions are still unclear. Our knowledge regarding the properties of CAFs in the regressive stroma after neoadjuvant treatment (NAT) of PC (NAT-PC) is particularly limited. We aimed to examine the marker phenotypic properties of CAFs in the regressive stroma of PC. Surgical specimens from patients with CTN-PC (n=10) and NAT-PC (n=10) were included. Juxtatumoural, peripheral, lobular, septal, peripancreatic, and regressive stromal compartments were manually outlined using digital imaging analysis (DIA) for area quantification. The compartment-specific expression of CD271, cytoglobin, DOG-1, miR-21, osteonectin, PDGF-Rβ, and tenascin C was evaluated by immunohistochemistry or in situ hybridization, using manual scoring and automated DIA. The area fraction of the regressive stroma was significantly higher in NAT-PC than in CTN-PC (P=0.0002). CD271 (P<0.01), cytoglobin (P<0.05), DOG1 (P<0.05), miR-21 (P<0.05), and tenascin C (P<0.05) exhibited significant differences in their expression profiles between the juxtatumoural compared to the peripheral and regressive stroma. PDGF-Rβ expression was significantly higher in juxtatumoural than in peripheral CAFs (P<0.05). Our data provide further support of the concept of stromal heterogeneity and phenotypic different CAF subtypes in PC. CAFs in the regressive stroma of NAT-PC show a marker phenotype similar to some (namely, peripheral) and different from other (namely, juxtatumoural) previously defined CAF subtypes. It may be hypothesized that phenotypic CAF subtypes, at least in part, also may share functional properties. Studies examining the precise functional characteristics of CAF subtypes in PC are needed.

Reversion of tumor hepatocytes to normal hepatocytes during liver tumor regression in an oncogene-expressing transgenic zebrafish model

Tumors are frequently dependent on primary oncogenes to maintain their malignant properties (known as 'oncogene addiction'). We have previously established several inducible hepatocellular carcinoma (HCC) models in zebrafish by transgenic expression of an oncogene. These tumor models are strongly oncogene addicted, as the induced and histologically proven liver tumors regress after suppression of oncogene expression by removal of a chemical inducer. However, the question of whether the liver tumor cells are eliminated or revert to normal cells remains unanswered. In the present study, we generated a novel Cre/loxP transgenic zebrafish line, Tg(fabp10: loxP-EGFP-stop-loxP-DsRed; TRE: CreERT2) (abbreviated to CreER), in order to trace tumor cell lineage during tumor regression after crossing with the xmrk (activated EGFR homolog) oncogene transgenic line, Tg(fabp10: rtTA; TRE: xmrk; krt4: EGFP) We found that, during HCC regression, restored normal liver contained both reverted tumor hepatocytes (RFP+) and newly differentiated hepatocytes (GFP+). RNA sequencing (RNA-seq) analyses of the RFP+ and GFP+ hepatocyte populations after tumor regression confirmed the conversion of tumor cells to normal hepatocytes, as most of the genes and pathways that were deregulated in the tumor stages were found to have normal regulation in the tumor-reverted hepatocytes. Thus, our lineage-tracing studies demonstrated the potential for transformed tumor cells to revert to normal cells after suppression of expression of a primary oncogene. This observation may provide a basis for the development of a therapeutic approach targeting addicted oncogenes or oncogenic pathways.

LncRNA-135528 inhibits tumor progression by up-regulating CXCL10 through the JAK/STAT pathway

Spontaneous tumor regression can be observed in many tumors, however, studies related to the altered expression of lncRNA in spontaneous glioma regression are limited, and the potential contributions of lncRNAs to spontaneous glioma regression remain unknown. To investigate the biological roles of lncRNA-135528 in spontaneous glioma regression. The cDNA fragment of lncRNA-135528 was obtained by rapid-amplification of cDNA ends (RACE) technology and cloned into the plvx-mcmv-zsgreen-puro vector. Additionally, we stably silenced or overexpressed lncRNA-135528 in G422 cells by transfecting with siRNA against lncRNA-135528 or lncRNA-135528 overexpression plasmid. Then, we examined lncRNA-135528 overexpressing and lncRNA-135528 silencing on glioma cells and its effects on CXCL10 and JAK/STAT pathways. The main findings indicated that lncRNA-135528 promoted glioma cell apoptosis, inhibited cell proliferation and arrested cell cycle progression; the up-regulation of lncRNA135528 led to significantly increased CXCL10 levels and the differential expression of mRNA associated with JAK/STAT pathway in glioma cells. lncRNA-135528 can inhibit tumor progression by up-regulating CXCL10 through the JAK/STAT pathway.

Spontaneous regression of pancreatic cancer with liver metastases

Spontaneous cancer regression is a rare event, scarcely reported among gastrointestinal malignancies. Pancreatic adenocarcinoma regression has been documented in five previous cases, none of which included liver metastases, and the mechanism by which this occurs is not known. A 56-year-old woman with history of discoid lupus, homocysteinemia and peripheral vascular disease was diagnosed with stage IV pancreatic ductal adenocarcinoma (PDA) metastatic to the liver. She received palliative chemotherapy with 5-fluorouracil, leucovorin, irinotecan and oxaliplatin (FOLFIRINOX) for 6 months, complicated by mucositis, diarrhoea, vomiting and two Clostridium difficile colitis episodes. Cancer initially responded to chemotherapy. However, due to substantial toxicities, she decided to discontinue cytotoxic chemotherapy and focus on palliation alone. Thereafter, CT and carbohydrate antigen (CA) 19-9 showed further response and ultimately complete cancer regression that has persisted for 33 months after cessation of chemotherapy. This is the first report in the English literature showing spontaneous regression of a PDA with liver metastases. Two possible mechanisms are proposed: antitumoral autoimmunity and tumour hypoxia related to vascular disease.