Correlation of thallium-201 uptake with proliferating cell nuclear antigen in brain tumours

The aim of this study was to assess the correlation between thallium-201 (201Tl) uptake and proliferative activity measured using the proliferating cell nuclear antigen labelling index (PCNA-LI) in brain tumours. Twenty-nine patients with brain tumours were included in this study. Of these, seven were diagnosed with meningioma, 13 had high grade glioma (HGG) and nine had low grade glioma (LGG). A 210Tl single photon emission computed tomography study was performed on all patients before operation, and 201Tl uptake index (UI) and retention index (RI) values were calculated. Cell proliferation was determined by PCNA. While all of the HGGs and meningiomas showed intense 201Tl accumulation on visual interpretation, eight of the nine LGGs did not show accumulation of 210Tl at the tumour site. 201Tl UI values were 3.23+/-0.89 and 2.67+/-0.66 in HGG, 1.27+/-0.18 and 1.23+/-0.09 in LGG, and 4.35+/-1.60 and 2.52+/-0.78 in meningioma on early and delay images, respectively. There was a statistical difference between the 201Tl UI in HGG and LGG. PCNA-LI values were 16.72+/-6.15%, 1.63+/-0.81% and 2.00+/-1.88% in HGG, LGG and meningioma, respectively. The PCNA-LI in HGG was significantly higher than in LGG and meningioma. While the correlation coefficient between the 201Tl UI and the PCNA-LI was 0.94 in gliomas (n=22), there was no correlation in meningiomas. No statistically significant correlation was found between the RI and the PCNA-LI in gliomas. The presence of a strong positive correlation between 201Tl uptake and PCNA-LI indicates that 201Tl uptake can predict the proliferative activity of the glioma.