Clinical implications of p53 autoantibodies in the sera of patients with non-small-cell lung cancer

Autoantibodies as diagnostic biomarkers for lung cancer: A systematic review

Lung cancer (LC) accounts for the largest number of tumor-related deaths worldwide. As the overall 5-year survival rate of LC is associated with its stages at detection, development of a cost-effective and noninvasive cancer screening method is necessary. We conducted a systematic review to evaluate the diagnostic values of single and panel tumor-associated autoantibodies (TAAbs) in patients with LC. This review included 52 articles with 64 single TAAbs and 19 with 20 panels of TAAbs. Enzyme-linked immunosorbent assays (ELISA) were the most common detection method. The sensitivities of single TAAbs for all stages of LC ranged from 3.1% to 92.9% (mean: 45.2%, median: 37.1%), specificities from 60.6% to 100% (mean: 88.1%, median: 94.9%), and AUCs from 0.416 to 0.990 (mean: 0.764, median: 0.785). The single TAAb with the most significant diagnostic value was the autoantibody against human epididymis secretory protein (HE4) with the maximum sensitivity 91% for NSCLC. The sensitivities of the panel of TAAbs ranged from 30% to 94.8% (mean: 76.7%, median: 82%), specificities from 73% to 100% (mean: 86.8%, median: 89.0%), and AUCs from 0.630 to 0.982 (mean: 0.821, median: 0.820), and the most significant AUC value in a panel (M13 Phage 908, 3148, 1011, 3052, 1000) was 0.982. The single TAAb with the most significant diagnostic calue for early stage LC, was the autoantibody against Wilms tumor protein 1 (WT1) with the maximum sensitivity of 90.3% for NSCLC and its sensitivity and specificity in a panel (T7 Phage 72, 91, 96, 252, 286, 290) were both above 90.0%. Single or TAAbs panels may be useful biomarkers for detecting LC patients at all stages or an early-stage in high-risk populations or health people, but the TAAbs panels showed higher detection performance than single TAAbs. The diagnostic value of the panel of six TAAbs, which is higher than the panel of seven TAAbs, may be used as potential biomarkers for the early detection of LC and can probably be used in combination with low-dose CT in the clinic.

Anti-vascular endothelial growth factor receptor (VEGFR) 2 autoantibody identification in glioblastoma patient using single B cell-based antibody gene cloning

Antibody direct cloning from single B cells is simple and efficient and has been successful in antibody identification of infectious diseases. However, although a recent whole-exome sequencing revealed abundant heterogeneic mutation accumulation in cancers, identification and synthesis of autoantibodies against specific cancer-associated antigens is still difficult in cancer patients owing to the very small number of B cells producing autoantibodies. In the present study, to identify autoantibodies targeting tumor antigens, we measured the titer of autoantibodies in high-grade glioma patients' plasma and identified two patients with elevated autoantibodies to a few transmembrane proteins. Specific B cells producing autoantibody against vascular endothelial growth factor receptor (VEGFR) 2 were immunostained with labeled protein and anti-human IgG antibody, and then collected by a single cell sorter. Finally, 22 antibody genes were successfully identified using direct IgG cloning from single B cell mRNA, and two antibody clones were found to have significant VEGFR2-specific binding affinity. The current direct human IgG gene cloning technique for identifying human antibodies derived from IgG-memory B cells avoids time-consuming procedures such as phage display-based antibody-library screening, and therefore may be applicable to identifying human autoantibodies in a variety of disorders including cancers even when antibody elevation is not detected because of a very small number of memory B cells.

Serum APE1 autoantibodies: a novel potential tumor marker and predictor of chemotherapeutic efficacy in non-small cell lung cancer

Apurinic/apyrimidinic endonuclease 1 (APE1), which has the dual functions of both DNA repair and redox activity, has been reported to be highly expressed in non-small cell lung cancer (NSCLC), and this appears to be a characteristic related to chemotherapy resistance. In this study, we identified serum APE1 autoantibodies (APE1-AAbs) in NSCLC patients and healthy controls by immunoblotting and investigated the expression of APE1-AAbs by indirect ELISA from the serum of 292 NSCLC patients and 300 healthy controls. In addition, serum APE1-AAbs level alterations of 91 patients were monitored before and after chemotherapy. Our results showed that serum APE1-AAbs can be detected in both NSCLC patients and healthy controls. Serum APE1-AAbs were significantly higher than those of healthy controls and closely related to APE1 antigen levels both in tumor tissues and the peripheral blood. Moreover, the change in levels of serum APE1-AAbs in NSCLC is closely associated with the response to chemotherapy. These results suggest that APE1-AAbs is a potential tumor marker and predictor of therapeutic efficacy in NSCLC.

Seromic profiling of ovarian and pancreatic cancer

Autoantibodies, a hallmark of both autoimmunity and cancer, represent an easily accessible surrogate for measuring adaptive immune responses to cancer. Sera can now be assayed for reactivity against thousands of proteins using microarrays, but there is no agreed-upon standard to analyze results. We developed a set of tailored quality control and normalization procedures based on ELISA validation to allow patient comparisons and determination of individual cutoffs for specificity and sensitivity. Sera from 60 patients with pancreatic cancer, 51 patients with ovarian cancer, and 53 age-matched healthy donors were used to assess the binding of IgG antibodies against a panel of >8000 human antigens using protein microarrays and fluorescence detection. The resulting data interpretation led to the definition and ranking of proteins with preferred recognition by the sera from cancer patients in comparison with healthy donors, both by frequency and strength of signal. We found that 202 proteins were preferentially immunogenic in ovarian cancer sera compared to 29 in pancreatic cancer, with few overlaps. Correlates of autoantibody signatures with known tumor expression of corresponding antigens, functional pathways, clinical stage, and outcome were examined. Serological analysis of arrays displaying the complete human proteome (seromics) represents a new era in cancer immunology, opening the way to defining the repertoire of the humoral immune response to cancer.

Prognostic implications of circulating anti-p53 antibodies in lung cancer--a review

Many independent prognostic markers have been identified for predicting survival and helping in the management of lung cancer cases. p53 protein overexpression and mutation have been the topic of numerous such publications. However, little is known about the role of anti-p53 antibodies as a prognostic marker in lung cancer. We searched the MEDLINE database and the bibliographies of the retrieved manuscripts and reviews. The retrieved studies are grouped according to the cohort studied. Out of 179 citations retrieved, 17 met our criteria. Seven studies used only non-small-cell lung cancer; four studies used only small-cell lung cancer; and six studies used the mixed cohort of both types of lung cancer. The studies varied in the concept design, cohort studied and the methodology. The prognostic role of anti-p53 antibodies in lung cancer remains contradictory and as some studies show an association with poor prognosis, others show a favourable association and still others showing no association what so ever. The frequency of detection of anti-p53 antibody is very low, highly specific with result being independent of the cohort studied. Adequate clinical trials, with optimized cohort, antigen and assay validation, are needed to address patients and physician's concerns regarding these associations.

A common repertoire of autoantibodies is shared by cancer and autoimmune disease patients: Inflammation in their induction and impact on tumor growth

The repertoire of autoantibodies found in cancer patients partly overlaps with that typical of patients with autoimmune diseases. Beside the biochemical and immunological properties of the target antigens and their altered expression in tumor tissues, the intratumoral inflammatory context can play a key role in the induction of autoimmune disease-associated autoantibodies in cancer patients. Furthermore, the impact of such antibodies on cancer growth and progression can be deeply influenced by the interplay with inflammation. The characterization of the spontaneous humoral responses occurring in cancer patients, of the mechanisms that trigger and sustain the autoantibody response and of the biological effects of such autoantibodies may help the rational design of anti-cancer immunotherapeutic protocols.

Application of protein microarrays for multiplexed detection of antibodies to tumor antigens in breast cancer

There is strong preclinical evidence that cancer, including breast cancer, undergoes immune surveillance. This continual monitoring, by both the innate and the adaptive immune systems, recognizes changes in protein expression, mutation, folding, glycosylation, and degradation. Local immune responses to tumor antigens are amplified in draining lymph nodes, and then enter the systemic circulation. The antibody response to tumor antigens, such as p53 protein, are robust, stable, and easily detected in serum; may exist in greater concentrations than their cognate antigens; and are potential highly specific biomarkers for cancer. However, antibodies have limited sensitivities as single analytes, and differences in protein purification and assay characteristics have limited their clinical application. For example, p53 autoantibodies in the sera are highly specific for cancer patients, but are only detected in the sera of 10-20% of patients with breast cancer. Detection of p53 autoantibodies is dependent on tumor burden, p53 mutation, rapidly decreases with effective therapy, but is relatively independent of breast cancer subtype. Although antibodies to hundreds of other tumor antigens have been identified in the sera of breast cancer patients, very little is known about the specificity and clinical impact of the antibody immune repertoire to breast cancer. Recent advances in proteomic technologies have the potential for rapid identification of immune response signatures for breast cancer diagnosis and monitoring. We have adapted programmable protein microarrays for the specific detection of autoantibodies in breast cancer. Here, we present the first demonstration of the application of programmable protein microarray ELISAs for the rapid identification of breast cancer autoantibodies.

Oncogene and tumor-suppressor gene products as serum biomarkers in occupational-derived lung cancer

Since lung cancer is the most frequent occupational cancer and one of the leading causes of cancer mortality in the world, it is one of the biggest challenges for research. In the literature, there are inconsistent results regarding the utility of the serum biomarkers p53, anti-p53 antibodies, EGF receptor or Ras. Based on the published results, routine use of these biomarkers for detection of occupationally derived lung carcinomas is not currently recommended. In this review, we summarize the literature and discuss the relevance of these oncogene and tumor-suppressor gene products as serum biomarkers in occupational-derived lung cancer.

Biomarkers in cancer screening, research and detection: present and future: a review

Biomarkers provide a powerful and dynamic approach to understanding the spectrum of malignancies with applications in observational and analytic epidemiology, randomized clinical trials, screening, diagnosis and prognosis. Defined as alterations in the constituents of tissues or body fluids, these markers offer a means for homogeneous classification of a disease and risk factor, and they can extend one's basic information about the underlying pathogenesis of disease. The goals in cancer research include finding biomarkers that can be used for the early detection of cancers, design individual therapies, and to identify underlying processes involved in the disease. Because so many myriad processes are involved in the diseased states, the goal is similar to 'finding a needle in a haystack'. However, the development of many -omic technologies, such as genomics and proteomics, has allowed us to monitor a large number of key cellular pathways simultaneously. This has enabled the identification of biomarkers and signalling molecules associated with cell growth, cell death and cellular metabolism. These are also facilitating in monitoring the functional disturbance, molecular and cellular damage, and damage response. This brief review describes the development of biomarkers in cancer research and detection with emphasis on different proteomic tools for the identification and discovery of new biomarkers, different clinical assays to detect various biomarkers in different specimens, role of biomarkers in cancer screening and last but not the least, the challenges in this direction of cancer research.

Multicenter Phase I Study of Repeated Intratumoral Delivery of Adenoviral p53 in Patients With Advanced Non–Small-Cell Lung Cancer

Purpose

To determine the feasibility, safety, humoral immune response, and biologic activity of multiple intratumoral injections of Ad5CMV-p53, and to characterize the pharmacokinetics of Ad5CMV-p53 in patients with advanced non–small-cell lung cancer (NSCLC).

Patients and Methods

Fifteen patients with histologically confirmed NSCLC and p53 mutations were enrolled onto this phase I trial. Nine patients received escalating dose levels of Ad5CMV-p53 (1 × 109 to 1 × 1011 plaque-forming units) as monotherapy once every 4 weeks. Six patients were treated on a 28-day schedule with Ad5CMV-p53 in combination with intravenous administration of cisplatin (80 mg/m2). Patients were monitored for toxicity, vector distribution, antibody formation, and tumor response.

Results

Fifteen patients received a total of 63 intratumoral injections of Ad5CMV-p53 without dose-limiting toxicity. The most common treatment-related toxicity was a transient fever. Specific p53 transgene expression was detected using reverse-transcriptase polymerase chain reaction in biopsied tumor tissues throughout the period of treatment despite of the presence of neutralizing antiadenovirus antibody. Distribution studies revealed that the vector was detected in the gargle and plasma, but rarely in the urine. Thirteen of 15 patients were assessable for efficacy; one patient had a partial response (squamous cell carcinoma at the carina), 10 patients had stable disease, with three lasting at least 9 months, and two patients had progressive disease.

Conclusion

Multiple courses of intratumoral Ad5CMV-p53 injection alone or in combination with intravenous administration of cisplatin were feasible and well tolerated in advanced NSCLC patients, and appeared to provide clinical benefit.

Prognostic value of immunohistochemical staining of p53, bcl-2, and Ki-67 in small cell lung cancer

Small cell lung cancer (SCLC) is one of the most fatal cancers in humans and many factors are known to be related to its poor prognosis. Immunohistochemical (IHC) stainings were done on SCLC specimens in order to investigate the prognostic value of the apoptosis-related gene expression and the tumor proliferative maker, and the relationships among these IHC results and patients clinical characteristics, chemoresponsiveness, and survival were analyzed. The medical records of 107 patients were reviewed retrospectively. IHC stainings for p53, bcl-2 and Ki-67 expressions were performed in the 66 paraffin-embedded biopsy samples. Sixty-six out of the 107 patients were evaluable for response rate and survival. The overall response rate was 75% (95% Confidence Interval=74-76%) and the median survival time was 14 months. The median survival time of limited stage was 16 months and that of extensive stage was 10 months. The prevalence of p53, bcl-2 and Ki-67 expression was 62%, 70%, and 49%, respectively. There were no correlations among the immunoreactivities of p53, bcl-2 and Ki-67 with clinical stage, chemoresponsiveness or overall survival. The clinical stage was the only prognostic factor influencing survival. The expression rates of p53, bcl-2, and Ki-67 were relatively high in SCLC without any prognostic significance. The exact clinical role of these markers should be defined through further investigations.

Identification of tumor associated antigens recognized by IgG from tumor-infiltrating B cells of lung cancer: correlation between Ab titer of the patient's sera and the clinical course

We previously demonstrated that TIB recognize tumor antigens and produce antibodies against them. In the present study, we identified three tumor antigens recognized by TIB in lung cancer and evaluated whether changes in the antibody titer against these antigens correlated with the patient's clinical course. A lung cancer cell line, G603L, was established from a primary lung tumor of a patient, G603. Seven months later, adrenal metastasis was detected and surgically resected. The latter tumor was mildly infiltrated with B cells and xenotransplanted into SCID mice to obtain human IgG. A cDNA library was constructed from G603L and SEREX was carried out using TIB-derived IgG. The sero-reactive clones were sequenced and one of these antigens was revealed to be MAGE-B2 whereas the others were novel antigens. In the immuno-monitoring of the patient's sera, high antibody titer against MAGE-B2 was observed before operation and the titer decreased after resection of the primary tumor. It was elevated again at the time of adrenal metastasis, but then decreased after resection. The change in antibody titer against the second antigen was similar to MAGE-B2, and the antibody titer against the third antigen was low before the primary operation but increased at the time of recurrence. Our results suggest that TIB recognized tumor antigens and the antibody titers against these antigens were changed along with the patient's clinical course. Therefore, these antibodies could be used as tumor markers for the patient.

The presence of anti-p53 antibodies in sera prior to thoracic surgery in non small cell lung cancer patients: its implications on tumor volume, nodal involvement, and survival

BACKGROUND

During recent years, a correlation between the presence of antibodies in sera against p53 and survival has been reported. The aim of the present study was to analyze anti-p53 antibodies in sera from patients with non small cell lung cancer (NSCLC) prior to thoracic surgery and their correlation to survival, nodal involvement, and tumor volume.

PATIENTS AND METHODS

Serum samples from 58 patients with NSCLC admitted to the Department of Pulmonary Medicine in Uppsala were collected between 1993 and 1995 and analyzed for the expression of anti-p53 antibodies.

RESULTS

Antibodies against p53 were detected in 12 patients (21%). No association was found between increased levels of anti-p53 antibodies and tumor volume (P =.84). There was a numerical trend towards higher levels of anti-p53 antibodies in patients without nodal disease, when compared with patients with nodal involvement, although not statistically significant (P =.136). However, when patients with metastatic disease were included, statistically significantly lower levels of anti-p53 antibodies were demonstrated, in comparison to patients without any sign of nodal engagement or metastatic disease (P =.038). Anti-p53 antibodies and survival showed no correlation between increasing index levels of anti-p53 antibodies and survival (P =.18). Neither was a correlation found between using the cutoff (>1.1) described by the manufacturer and survival.

CONCLUSION

The presence of anti-p53 antibodies was correlated neither to survival nor to tumor volume in the present study. However, patients with either nodal or metastatic disease had lower levels of anti-p53 antibodies in comparison to patients without signs of either nodal or metastatic disease. These issues are discussed.

Clinical implication of p53 mutation in lung cancer

Lung cancer development involves multiple genetic abnormalities leading to malignant transformation of the bronchial epithelial cells, followed by invasion and metastasis. One of the most common changes is mutation of the p53 tumor suppressor gene. The frequency of p53 alterations in lung cancer is highest in small cell and squamous cell carcinomas. A genetic "signature" of the type of p53 mutations has been associated with carcinogens in cigarette smoke. The majority of clinical studies suggest that lung cancers with p53 alterations carry a worse prognosis, and may be relatively more resistant to chemotherapy and radiation. An understanding of the role of p53 in human lung cancer may lead to more rational targeted approaches for treating this disease. P53 gene replacement is currently under clinical investigation but clearly more effective means of gene deliver to the tumor cells are required. Novel approaches to lung cancer therapy are needed to improve the observed poor patient survival despite current therapies.

Serum p53 antibodies in patients with lung cancer: correlation with clinicopathologic features and smoking

Abnormalities of p53 gene can lead to the production of p53 antibodies (p53-Abs) in the serum of cancer patients. This study was designed to investigate the prevalence of p53-Abs in 133 lung cancer patients and the distribution of these antibodies to clinicopathologic features and smoking status. Twenty five (18.8%) lung cancer patients were found to have p53-Abs. The presence of p53-Abs did not correlate with sex or age but showed frequent association with tumors of squamous cell carcinoma (31%) in comparison with adenocarcinoma (13.6%) (P=0.052). There was a statistically significant difference in the incidence of p53-Abs between early disease group (stage I-II) and the advanced group (stage III-IV) (P=0.036), however, there was no relationship between the presence of p53-Abs and overall survival. Interestingly, the frequent of p53-Abs was higher in smokers (27.1%) than in non-smokers (13.6%), though the difference was of borderline of statistical significance (P=0.061). These findings suggested that p53-Abs could be a potential biomarker for the study of individual with lung cancer.

Recent advances in the molecular diagnosis of lung cancer

Despite extensive effort in improvement of diagnosis and treatment of patients with lung cancer in past three decades, the overall survival of patients with the disease remains dismal. Because the development of lung cancer takes a few decades, early diagnosis of the disease or identification of truly high-risk populations may provide us opportunity to successfully cure or prevent the disease. Recent advances in understanding biological basis of lung tumorigenesis provide new tools for detecting malignant cells or the process of malignant transformation and progression. Along with identification of molecular abnormalities in the early lung tumorigenesis, advanced molecular analytic technologies have been emerged, which may facilitate development of rapid and effective methods for early diagnosis and risk assessment. Here, I discuss recent progresses in understanding of early molecular abnormalities in lung cancer, efforts of translating laboratory findings to clinical tests, and prospective of biomarkers in lung cancer diagnosis and risk assessment.

P53 autoantibodies in sera from Danish ovarian cancer patients and their correlation with clinical data and prognosis

The p53 gene, a tumour suppressor gene located on the short arm of chromosome 17 (17p13), is frequently mutated in various human tumours. Accumulation of p53 protein in neoplastic cells and its release following tumour necrosis can lead to development of circulating autoantibodies (AAb) against p53. Earlier studies of ovarian cancer (OC) patients reported different frequencies of p53 AAb and conclusions regarding the clinical and prognostic value of these AAb have not been in agreement. We therefore analysed for the presence of p53 AAb in a total of 227 preoperative serum samples from 193 OC patients and 34 patients with ovarian borderline tumours, and, in addition, serum samples from 86 healthy controls. An enzyme-linked immunosorbent assay (ELISA) was used to measure serum IgG antibodies against p53. The p53 protein used in the assay was produced as a hexahistidine-tagged fusion protein by baculovirus-infected Spodoptera frugiperda cells. Cut-off values for p53 AAb were evaluated, and correlations of p53 AAb with clinical-, biochemical data and survival were examined. We found a low sensitivity for p53 AAb alone, and no major additional effect of the detection rate of CA125 was found. No significant associations were found between p53 AAb and clinical stage, age, histological subtype and radicality after primary surgery. In contrast, we found significantly elevated CA125 levels in p53 AAb-positive patients compared to lower CA125 levels in p53 AAb-negative patients (p=0.003). No significant differences were found between p53 AAb-positive and p53 AAb-negative patients in the univariate and multivariate survival analyses. In conclusion, in a screening study for OC serum p53 AAb levels are of no diagnostic value, even if combined with the tumour marker CA125. The presence of increased serum p53 AAb in patients with diagnosed OC could not be correlated with any clinical data and preoperative serum p53 AAb status had no evident value.

Identification of breast cancer-restricted antigens by antibody screening of SKBR3 cDNA library using a preselected patient's serum

Screening of a breast cancer cDNA library from SKBR3 human breast cancer cells by SEREX (serological analysis of cDNA expression library) using a preselected serum from a breast cancer patient revealed 13 genes, two of which, INT-MI-1 and INT-MI-2, encode novel gene products, while the remaining 11 genes and their products are identical with or highly homologous to known GenBank entries. Immunoscreening of the 13 clones using 20 allogeneic sera from breast cancer patients and 20 samples from age- and gender-matched healthy donors showed that lactate dehydrogenase-A (LDH-A), lactate dehydrogenase-B (LDH-B), fibulin-1, and thyroid hormone-binding protein (THBP) were recognized principally by the breast cancer patient sera, indicating the immunogenicity of these molecules in vivo. The other antigens were similarly recognized by normal and patients sera, and thus not tumor-restricted immunologically. RT-PCR analysis revealed strong expression of fibulin-1 in tumor cell lines and surgical specimen whereas in the same experimental conditions, normal tissues scored negative. Also THBP expression was found in various tumors whereas in normal tissues, its expression is restricted to the testis and, at lower levels, in ovary, liver, and spleen. In contrast, LDH-A and LDH-B were ubiquitously expressed in normal and tumor tissues, with LDH-B levels considerably lower and heterogeneous in normal samples compared to those expressed in tumor cell lines. The differential expression of fibulin-1 between the normal tissues and breast carcinoma cell lines (5/6) and surgical specimens (5/6) suggests the possible involvement of the overexpression of this extracellular matrix-associated glycoprotein in the pathogenesis of this neoplasm.

Molecular biology of lung cancer: clinical implications

This review summarizes the rapidly expanding knowledge of the molecular pathogenesis of lung cancer. It is clear that respiratory epithelial cells require many genetic alterations to become invasive and metastatic cancer. Much more is to be learned, but with modern technology. Clinicians can detect "field cancerized" regions and preneoplastic and malignant cells, therefore offering the opportunity to intercede with biomarker-monitored prevention and early detection efforts. Such molecular screening and detection efforts will likely be coupled to advances in low-dose computed tomographic imaging, positron emission tomography scans, and other imaging modalities. Although this molecular marker approach has great potential, there is not yet a molecular marker validated in large prospective trials that has major independent predictive prognostic value. There is an urgent need for large, adequately powered, carefully designed prospective studies to identify clinically useful new biomarkers. Finally, new therapeutic strategies with genetic manipulation, small molecules, antibodies, vaccines, and, particularly, new drugs targeting specific biologic pathways found to be abnormal in lung provide for future optimism. Researchers need to define their individual value, especially when integrated with standard therapies.

Immunochemical studies of antigenic lymphoma-associated proteins

We have previously reported that plasma from patients with anaplastic lymphoma kinase (ALK)-positive lymphoma contains antibodies against the oncogenic kinase NPM-ALK protein characteristic of this disease. We investigated whether this reactivity represents a phenomenon unique to ALK-positive lymphoma by screening plasma from patients with follicular lymphoma for antibodies to BCL-2 protein. Eight out of 10 samples showed such reactivity (and in six cases gave specific staining of BCL-2-transfected cells). As these findings suggest a new biochemical approach to the identification of oncogenic proteins in lymphoma, we investigated whether antibodies present in patients with ALK-positive lymphoma can precipitate NPM-ALK in quantities which should be sufficient for further analysis. We found that plasma samples from all10 patients studied immunoprecipitated NPM-ALK asaprotein visible in silver-stained sodium dodecyl sulphatepolyacrylamide gels. Finally we demonstrated that NPM-ALK could be visualized more clearly if it were immunoprecipitated from extracts of cells in which newly synthesized proteins had been labelled with 35S and then identified by autoradiography. These results suggest a strategy for using patients' autoantibodies to screen for antibodies to other tumour-associated proteins.

Gene mutation as a target for early detection in cancer diagnosis

The increasing number of genetic aberrations implicated in the development of human cancer has prompted a search to detect them at the earliest possible stage of their formation. Of the many such genetic changes identified thus far, relatively few meet the standard for markers in early diagnosis and prognosis, namely that the genetic modifications occur during the early onset phase of cancer development. Parallel to the increasing number of such genes is the growing availability of technologies using more powerful and cost-efficient methods that enable mass screening for genetic alterations. The purpose of this review is to summarize the currently available genes that can serve as markers for early detection of cancers and methods that allow their detection.

Role of p53 as a prognostic factor for survival in lung cancer: a systematic review of the literature with a meta-analysis

The role of p53, as a prognostic factor for survival in lung cancer, is controversial and the purpose of the present systematic review of the literature is to determine this effect. Published studies were identified with the objective to aggregate the available survival results after a methodological assessment using a scale specifically designed by the European Lung Cancer Working Party (ELCWP). To be eligible, a study had to deal with p53 assessment in lung cancer (primary site) only, and to provide a survival comparison according to the p53 status. Among the 74 eligible papers, 30 identified p53 abnormalities as a univariate statistically significant poor prognostic factor and 56 provided sufficient data to allow survival results aggregation. There was no significant difference between the trials that either showed or did not show a prognostic effect of p53 according to the methodological score or to the laboratory technique used. The studies were categorized by histology, disease stage, treatment and laboratory technique. Combined hazard ratios suggested that an abnormal p53 status had an unfavourable impact on survival: in any stage nonsmall cell lung cancer (NSCLC) the mean (95% confidence interval) was 1.44 (1.20-1.72) (number of studies included in the subgroup was 11), 1.50 (1.32-1.70) in stages I-II NSCLC (n=19), 1.68 (1.23-2.29) in stages I-IIIB NSCLC (n=5), 1.68 (1.30-2.18) in stages III-IV NSCLC (n=9), 1.48 (1.29-1.70) in surgically resected NSCLC (n=20), 1.37 (1.02-1.85) in squamous cell carcinoma (n=9), 2.24 (1.70-2.95) in adenocarcinoma (n=9), 1.57 (1.28-1.91) for a positive immunohistochemistry with antibody 1801 (n=8), 1.25 (1.09-1.43) for a positive immunohistochemistry with antibody DO-7 (n=16), and 1.65 (1.35-2.00) for an abnormal molecular biology test (n=13). Data were insufficient to determine the prognostic value of p53 in small cell lung cancer. In each subgroup of nonsmall cell lung cancer, p53 abnormal status was shown to be associated with a poorer survival prognosis.

Low detection rate of p53 antibodies in sera of soft tissue sarcoma patients

Accumulation of the p53 gene product can lead to its immunogenic appearance and the generation of p53 serum antibodies (p53ab). In different cancer types the occurrence of detectable p53ab has an independent prognostic impact. In spite of the known p53 protein overexpression rate in soft tissue sarcomas (STS), up to 70%, there have been no investigations done on p53ab in serum in STS patients. In this prospective study of 50 STS patients, we investigated the presence of serum p53ab using an enzyme-linked immunosorbent assay system and the presence of p53 overexpression in the appropriate tissue specimen immunohistochemically. Using Kruskal-Wallis chi(2) and Kaplan-Meier tests the results were then correlated to histopathological and clinical data. Six of the 50 patients (12%) showed p53ab detectable in the serum, and 56% (28/50) of the tumors were p53 immunohistochemically positive. Four of the six p53ab positives (66%) had immunohistochemically p53 positive and two (33%) had negative tumors. Altogether four of the 50 patients (8%) were positive for p53ab in serum as well as for p53 immunohistochemistry in tumor tissue specimens. Twenty patients (40%) were negative for both. All of the p53ab positive patients had stage I or II tumors. Excluding tumor stage there was no p53ab correlation to histopathological, clinical or prognostic parameters. We conclude that in STS patients, p53ab also occurs but in contrast to other tumor types at a relatively low frequency. According to our results, the clinical value of p53ab seems to be limited in STS patients.

De-novo humoral immune responses to cancer-associated autoantigens during transition from chronic liver disease to hepatocellular carcinoma

A feature of hepatocellular carcinoma (HCC) is that antecedent liver cirrhosis and chronic hepatitis are common precursor conditions and during transition to malignancy some patients develop autoantibodies which were not present during the preceding chronic liver disease phase. Serum samples from such patients can be used to immunoscreen cDNA expression libraries to identify genes encoding the new autoantigens. We demonstrate here the de novo appearance of antibodies to p62, a cytoplasmic protein which has been shown to bind to a developmentally regulated fetal species of insulin-like growth factor II (IGF-II) mRNA. Another antibody appearing during the transition period was against CENP-F, a cell cycle-related nuclear protein with maximum expression in the G2 and M phases of the cell cycle and previously shown to have a high association with malignancy. In three additional patients in whom serial serum samples were examined, new appearance of anti-p62 was detected in two patients and anti-CENP-F in one patient. This study demonstrates that transition to malignancy can be associated with autoantibody responses to certain cellular proteins which might have some role in tumorigenesis.

p53 autoantibodies in patients with malignant mesothelioma: stability through disease progression

Malignant mesothelioma (MM) generally occurs as a pleural tumour, related to the inhalation of asbestos fibres. It is highly aggressive and largely unresponsive to treatment. The incidence of MM is particularly high in Western Australia because of the extensive blue asbestos mining operations that occurred in the north of the state until 1966. MM is unusual in that mutations in the tumour suppressor gene p53 are rarely observed, whilst over-expression of p53 protein is common. As the level of antibodies directed against p53 is thought to be of prognostic value in some cancers and as MM is known to be immunogenic, we studied a cohort of Western Australian patients to determine the prevalence of anti-p53 antibodies and their value as diagnostic markers or prognostic indicators. 6/88 (7%) of patients had high titres (>2 SD above the mean of controls) of anti-p53 antibodies. There was no correlation between antibody titre and survival. Although 3/38 (8%) of sera obtained from patients exposed to asbestos but prior to a diagnosis of MM contained antibodies, the same proportion of sera obtained from patients exposed to asbestos but who remained disease free also contained antibodies (2/40; 8%). Sera collected sequentially demonstrated a profound temporal stability in the titre of anti-p53 antibodies in patients with MM throughout the course of their illness. These results show that anti-p53 antibodies are observed only at a low frequency in the sera of MM patients and where they do occur, their elicitation is an early event that may be unrelated to antigen load. The occurrence of anti-p53 antibodies does not serve as either a useful prognostic or diagnostic indicator in MM.

Serum p53 antibodies in small cell lung cancer: the lack of prognostic relevance

Prognostic relevance of serum p53 antibodies was assessed in 96 patients with microscopically proven small cell lung cancer (SCLC). The study group included 67 males and 29 females; mean age 58 years; range 35--86 years; 60 with limited disease (LD), and 36 with extensive disease (ED). The control group consisted of 41 patients with non-malignant diseases. The presence of p53 antibodies was assayed by the immunoenzymatic method (P53 ELISA kit, PharmaCell, France). Antibodies were present in 26 SCLC cases (27%); 15 (25%) in LD and 11 (31%) in ED. Antibodies were also found in one out of 41 control subjects (2%). There was no correlation between the level of antibodies and clinical characteristics of SCLC patients including age, gender and extent of disease. The median follow-up for the entire group was 30 months (range: 11--39 months). By the time of analysis, 78 patients (82%) had deceased. Median survival in SCLC patients with and without antibodies was 42 and 39 weeks, respectively (log rank, P=0.81). These results indicate the lack of clinical relevance of serum p53 antibodies in SCLC.

Serum p53 antibodies: predictors of survival in small-cell lung cancer?

Serum p53 antibodies have been shown to be a poor prognostic marker in resected non-small-cell lung cancer (NSCLC), but studies in small-cell lung cancer (SCLC) have been contradictory. We have studied the incidence of p53 antibodies in a large SCLC cohort treated at one oncology centre and correlated the results with survival. 231 patients (63% male, median age 65), diagnosed and treated for SCLC between 1987 and 1994 at The Royal Marsden Hospital NHS Trust, had sera stored pretreatment. All samples were tested for p53 antibodies (p53-Ab) using a standardized ELISA technique with a selection of strongly ELISA positive, weakly ELISA positive and negative samples being confirmed with immunoprecipitation. 54 patients were positive for p53-Ab (23%). The presence of a high titre of p53-Ab (titre ratio >5) appears to be associated with a survival advantage with a relative risk of death of 1.71 (95% CI: 1.14-2.58) in those without the antibody (P = 0.02). This study, the largest homogeneous group so far looking at p53-Ab in SCLC, suggests that p53 antibody detection may have a role in predicting outcome in this type of cancer.

Molecular pathogenesis of lung cancer

Lung cancer is the largest cancer killer of men and women in the united states. In addition to the progress made from antismoking primary prevention measures, new tools to help treat patients with lung cancer are emerging from the rapid advances in knowledge of the molecular pathogenesis of lung cancer. These tools include molecular and cellular biology and are starting to provide an insight into how the tumor cell, by altering oncogenes and tumor suppressor genes, achieves growth advantage, uncontrolled proliferation and metastatic behavior via disruption of key cell-cycle regulators and signal transduction cascades. Moreover, new knowledge is being developed in terms of the molecular definition of individual susceptibility to tobacco smoke carcinogens. These tools are being translated into clinical strategies to complement surgery, radiotherapy, and chemotherapy and also to assist in primary and secondary prevention efforts. This review summarizes current knowledge of the molecular pathogenesis of lung cancer. From this we know that respiratory epithelial cells require many genetic alterations to become invasive and metastatic cancer. We can detect cells with a few such changes in current and former smokers, offering the opportunity to intercede with a biomarker-monitored prevention and early detection effort. This will be coupled with new advances in computed tomography-based screening. Finally, because the molecular alterations are known, new mechanism-based therapies are being developed and brought to the clinic, including new drugs, vaccines, and gene therapy, which also must be integrated with standard therapies.