Epigenetic Deregulation of Protocadherin PCDHGC3 in Pheochromocytomas/Paragangliomas Associated With SDHB Mutations

CONTEXT

SDHB mutations are found in an increasing number of neoplasms, most notably in paragangliomas and pheochromocytomas (PPGLs). SDHB-PPGLs are slow-growing tumors, but ∼50% of them may develop metastasis. The molecular basis of metastasis in these tumors is a long-standing and unresolved problem. Thus, a better understanding of the biology of metastasis is needed.

OBJECTIVE

This study aimed to identify gene methylation changes relevant for metastatic SDHB-PPGLs.

DESIGN

We performed genome-wide profiling of DNA methylation in diverse clinical and genetic PPGL subtypes, and validated protocadherin γ-C3 (PCDHGC3) gene promoter methylation in metastatic SDHB-PPGLs.

RESULTS

We define an epigenetic landscape specific for metastatic SDHB-PPGLs. DNA methylation levels were found significantly higher in metastatic SDHB-PPGLs than in SDHB-PPGLs without metastases. One such change included long-range de novo methylation of the PCDHA, PCDHB, and PCDHG gene clusters. High levels of PCDHGC3 promoter methylation were validated in primary metastatic SDHB-PPGLs, it was found amplified in the corresponding metastases, and it was significantly correlated with PCDHGC3 reduced expression. Interestingly, this epigenetic alteration could be detected in primary tumors that developed metastasis several years later. We also show that PCDHGC3 down regulation engages metastasis-initiating capabilities by promoting cell proliferation, migration, and invasion.

CONCLUSIONS

Our data provide a map of the DNA methylome episignature specific to an SDHB-mutated cancer and establish PCDHGC3 as a putative suppressor gene and a potential biomarker to identify patients with SDHB-mutated cancer at high risk of metastasis who might benefit from future targeted therapies.

Experience after switching from insulin glargine U100 to glargine U300 in patients with type 1 diabetes mellitus. A study after one year of treatment in real life

INTRODUCTION

Current treatment of type 1 diabetes mellitus (T1DM) does not always achieve metabolic control because, among other things, the ocurrence of hypoglycemic events associated to insulin use.

MATERIAL AND METHODS

A descriptive real life study of 247 T1DM patients, 55.5% male, aged 46.53 ± 16.23 years, and with a mean diabetes duration of 21.89 ± 11.99 years, who were switched from basal insulin glargine U100 to glargine U300. The primary endpoints were changes in Hba1c and number of hypoglycemic events, while secondary endpoints included changes in weight and insulin dose after 6 and 12 months.

RESULTS

After one year, no changes were seen in HbA1c, but the proportion of patients with HbA1c values <7.5% increased at 6 months (33.5 vs. 40.5%; P<0.05) and remained stable during one year of follow-up. Hypoglycemic events significantly decreased after one year of treatment in patients with previous hypoglycemic events. No changes were seen in body weight. Total insulin dose (U/kg) increased 7.24% at 6 months of treatment and by 8.69% at one year, mainly due to basal insulin. No changes were seen between the doses given at 6 and 12 months. These changes were similar in the different metabolic control groups and in patients with or without hypoglycemia. This increase was not related with prior basal insulin dose, baseline HbA1c level, number of hypoglycemic events or baseline weight.

DISCUSSION

Glargine U300 is a good basal insulin alternative to treat T1DM, improving metabolic control in patients with HbA1c levels >7,5 and decreasing hypoglycemic events in patients with history of hypoglycemia without increasing body weight.

[Adrenocortical carcinoma. A retrospective analysis of five cases]

We present five cases of adrenal cortical carcinoma, diagnosed in our hospital and we describe the clinical presentation, diagnostic methods and treatment. It is a rare tumor, highly aggressive and prognosis is poor. The clinical presentation is characterized by a mass effect, symptoms caused by the invasion of the structures nearby or by a variety of hormonal changes, especially hypercortisolism and virilization. The diagnosis is based on the biochemical characterization of the hormonal profile and on imaging techniques, especially computed tomography and magnetic resonance. The treatment is generally surgical and the most effective chemotherapeutic agents are the adrenolytics (mitotane) alone or associated with doxorubicin, cisplatin and etoposide.