Temozolomide (TMZ) is an alkylating agent currently used as first-line therapy for gliomas treatment due to its DNA-damaging effect. However, drug resistance occurs, preventing multi-cycle use of this chemotherapeutic agent. One of the major mechanisms of cancer drug resistance is enhanced activity of a DNA repair enzyme, O6-methylguanine-DNA-methyltransferase (MGMT), which counteracts chemotherapy-induced DNA alkylation and is a key component of chemoresistance. MGMT repairs TMZ-induced DNA lesions, O6-meG, by transferring the alkyl group from guanine to a cysteine residue. This review provides an overview of recent advances in the field, with particular emphasis on the inhibitors of MGMT and underlying mechanisms. Literature search was performed through PubMed and all relevant articles were reviewed, with particular attention to MGMT, its role in TMZ-resistant gliomas, effects of MGMT inhibitors and the underlying mechanisms. Several strategies are currently being pursued to improve the therapeutic efficacy of TMZ via inhibition of MGMT to reduce chemoresistance and improve overall survival. MGMT may be a promising target for the treatment of TMZ-resistant gliomas.

Serum HE4 may be used as a potential marker to differentiate lung cancer from PTB and healthy controls. In addition, higher levels of HE4 predict poor prognosis in NSCLC patients.

ABSTRACT. The aim of this study was to characterize variations in Raf kinase inhibitor protein (RKIP) expression and related signaling molecules in gastric cardia adenocarcinoma. Cancerous and precancerous tissues were collected from patients with gastric cardia adenocarcinoma and normal tissue was collected from healthy controls. RKIP expression was detected in these tissues and the serum levels of NF-κB p65 and T-lymphocyte subsets were measured. Positive RKIP expression was higher in gastric cardia adenocarcinoma tissues than in precancerous tissues. The serum level of total NF-κB p65 was higher in patients with gastric cardia adenocarcinoma than in healthy controls. Levels of NF-κB p65 did not correlate with positive and negative expression of RKIP, but were higher in patients with lymph node metastasis than in those without it. The cellular immune function of the gastric cardia adenocarcinoma group was lower than in normal controls, particularly in cases with negative RKIP expression. RKIP is downregulated in gastric cardia adenocarcinoma tissues, which is related to the occurrence, progression, invasion, and metastasis of tumors. The possible mechanism for this may be the inhibition of NF-κB activity and cellular immune function, which allows for the escape of tumor cells from immune surveillance.

No abstract

ABSTRACT. Osteosarcoma is one of the most common bone malignancies in adolescents, and hereditary factors may influence its susceptibility. We assessed the association between XRCC3 Thr241Met polymorphism and susceptibility to osteosarcoma in a Chinese population. Between May 2012 and May 2014, a total of 136 osteosarcoma patients and 136 healthy control subjects were included in our study. The XRCC3 Thr241Met polymorphism was analyzed using a polymerase chain reaction restriction fragment length polymorphism assay. By multiple logistic regression analysis, individuals carrying the Met/Met genotype of XRCC3 Thr241Met were at significantly increased risk of osteosarcoma when compared with the Thr/Thr (OR = 2.50, 95%CI = 1.13-5.66). The Thr/Met+Met/Met genotype of XRCC3 Thr241Met was furthermore found to be correlated with an elevated increased risk of osteosarcoma when compared with the Thr/Thr genotype (OR = 1.71, 95%CI = 1.03-2.87), and Met/Met genotype of XRCC3 Thr241Met was associated with an increased risk of osteosarcoma compared to the Thr/ Thr (OR = 3.50, 95%CI = 1. 51-8.79). In conclusion, our study firstly reports 16485 XRCC3 Thr241Met polymorphism and osteosarcoma risk ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (4): 16484-16490 (2015) that XRCC3 Thr241Met gene polymorphism is associated with an elavated risk of osteosarcoma.