WT1 IgG antibody for early detection of nonsmall cell lung cancer and as its prognostic factor

Abstract

There are urgent needs to develop methods for early detection of nonsmall cell lung cancer (NSCLC) because of its increasing incidence and poor prognosis. Here, we analyzed the production of IgG antibody (WT1 Ab) against WT1 (Wilms' tumor gene) protein that was overexpressed in the majority of NSCLC. Enzymelinked immuno-sorbent assay showed that WT1 Ab was produced in all of 91 NSCLC patients and 70 healthy individuals and that WT1 Ab titers were significantly higher in NSCLC patients compared with healthy individuals. When the cut-off level of WT1 Ab titers were fixed at mean 1 3SD of those in healthy individuals, 26.4% of NSCLC patients had WT1 Ab titers over the cut-off level, and positive rates of WT1 Ab at each clinical stage were 25.0, 30.8 and 38.4% in stage I, II and III NSCLC, respectively. When WT1 Ab was combined with CEA or CYFRA for detection of NSCLC, positive detection rates increased from 25.0 to 34.1 and 31.8%, respectively, in stage I and from 38.4 to 69.2 and 46.1%, respectively, in stage III, but not changed in stage II. Western blot analysis showed that dominant subclass of WT1 Ab was Th1-type IgG2. Interestingly, elevation of WT1 Ab titers was significantly associated with longer disease-free survival in patients with stages I-III NSCLC. These results showed that WT1 Ab could be a useful marker for early detection of NSCLC and its prognostic prediction. These results also suggested that WT1-specific immune responses played an important role in anti-cancer immunity in NSCLC. ' UICCKey words: lung cancer; WT1; humoral immune response; tumor marker; prognostic marker Lung cancer is the leading cause of cancer death in the world and nonsmall cell lung cancer (NSCLC) represents nearly 80% of the disease. 1 Because 75% of lung cancer patients are diagnosed at stages of metastatic spread when therapies are rarely curative, 2 early detection of localized lung cancer is the key to improve its clinical outcome.Although chest X-ray is routinely used as a screening tool, its limitation to detect localized lung cancer has been evident because of its insufficient sensitivity. 2 Recently, low-dose spiral computed tomography (CT) has been proposed as an early detection screening tool. However, despite its high sensitivity, specificity of CT in lung cancer detection is poor. 3 Therefore, serum biomarkers with high sensitivity and specificity for diagnosis of lung cancer are needed. However, current serum biomarkers for NSCLC such as carcino embryonic antigens (CEA) and squamous cell carcinoma antigen do not have sufficient sensitivity and specificity required for early detection of NSCLC. 4,5 It is now clear that malignant transformation occurs by changes in cellular gene expression with subsequent clonal proliferation. Altered gene expression in malignant cells may lead to the expression of aberrantly expressed proteins recognized by host immune system. If autoantibodies against these antigens are produced at early stage of NSCLC when quantity of the tumor antigens in the circulation is very small, these...

Enhancement of Efficacy of Wilms’ Tumor Gene WT1 Product-derived Peptide Cancer Vaccine by Co-administration with Immunopotentiating Agents: Lessons from Mouse Models

“…In addition, leukemia stem cells have been shown to express WT1, which supports the superiority of WT1 as a cancer antigen, because it indicates the possibility that WT1-directed immunotherapy can target cancer stem cells (Saito et al 2010 ). Furthermore, a series of investigations using clinical samples such as patients' peripheral blood demonstrated that WT1-directed cellular and humoral immune responses were generated in patients with malignancies (Sugiyama 2001(Sugiyama , 2002(Sugiyama , 2005(Sugiyama , 2010Oka et al 2006Oka et al , 2007Oka et al , 2008aOka et al , b , 2009Oka and Sugiyama 2010 ;Elisseeva et al 2002 ;Wu et al 2005 ;Oji et al 2009 ). These preclinical results urged us to perform a WT1-targeting cancer immunotherapy trial, and we started a WT1 peptide vaccine clinical trial in 2001 and demonstrated that WT1 peptide can induce WT1-specifi c immunologic responses and the associated clinical responses (Sugiyama 2001(Sugiyama , 2002(Sugiyama , 2005(Sugiyama , 2010Oka et al 2003Oka et al , 2004Oka et al , 2006Oka et al , 2007Oka et al , 2008aOka et al , b , 2009Oka and Sugiyama 2010 ;Tsuboi et al 2004Tsuboi et al , 2007Tsuboi et al , 2012Morita et al 2004 ;Iiyama et al 2007 ;Kawakami et al 2007 ;Izumoto et al 2008 ;Ohta et al 2009 ;Hashii et al 2010Hashii et al , 2012Chiba et al 2010 ).…”

Sensitive immunohistochemical detection of WT1 protein in tumors with anti‐WT1 antibody against WT1 235 peptide

“…GST-WT1 and GST-del-WT1 were produced according to the methods described previously. (20) Briefly, full-length WT1 and part of the WT1 gene corresponding to amino acids 180-324 were ligated into the pGEX-5X-3 vector (GE Healthcare, Buckinghamshire, UK) and transfected into E. coli. After collection of bacterial cells and extraction of the protein, GST-WT and GST-delWT1 protein were purified and used for western blotting analysis.…”

Cancer vaccine therapy based on peptides

“…WT1 is highly expressed in various malignancies and has been found to perform oncogenic function [15,16] . Both cellular and humoral immune responses against WT1 are naturally elicited in cancer patients, indicating strong immunogenicity of WT1 [17,18] . Several clinical studies using WT1 peptide-based immunotherapies have been performed with encouraging results for patients, including children, with various kinds of malignancies [19,20] .…”