Background: LAT1/4F2hc heterodimeric complex is a major route for the transport of large neutral essential amino acids through the plasma membrane. Although it has been shown that LAT1/4F2hc is highly expressed in a variety of human tumors including gliomas, and LAT1 over-expression is associated with glioma grade and poor prognosis of glioma patients, the precise tissue location of LAT1/4F2hc in gliomas and the precise role of LAT1/4F2hc in glioma biological features remain unclear. Methods: In the current study, the expressions of LAT1, 4F2hc, CD34 and Ki-67 were investigated by immunohistochemistry in 62 cases of human brain glioma; LAT1/4F2hc expression level, Ki-67 labeling index (Ki-67 LI) and microvessel density (MVD) were measured semi-quantitatively; and the correlation of LAT1/4F2hc expression with histopathological features, Ki-67 LI and MVD in gliomas was further analyzed. Results: The results showed that both LAT1 and 4F2hc were expressed in all examined specimens. LAT1 but 4F2hc expression levels significantly correlated with the pathological grade and both expression levels significantly correlated with Ki-67 LI of gliomas. We also demonstrated that both LAT1 and 4F2hc immunoreactivity were observed in tumor cells as well as vascular endothelia; furthermore, the LAT1 expression level was markedly associated with glioma MVD as well. Conclusion: LAT1/4F2hc over-expression is closely correlates with the malignant phenotype and proliferation of gliomas, and LAT1 was associates with glioma angiogenesis. LAT1/4F2hc, especially LAT1, may become a novel potential molecular target for glioma biological therapy.

This paper summarizes the usefulness and limitation of positron emission tomography (PET) with¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) in the diagnosis and treatment of primary central nervous system lymphoma (PCNSL). The¹⁸F-FDG uptake in typical PCNSL is about 2.5 times higher than that in the normal gray matter, and the tumor can usually be identified visually. The¹⁸F-FDG uptake pattern and value provide useful information for differentiating PCNSL from other enhancing malignant brain tumors especially glioblastoma (GB). The¹⁸F-FDG uptake in typical PCNSL is usually homogenous, and the uptake value is significantly higher than that in GB. However,¹⁸F-FDG PET often fails to show the presence of tumor in the brain as¹⁸F-FDG uptake is faint in atypical PCNSL such as disseminated or nonenhancing lesions.¹⁸F-FDG PET is also useful for evaluating the treatment response at a very early stage after the initial treatment. Pretreatment and posttreatment¹⁸F-FDG uptake values may have a prognostic value in patients with PCNSL. In conclusion,¹⁸F-FDG PET is very useful in the diagnosis of typical PCNSL and can differentiate PCNSL from other malignant brain tumors. However, the usefulness of¹⁸F-FDG PET is limited in the diagnosis of atypical PCNSL.