Retrospective study on the correlation between 18-fluorodeoxyglucose uptake in positron emission tomography-computer tomography and tumour volume, cytological activity as assessed with Ki-67 and GLUT-1 staining in 10 cases of Merkel cell carcinoma

Role of Virus-Induced Host Cell Epigenetic Changes in Cancer

The tumor viruses human T-lymphotropic virus 1 (HTLV-1), hepatitis C virus (HCV), Merkel cell polyomavirus (MCPyV), high-risk human papillomaviruses (HR-HPVs), Epstein-Barr virus (EBV), Kaposi’s sarcoma-associated herpes virus (KSHV) and hepatitis B virus (HBV) account for approximately 15% of all human cancers. Although the oncoproteins of these tumor viruses display no sequence similarity to one another, they use the same mechanisms to convey cancer hallmarks on the infected cell. Perturbed gene expression is one of the underlying mechanisms to induce cancer hallmarks. Epigenetic processes, including DNA methylation, histone modification and chromatin remodeling, microRNA, long noncoding RNA, and circular RNA affect gene expression without introducing changes in the DNA sequence. Increasing evidence demonstrates that oncoviruses cause epigenetic modifications, which play a pivotal role in carcinogenesis. In this review, recent advances in the role of host cell epigenetic changes in virus-induced cancers are summarized.

Exploring the Prognostic Role of Ki67 Proliferative Index in Merkel Cell Carcinoma of the Skin: Clinico-Pathologic Analysis of 84 Cases and Review of the Literature

The exact prediction of outcome of patients with Merkel cell carcinoma (MCC) of the skin is difficult to determine, although several attempts have been made to identify clinico-pathologic prognostic factors. The Ki67 proliferative index is a well-known marker routinely used to define the prognosis of patients with neuroendocrine neoplasms. However, its prognostic value has been poorly investigated in MCC, and available published results are often contradictory mainly because restricted to small series in the absence of standardized methods for Ki67 evaluation. For this reason, we explored the potential prognostic role of Ki67 proliferative index in a large series of MCCs using the WHO standardized method of counting positive cells in at least 500 tumor cells in hot spot areas on camera-captured printed images. In addition, since MCC may be considered as the cutaneous counterpart of digestive neuroendocrine carcinomas (NECs), we decided to stratify MCCs using the available and efficient Ki67 threshold of 55%, which was found prognostic in digestive NECs. This choice was also supported by the Youden index analysis. In addition, we analyzed the prognostic value of other clinico-pathologic parameters using both univariate and multivariate analysis. Ki67 index appeared significantly associated with prognosis at univariate analysis together with stage IV, lack of MCPyV, and p63 expression, but not at the multivariate analysis, where survival resulted independently influenced by p63 expression and tumor stage, only.

The Link between Cytogenetics/Genomics and Imaging Patterns of Relapse and Progression in Patients with Relapsed/Refractory Multiple Myeloma: A Pilot Study Utilizing 18F-FDG PET/CT

Utilizing 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT), we performed this pilot study to evaluate the link between cytogenetic/genomic markers and imaging patterns in relapsed/refractory (RR) multiple myeloma (MM). We retrospectively analyzed data of 24 patients with RRMM who were treated at our institution between November 2018 and February 2020. At the last relapse/progression, patients had been treated with a median of three (range 1-10) lines of therapy. Six (25%) patients showed FDG avid extramedullary disease without adjacency to bone. We observed significantly higher maximum standardized uptake values (SUV_max) in patients harboring del(17p) compared with those without del(17p) (p = 0.025). Moreover, a high SUV_max of >15 indicated significantly shortened progression-free survival (PFS) (p = 0.01) and overall survival (OS) (p = 0.0002). One female patient exhibited biallelic TP53 alteration, i.e., deletion and mutation, in whom an extremely high SUV_max of 37.88 was observed. In summary, this pilot study suggested a link between del(17p)/TP53 alteration and high SUV_max on 18F-FDG PET/CT in RRMM patients. Further investigations are highly warranted at this point.

Metabolic reprogramming and angiogenesis in primary cutaneous Merkel cell carcinoma: expression of hypoxia-inducible factor-1α and its central downstream factors

BACKGROUND

Metabolic reprogramming and altered gene expression mediated by hypoxia-inducible factors play crucial roles during tumour growth and progression. Nevertheless, studies analysing the expression of hypoxia-inducible factor-1α and its downstream targets in Merkel cell carcinoma (MCC) are lacking but are warranted to shed more light on MCC pathogenesis and to potentially provide new therapeutic options.

OBJECTIVES

To analyse the immunohistochemical expression of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor-A (referred to as VEGF throughout the manuscript), VEGF receptor-2 (VEGFR-2), VEGF receptor-3 (VEGFR-3), glucose transporter-1 (Glut-1), monocarboxylate transporter 4 (MCT4) and carbonic anhydrase IX (CAIX) in primary cutaneous MCC.

METHODS

The 16 paraffin-embedded primary cutaneous MCCs (Merkel cell polyomavirus (McPyV) positive/negative: 11/5) were analysed by immunohistochemistry, namely HIF-1α, VEGF, VEGFR-2 (KDR), VEGFR-3 (FLT4), Glut-1, MCT4 and CAIX. An established quantification score (QS) was applied to quantitate the protein expression by considering the percentage of positive tumour cells (0: 0%; 1: up to 1%; 2: 2-10%; 3: 11-50%; 4: >50%) in relation to the staining intensity (0: negative; 1: low; 2: medium; 3: strong).

RESULTS

HIF-1α was expressed in all MCCs and predominantly found at the invading edges of tumour margins. The HIF-1α downstream factors Glut-1, MCT4 and CAIX were expressed in 13 of 16 MCC (81%), 14 of 16 MCC (88%) and 16 of 16 MCC (100%), respectively. Interestingly, VEGF and VEGFR-2 were not expressed in tumour cells, whereas VEGFR-3 was expressed in all MCCs. HIF-1α was expressed significantly stronger in McPyV⁺ tumours (QS: 10.36 ± 2.41) than in McPyV^- tumours (QS: 5.40 ± 1.34; P = 0.002). Similarly, VEGFR-3 was also expressed significantly stronger in McPyV⁺ tumours (QS: 10.00 ± 2.52) than in McPyV^- tumours (QS: 5.40 ± 3.43, P = 0.019).

CONCLUSIONS

Our data provide first evidence for a role of HIF-1α in induced metabolic reprogramming contributing to MCC pathogenesis. The metabolic signatures of McPyV⁺ and McPyV^- tumours seem to show relevant differences.

Associations between GLUT expression and SUV values derived from FDG-PET in different tumors-A systematic review and meta analysis

Purpose

Fluorodeoxyglucose-Positron-emission tomography (FDG-PET), quantified by standardized uptake values (SUV), is one of the most used functional imaging modality in clinical routine. It is widely acknowledged to be strongly associated with Glucose-transporter family (GLUT)-expression in tumors, which mediates the glucose uptake into cells. The present systematic review sought to elucidate the association between GLUT 1 and 3 expression with SUV values in various tumors.

Methods

MEDLINE library was screened for associations between FDG-PET parameters and GLUT correlation cancer up to October 2018.

Results

There were 53 studies comprising 2291 patients involving GLUT 1 expression and 11 studies comprising 405 patients of GLUT 3 expression. The pooled correlation coefficient for GLUT 1 was r = 0.46 (95% CI 0.40–0.52), for GLUT 3 was r = 0.35 (95%CI 0.24–0.46). Thereafter, subgroup analyses were performed. The highest correlation coefficient for GLUT 1 was found in pancreatic cancer r = 0.60 (95%CI 0.46–0.75), the lowest was identified in colorectal cancer with r = 0.21 (95% CI -0.57–0.09).

Conclusion

An overall only moderate association was found between GLUT 1 expression and SUV values derived from FDG-PET. The correlation coefficient with GLUT 3 was weaker. Presumably, the underlying mechanisms of glucose hypermetabolism in tumors are more complex and not solely depended on the GLUT expression.