Are HDAC and Glutamine Synthetase Expression Levels Associated with Ga68-DOTATATE PET/CT Data and Prognosis in Gastroenteropancreatic Neuroendocrine Tumours?

Background and Objectives: Neuroendocrine neoplasms are heterogeneous tumours arising from endocrine gland cells and the neuroendocrine system. Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) constitute two-thirds of this tumour group. This study was aimed at investigating the relationship between histone deacetylase enzymes (HDAC) and glutamine synthetase (GS) positivity, and 68Ga-DOTATATE PET/CT data and their effect on prognosis in gastroenteropancreatic neuroendocrine tumours. Materials and Methods: Twenty-seven patients with Grade 1 and Grade 2 well-differentiated neuroendocrine tumours, diagnosed by biopsy and admitted to our nuclear medicine clinic for staging were included in the study. Results: There was no statistically significant correlation between HDAC and GS positivity in tumours and DOTATATE SUVmax value on PET/CT. There was no significant correlation between HDAC and GS positivity or negativity in the tumour and the presence or absence of metastasis on PET/CT. There was no statistically significant relationship between HDAC and GS positivity and survival. There was a statistically significant correlation between DOTATATE SUVmax value on PET/CT and survival (p = 0.039). Conclusions: According to the results of the present study, overall survival rates decreased in patients with high 68Ga-DOTATATE uptake on PET/CT and therefore, patients with high SUVmax on PET/CT should be followed closely and their prognosis may be poor. In addition, although not statistically significant, the mortality rate is higher in patients with HDAC-positive tumours compared to in patients with HDAC-negative tumours; thus, it should be kept in mind that the prognosis of such patients may also be poor. According to the results of the present study, GS levels were generally negative in NETs. In addition, there was no statistically significant relationship between GS levels and survival.