Cribriform morular thyroid carcinoma (CMTC) has been included within the group of thyroid tumors of uncertain histogenesis in the recent World Health Organization classification of endocrine tumors. Most CMTCs occur in young euthyroid women with multiple (and bilateral) thyroid nodules in cases associated with familial adenomatous polyposis (FAP) or as single nodules in sporadic cases. CMTC generally behaves indolently, while aggressiveness and mortality are associated with high‑grade CMTC. This tumor histologically displays a distinctive combination of growth patterns with morular structures. Strong diffuse nuclear and cytoplasmic immunostaining for β‑catenin is the hallmark of CMTC. Tumor cells are also positive for thyroid transcription factor‑1 and for estrogen and progesterone receptors, but negative for thyroglobulin and calcitonin. It is possible that the CMTC phenotype could result from blockage in the terminal/follicular differentiation of follicular cells (or their precursor cells) secondary to the permanent activation of the Wnt/β‑catenin pathway. In CMTC, the activation of the Wnt/β‑catenin pathway is the central pathogenetic event, which in FAP‑associated cases results from germline mutations of the APC regulator of WNT signaling pathway (APC) gene, and in sporadic cases from somatic inactivating mutations in the APC, AXIN1 and CTNNB1 genes. Estrogens appear to play a tumor‑promoting role by stimulating both the PI3K/AKT/mTOR and the RAS/RAF/MAPK signaling pathways. Additional somatic mutations (i.e. RET rearrangements, or KRAS, phosphatidylinositol‑4,5‑bisphosphate 3‑kinase catalytic subunit α, telomerase reverse transcriptase or tumor protein 53 mutations) may further potentiate the development and progression of CMTC. While hemithyroidectomy would be the treatment of choice for sporadic cases without high‑risk data, total thyroidectomy would be indicated in FAP‑associated cases. There is insufficient clinical data to propose therapies targeting the Wnt/β‑catenin pathway, but multikinase or selective inhibitors could be used in a manner analogous to that of conventional thyroid tumors. It is also unknown whether adjuvant antiestrogenic therapy could be useful in the subgroup of women undergoing surgery with high‑risk CMTC, as well as when there is tumor recurrence and/or metastasis.

Following the publication of this paper, it was drawn to the Editor\'s attention by a concerned reader that certain of the immunohistochemical data shown in Fig. 1A on p. 5, colony formation data shown in Figs. 2C, H and M and 6D on p. 6 and p. 10 respectively, the western blots in Fig. 2B, Transwell cell migration and invasion assay data in Fig. 3B, D and F, and immunofluorescence data in Fig. 4C had already appeared in previously published articles written by different authors at different research institutes (some of which have subsequently been retracted). Owing to the fact that the contentious data in the above article had already been published prior to its submission to Oncology Reports, the Editor has decided that this paper should be retracted from the Journal. After having been in contact with the authors, they accepted the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. [Oncology Reports 45: 72, 2021; DOI: 10.3892/or.2021.8023].

Placenta accreta spectrum (PAS) is one of the most dangerous complications in obstetrics, which can lead to severe postpartum bleeding and shock, and even necessitate uterine removal. The abnormal migration and invasion of extravillous trophoblast cells (EVTs) and enhanced neovascularization occurring in an uncontrolled manner in time and space are closely related to the abnormal expression of pro‑angiogenic and anti‑angiogenic factors. The pigment epithelium‑derived factor (PEDF) is a multifunctional regulatory factor that participates in several important biological processes and is recognized as the most efficient inhibitor of angiogenesis. The present study aimed to explore the effects of PEDF on EVT phenotypes and the underlying mechanisms in PAS. HTR‑8/SVneo cells were transfected to overexpress or knock down PEDF. Cell proliferation and invasion were assessed using Cell Counting Kit‑8, 5‑ethynyl‑2\'‑deoxyuridine and Transwell assays. In vitro angiogenesis was analyzed using tube formation assays. The degree of ferroptosis was assessed by evaluating the levels of lipid reactive oxygen species, total iron, Fe2+, malondialdehyde and reduced glutathione using commercial kits. The expression levels of biomarkers of ferroptosis, angiogenesis, cell proliferation and Wnt signaling were examined by western blotting. PEDF overexpression decreased the proliferation, invasion and angiogenesis, and induced ferroptosis of EVTs. Activation of Wnt signaling with BML‑284 and overexpression of vascular endothelial growth factor (VEGF) reversed the PEDF overexpression‑induced suppression of cell proliferation, invasion and tube formation. PEDF overexpression‑induced ferroptosis was also decreased by Wnt agonist treatment and VEGF overexpression. It was predicted that PEDF suppressed the proliferation, invasion and angiogenesis, and increased ferroptosis in EVTs by decreasing Wnt‑β‑catenin/VEGF signaling. The findings of the present study suggested a novel regulatory mechanism of the phenotypes of EVTs and PAS.

Oxaliplatin resistance usually leads to therapeutic failure and poor prognosis in colorectal cancer (CRC), while the underlying mechanisms are not yet fully understood. Metabolic reprogramming is strongly linked to drug resistance, however, the role and mechanism of metabolic reprogramming in oxaliplatin resistance remain unclear. Here, we aim to explore the functions and mechanisms of purine metabolism on the oxaliplatin-induced apoptosis of CRC.
An oxaliplatin-resistant CRC cell line was generated, and untargeted metabolomics analysis was conducted. The inosine 5\'-monophosphate dehydrogenase type II (IMPDH2) expression in CRC cell lines was determined by quantitative real-time polymerase chain reaction (qPCR) and western blotting analysis. The effects of IMPDH2 overexpression, knockdown and pharmacological inhibition on oxaliplatin resistance in CRC were assessed by flow cytometry analysis of cell apoptosis in vivo and in vitro.
Metabolic analysis revealed that the levels of purine metabolites, especially guanosine monophosphate (GMP), were markedly elevated in oxaliplatin-resistant CRC cells. The accumulation of purine metabolites mainly arose from the upregulation of IMPDH2 expression. Gene set enrichment analysis (GSEA) indicated high IMPDH2 expression in CRC correlates with PURINE_METABOLISM and MULTIPLE-DRUG-RESISTANCE pathways. CRC cells with higher IMPDH2 expression were more resistant to oxaliplatin-induced apoptosis. Overexpression of IMPDH2 in CRC cells resulted in reduced cell death upon treatment with oxaliplatin, whereas knockdown of IMPDH2 led to increased sensitivity to oxaliplatin through influencing the activation of the Caspase 7/8/9 and PARP1 proteins on cell apoptosis. Targeted inhibition of IMPDH2 by mycophenolic acid (MPA) or mycophenolate mofetil (MMF) enhanced cell apoptosis in vitro and decreased in vivo tumour burden when combined with oxaliplatin treatment. Mechanistically, the Wnt/β-catenin signalling was hyperactivated in oxaliplatin-resistant CRC cells, and a reciprocal positive regulatory mechanism existed between Wnt/β-catenin and IMPDH2. Blocking the Wnt/β-catenin pathway could resensitize resistant cells to oxaliplatin, which could be restored by the addition of GMP.
IMPDH2 is a predictive biomarker and therapeutic target for oxaliplatin resistance in CRC.

Imatinib resistance in chronic myelogenous leukemia (CML) is a clinical problem. The present study examined the role of N‑Myc downstream regulatory gene 3 (NDRG3) in imatinib resistance in CML. Quantitative PCR demonstrated that NDRG3 was highly expressed in patients with CML. Cell Counting Kit (CCK)‑8 experiments proved that NDRG3 promoted the proliferation of K562 CML cells and enhanced imatinib resistance. Dual‑luciferase assay showed that microRNA (miR)‑204‑5p inhibited expression of NDRG3 and immunofluorescence experiments showed that NDRG3 promoted accumulation of β‑catenin in the nucleus, thereby increasing the expression of downstream drug resistance‑ and cell cycle‑associated factors (c‑Myc and MDR1). At the same time, cell proliferation experiments showed that β‑catenin played a role in cell proliferation and drug resistance. Co‑transfection with small interfering (si)‑β‑catenin partially reversed the effect of NDRG3. This finding indicated that NDRG3 plays an important role in imatinib resistance and miR‑204‑5p and β‑catenin are involved in the biological behavior of NDRG3. The present results provide theoretical support for overcoming drug resistance in CML.

Oral cancer is one of the leading causes of death worldwide, with a reported 5‑year survival rate of ~50% after treatment. The treatment measures for oral cancer are very expensive and affordability is low. Thus, it is necessary to develop more effective therapies to treat oral cancer. A number of studies have found that miRNAs are invasive biomarkers and have therapeutic potential in a variety of cancers. The present study included 30 oral patients and 30 healthy controls. Clinicopathological characteristic and miR‑216a‑3p/β‑catenin expression level of 30 oral cancer patients were analyzed. In addition, two oral cancer cell lines (HSC‑6 and CAL‑27) were used for mechanism‑of‑action study. The expression level of miR‑216a‑3p was higher in oral cancer patients compared with healthy controls and positively associated with tumor stage. Inhibition of miR‑216a‑3p potently suppressed cell viability and induced apoptosis of oral cancer cells. It was found that effects of miR‑216a‑3p on oral cancer were through Wnt3a signaling. It was also found that the expression level of β‑catenin was higher in oral cancer patients compared with healthy controls and positively associated with tumor stage; the effects of miR‑216a‑3p on oral cancer were through β‑catenin. In conclusion, miR‑216a‑3p and the Wnt‑β‑catenin signaling pathway may be interesting candidates to develop effective therapies for oral cancers.

Forkhead box D1 (FOXD1) serves a critical role in colorectal cancer (CRC). FOXD1 expression is an independent prognostic factor in patients with CRC; however, the molecular mechanism and signaling pathway of FOXD1 that regulates cell stemness and chemoresistance has not been fully characterized. The aim of the present study was to further validate the effect of FOXD1 on the proliferation and migration of CRC cells, and to delve into the possible potential of FOXD1 in the clinical treatment of CRC. The effect of FOXD1 on cell proliferation was assessed using Cell Counting Kit 8 (CCK‑8) and colony formation assays. The effect of FOXD1 on cell migration was assessed by wound‑healing and Transwell assays. The effect of FOXD1 on cell stemness was assessed by spheroid formation in vitro and limiting dilution assays in vivo. The expression of stemness associated proteins, leucine rich repeat containing G protein‑coupled receptor 5 (LGR5), OCT4, Sox2 and Nanog, and epithelial‑mesenchymal transition associated proteins, E‑cadherin, N‑cadherin and vimentin, were detected by western blotting. Proteins interrelationships were assessed by a co‑immunoprecipitation assay. Oxaliplatin resistance was assessed using CCK‑8 and apoptosis assays in vitro, and using a tumor xenograft model in vivo. By constructing FOXD1 overexpression and knockdown stably transfected strains of colon cancer cells, it was revealed that the overexpression of FOXD1 increased CRC cell stemness and chemoresistance. By contrast, knockdown of FOXD1 produced the opposite effects. These phenomena were caused by the direct interaction between FOXD1 and β‑catenin, thus promoting its nuclear translocation and the activation of downstream target genes, such as LGR5 and Sox2. Notably, inhibition of this pathway with a specific β‑catenin inhibitor (XAV‑939) could impair the effects induced by the overexpression of FOXD1. In summary, these results indicated that FOXD1 may promote cell stemness and the chemoresistance of CRC by binding directly to β‑catenin and enhancing β‑catenin nuclear localization; therefore, it may be considered a potential clinical target.

Placental insufficiency is a common cause of intrauterine growth restriction (IUGR). It affects ~10% of pregnancies and increases fetal and neonatal morbidity and mortality. Although Wnt and Hh pathways are crucial for embryonic development and placentation, their role in the pathology of IUGR is still not sufficiently explored. The present study analyzed the expression of positive regulators of the Wnt pathway, WNT5A and β‑catenin, and the expression of the Hh pathway negative regulator suppressor of fused (SUFU). Immunohistochemical and reverse transcription‑quantitative PCR (RT‑qPCR) assays were performed on 34 IUGR and 18 placental tissue samples from physiologic singleton‑term pregnancies. Epigenetic mechanisms of SUFU gene regulation were also investigated by methylation‑specific PCR analysis of its promoter and RT‑qPCR analysis of miR‑214‑3p and miR‑378a‑5p expression. WNT5A protein expression was higher in endothelial cells of placental villi from IUGR compared with control tissues. That was also the case for β‑catenin protein expression in trophoblasts and endothelial cells and SUFU protein expression in trophoblasts from IUGR placentas. The SUFU gene promoter remained unmethylated in all tissue samples, while miR‑214‑3p and miR‑378a‑5p were downregulated in IUGR. The present results suggested altered Wnt and Hh signaling in IUGR. DNA methylation did not appear to be a mechanism of SUFU regulation in the pathogenesis of IUGR, but its expression could be regulated by miRNA targeting.

β‑catenin accumulates in hepatocellular carcinoma (HCC); therefore, understanding the mechanism of Wnt/β‑catenin pathway activation is important for HCC therapy. SAC3 domain containing 1 (SAC3D1) is involved in numerous types of cancer, such as gastric cancer. To the best of our knowledge, however, the role of SAC3D1 in HCC has not yet been elucidated. Here, the expression of SAC3D in HCC was examined by quantitative PCR, western blotting and immunohistochemistry. The function of SAC3D1 in HCC were examined using Cell Counting Kit‑8 and anchorage‑independent growth assay. It was found that the levels of SAC3D1 mRNA and protein were upregulated in HCC. When SAC3D1 was overexpressed, the proliferation of HCC cells was promoted; when the expression of SAC3D1 was disrupted, HCC cell growth was inhibited. When the molecular mechanism was investigated using immunoprecipitation, it was found that SAC3D1 interacted with axin, inhibiting ubiquitination of β‑catenin and elevating protein levels of β‑catenin. In summary, the present study revealed the promoting function of SAC3D1 in the progression of HCC. SAC3D1 may be a promising target for HCC therapy.

Rhabdomyosarcoma (RMS) is a highly aggressive soft tissue malignancy that predominantly affects children. The main subtypes are alveolar RMS (ARMS) and embryonal RMS (ERMS) and the two show an impaired muscle differentiation phenotype. One pathway involved in muscle differentiation is WNT signaling. However, the role of this pathway in RMS is far from clear. Our recent data showed that the canonical WNT/β‑Catenin pathway serves a subordinate role in RMS, whereas non‑canonical WNT signaling probably is more important for this tumor entity. The present study investigated the role of WNT5A, which is the major ligand of non‑canonical WNT signaling, in ERMS and ARMS. Gene expression analysis showed that WNT5A was expressed in human RMS samples and that its expression is more pronounced in ERMS. When stably overexpressed in RMS cell lines, WNT5A decreased proliferation and migration of the cells as demonstrated by BrdU incorporation and Transwell migration or scratch assay, respectively. WNT5A also decreased the self‑renewal capacity and the expression of stem cell markers and modulates the levels of muscle differentiation markers as shown by sphere assay and western blot analysis, respectively. Finally, overexpression of WNT5A can destabilize active β‑Catenin of RMS cells. A WNT5A knockdown has opposite effects. Together, the results suggest that WNT5A has tumor suppressive functions in RMS, which accompanies downregulation of β‑Catenin.