Context Epigenetic alterations may play a role in the development and behaviour of Pituitary Neuroendocrine Tumours (PitNETs). Objective To evaluate the effect of methylation of Tumour Suppressor Genes (TSGs) in their gene expression and in the behaviour of PitNETs. Material and Methods We use MS-MLPA and q-RT-PCR techniques to analyse the DNA-promoter hypermethylation and the gene expression of 35 TSGs in 105 PitNETs. We define functionality, size and invasiveness of tumours according to their clinical manifestations, Hardy’s classification and MRI invasion of the cavernous sinus, respectively. Results We observed different methylation patterns among PitNET subtypes. CASP8 was the most hypermethylated gene in all PitNET subtypes. The methylation status of TP73 correlated negatively with their gene expression in the overall series (p=0.013) and in some subtypes. MSH6 and CADM1 showed higher methylation frequency in macro than in microadenomas in the overall series and in corticotroph PitNETs (all p≤0.053). ESR1 and RASSF1 were higher methylated in non-invasive than in invasive tumours in the overall series (p=0.054 and p=0.031, respectively) and in the gonadotroph subtype (sGT) (p=0.055 and p=0.050, respectively). ESR1 and CASP8 appeared more hypermethylated in functioning than in sCT (p=0.034 and p=0.034, respectively). Conclusions DNA-methylation of TSGs has a selective effect on their gene expression and on the growth and invasiveness of PitNETs. Its involvement in their functionality is biased because all silent operated tumours are macroadenomas while all operated microadenomas are functioning ones. Therefore, the subtypes of PitNETs should be considered as different entities.

High-risk features of colonic polyps are based on size, number, and pathologic characteristics. Surveillance colonoscopy is often recommended according to these findings. This study aimed to determine whether the molecular characteristics of polyps might provide information about the risk of metachronous advanced neoplasia. We retrospectively included 308 patients with colonic polyps. A total of 995 polyps were collected and tested for somatic BRAF and KRAS mutations. Patients were classified into 3 subgroups, based on the polyp mutational profile at baseline, as follows: non-mutated polyps (Wild-type), at least one BRAF-mutated polyp, or at least one KRAS-mutated polyp. At surveillance, advanced adenomas were defined as adenomas ≥ 10 mm and/or with high grade dysplasia or a villous component. In contrast, advanced serrated polyps were defined as serrated polyps ≥ 10 mm in any location, located proximal to the splenic flexure with any size or with dysplasia. At baseline, 289 patients could be classified as wild-type (62.3%), BRAF mutated (14.9%), or KRAS mutated (22.8%). In the univariate analysis, KRAS mutations were associated with the development of metachronous advanced polyps (OR: 2.36, 95% CI: 1.22–4.58; P = 0.011), and specifically, advanced adenomas (OR: 2.42, 95% CI: 1.13–5.21; P = 0.023). The multivariate analysis, adjusted for age and sex, also showed associations with the development of metachronous advanced polyps (OR: 2.27, 95% CI: 1.15–4.46) and advanced adenomas (OR: 2.23, 95% CI: 1.02–4.85). Our results suggested that somatic KRAS mutations in polyps represent a potential molecular marker for the risk of developing advanced neoplasia.

Gliomas are the most common brain tumors and include a variety of histologic types and grades of malignancy. They arise from glial cells and represent approximately 70% of the primary brain tumors. According to the criteria of the World Health Organization (WHO), the majority of gliomas can be classified into four grades of malignancy (I-IV). Virus infection, especially by DNA viruses and retroviruses, which may cause insertion of viral DNA sequences into the host genome, often triggers the host defense mechanisms. Particularly, the DNA methylation machinery can be activated to cause the methylation of foreign movable viral sequences and, therefore, silence viral gene expression. Several studies have shown the presence of Human Cytomegalovirus (HCMV) in glioblastoma, suggesting that the virus may participate in tumor pathogenesis. But this relationship is controversial because many other studies did not detect HCMV in these tumors. This study aims to detect the presence of HCMV in several samples of human glioma (94 formalin-fixed, paraffin-embedded samples and 28 snap-frozen samples) by different sensitive techniques. We have been unable to detect HCMV DNA and proteins in glioma samples. Therefore, arguments used so far to conclude that HCMV is an oncomodulator virus in gliomas must be, in our view, seriously reconsidered.

The aim of the present study is to check whether we can replicate, in an independent series, previous results showing that the molecular study of pituitary-specific gene expression complements the inmunohistochemical identification of pituitary neuroendocrine tumours. We selected 112 patients (51 (46.4%) women; mean age 51.4±16 years; 102 macroadenomas (91.9%), 9 microadenomas (8.1%)) with complete clinical, radiological, immunohistochemical and molecular data from our data set of pituitary neuroendocrine tumours. Patients were different from those previously studied. We measured the expression of the pituitary-specific hormone genes and type 1 corticotrophin-releasing hormone and arginine vasopressin 1b receptors, by quantitative real-time polymerase chain reaction using TaqMan probes. Afterwards, we identified the different pituitary neuroendocrine tumour subtypes following the 2017 World Health Organization classification of pituitary tumours, calculating the concordance between their molecular and immuhistochemical identification. The concordance between molecular and immunohistochemical identification of functioning pituitary neuroendocrine tumours with the clinical diagnosis was globally similar to the previous series, where the SYBR Green technique was used instead of TaqMan probes. Our results also corroborated the poor correlation between molecular and immunohistochemical detection of the silent pituitary neuroendocrine tumour variants. This discrepancy was more remarkable in lactotroph, null-cell and plurihormonal pituitary neuroendocrine tumours. In conclusion, this study validates the results previously published by our group, highlighting a complementary role for the molecular study of the pituitary-specific hormone genes in the typification of pituitary neuroendocrine tumours subtypes.