Interaction between Cigarette Smoke and Human Papillomavirus 16 E6/E7 Oncoproteins to Induce SOD2 Expression and DNA Damage in Head and Neck Cancer.

Even though epidemiological studies suggest that tobacco smoking and high-risk human papillomavirus (HR-HPV) infection are mutually exclusive risk factors for developing head and neck cancer (HNC), a portion of subjects who develop this heterogeneous group of cancers are both HPV-positive and smokers. Both carcinogenic factors are associated with increased oxidative stress (OS) and DNA damage. It has been suggested that superoxide dismutase 2 (SOD2) can be independently regulated by cigarette smoke and HPV, increasing adaptation to OS and tumor progression. In this study, we analyzed SOD2 levels and DNA damage in oral cells ectopically expressing HPV16 E6/E7 oncoproteins and exposed to cigarette smoke condensate (CSC). Additionally, we analyzed SOD2 transcripts in The Cancer Genome Atlas (TCGA) Head and Neck Cancer Database. We found that oral cells expressing HPV16 E6/E7 oncoproteins exposed to CSC synergistically increased SOD2 levels and DNA damage. Additionally, the SOD2 regulation by E6, occurs in an Akt1 and ATM-independent manner. This study suggests that HPV and cigarette smoke interaction in HNC promotes SOD2 alterations, leading to increased DNA damage and, in turn, contributing to development of a different clinical entity.

Epstein-Barr Virus Association with Breast Cancer: Evidence and Perspectives.

Epstein-Barr virus (EBV) is an enveloped DNA virus that belongs to the gamma Herpesviridae family. The virus establishes a latent/lytic persistent infection, though it can be involved in cancer development in some subjects. Indeed, evidence supports an etiological role of EBV in undifferentiated nasopharyngeal carcinoma (NPC), a subset of gastric carcinomas and lymphomas. Additionally, EBV has been detected in breast carcinomas (BCs) although its role has not been established. In this review, we summarize epidemiological information regarding the presence of EBV in BC and we propose mechanistic models. However, additional epidemiological and experimental evidence is warranted to confirm these models.

Characterization of High-Risk HPV/EBV Co-Presence in Pre-Malignant Cervical Lesions and Squamous Cell Carcinomas.

High-risk human papillomaviruses (HR-HPVs) are the etiological agents of cervical cancer. However, a low proportion of HR-HPV-infected women finally develop this cancer, which suggests the involvement of additional cofactors. Epstein−Barr virus (EBV) has been detected in cervical squamous cell carcinomas (SCCs) as well as in low- (LSIL) and high-grade (HSIL) squamous intraepithelial lesions, although its role is unknown. In this study, we characterized HR-HPV/EBV co-presence and viral gene expression in LSIL (n = 22), HSIL (n = 52), and SCC (n = 19) from Chilean women. Additionally, phenotypic changes were evaluated in cervical cancer cells ectopically expressing BamHI-A Rightward Frame 1 (BARF1). BARF1 is a lytic gene also expressed in EBV-positive epithelial tumors during the EBV latency program. HPV was detected in 6/22 (27.3%) LSIL, 38/52 (73.1%) HSIL, and 15/19 (78.9%) SCC cases (p < 0.001). On the other hand, EBV was detected in 16/22 (72.7%) LSIL, 27/52 (51.9%) HSIL, and 13/19 (68.4%) SCC cases (p = 0.177). HR-HPV/EBV co-presence was detected in 3/22 (13.6%) LSIL, 17/52 (32.7%) HSIL, and 11/19 (57.9%) SCC cases (p = 0.020). Additionally, BARF1 transcripts were detected in 37/55 (67.3%) of EBV positive cases and in 19/30 (63.3%) of HR-HPV/EBV positive cases. Increased proliferation, migration, and epithelial-mesenchymal transition (EMT) was observed in cervical cancer cells expressing BARF1. Thus, both EBV and BARF1 transcripts are detected in low- and high-grade cervical lesions as well as in cervical carcinomas. In addition, BARF1 can modulate the tumor behavior in cervical cancer cells, suggesting a role in increasing tumor aggressiveness.

Epstein-Barr Virus Infection in Lung Cancer: Insights and Perspectives.

Lung cancer (LC) is the leading cause of cancer death worldwide. Tobacco smoke is the most frequent risk factor etiologically associated with LC, although exposures to other environmental factors such as arsenic, radon or asbestos are also involved. Additionally, the involvement of some viral infections such as high-risk human papillomaviruses (HR-HPVs), Merkel cell polyomavirus (MCPyV), Jaagsiekte Sheep Retrovirus (JSRV), John Cunningham Virus (JCV), and Epstein-Barr virus (EBV) has been suggested in LC, though an etiological relationship has not yet been established. EBV is a ubiquitous gamma herpesvirus causing persistent infections and some lymphoid and epithelial tumors. Since EBV is heterogeneously detected in LCs from different parts of the world, in this review we address the epidemiological and experimental evidence of a potential role of EBV. Considering this evidence, we propose mechanisms potentially involved in EBV-associated lung carcinogenesis. Additional studies are warranted to dissect the role of EBV in this very frequent malignancy.

High-Risk Human Papillomavirus and Epstein-Barr Virus Coinfection: A Potential Role in Head and Neck Carcinogenesis.

High-risk human papillomaviruses (HR-HPVs) and Epstein-Barr virus (EBV) are recognized oncogenic viruses involved in the development of a subset of head and neck cancers (HNCs). HR-HPVs are etiologically associated with a subset of oropharyngeal carcinomas (OPCs), whereas EBV is a recognized etiological agent of undifferentiated nasopharyngeal carcinomas (NPCs). In this review, we address epidemiological and mechanistic evidence regarding a potential cooperation between HR-HPV and EBV for HNC development. Considering that: (1) both HR-HPV and EBV infections require cofactors for carcinogenesis; and (2) both oropharyngeal and oral epithelium can be directly exposed to carcinogens, such as alcohol or tobacco smoke, we hypothesize possible interaction mechanisms. The epidemiological and experimental evidence suggests that HR-HPV/EBV cooperation for developing a subset of HNCs is plausible and warrants further investigation.

Human Papillomavirus in Breast Carcinogenesis: A Passenger, a Cofactor, or a Causal Agent?

Breast cancer (BC) is the most commonly diagnosed malignancy in women worldwide as well as the leading cause of cancer-related death in this gender. Studies have identified that human papillomavirus (HPV) is a potential risk factor for BC development. While vaccines that protect against oncogenic HPVs infection have been commercially available, global disparities persist due to their high cost. Interestingly, numerous authors have detected an increased high risk (HR)-HPV infection in BC specimens when compared with non-tumor tissues. Therefore, it was suggested that HR-HPV infection could play a role in breast carcinogenesis in a subset of cases. Additional epidemiological and experimental evidence is still needed regarding the role of HR-HPV infection in the development and progression of BC.

Interplay between Epstein-Barr virus infection and environmental xenobiotic exposure in cancer.

Epstein-Barr virus (EBV) is a herpesvirus associated with lymphoid and epithelial malignancies. Both B cells and epithelial cells are susceptible and permissive to EBV infection. However, considering that 90% of the human population is persistently EBV-infected, with a minority of them developing cancer, additional factors are necessary for tumor development. Xenobiotics such as tobacco smoke (TS) components, pollutants, pesticides, and food chemicals have been suggested as cofactors involved in EBV-associated cancers. In this review, the suggested mechanisms by which xenobiotics cooperate with EBV for carcinogenesis are discussed. Additionally, a model is proposed in which xenobiotics, which promote oxidative stress (OS) and DNA damage, regulate EBV replication, promoting either the maintenance of viral genomes or lytic activation, ultimately leading to cancer. Interactions between EBV and xenobiotics represent an opportunity to identify mechanisms by which this virus is involved in carcinogenesis and may, in turn, suggest both prevention and control strategies for EBV-associated cancers.

Role of Pirin, an Oxidative Stress Sensor Protein, in Epithelial Carcinogenesis.

Pirin is an oxidative stress (OS) sensor belonging to the functionally diverse cupin superfamily of proteins. Pirin is a suggested quercetinase and transcriptional activator of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. Its biological role in cancer development remains a novel area of study. This review presents accumulating evidence on the contribution of Pirin in epithelial cancers, involved signaling pathways, and as a suggested therapeutic target. Finally, we propose a model in which Pirin is upregulated by physical, chemical or biological factors involved in OS and cancer development.

Role of BamHI-A Rightward Frame 1 in Epstein-Barr Virus-Associated Epithelial Malignancies.

Epstein-Barr virus (EBV) infection is associated with a subset of both lymphoid and epithelial malignancies. During the EBV latency program, some viral products involved in the malignant transformation of infected cells are expressed. Among them, the BamHI-A rightward frame 1 (BARF1) is consistently detected in nasopharyngeal carcinomas (NPC) and EBV-associated gastric carcinomas (EBVaGCs) but is practically undetectable in B-cells and lymphomas. Although BARF1 is an early lytic gene, it is expressed during epithelial EBV latency, mainly as a secreted protein (sBARF1). The capacity of sBARF1 to disrupt both innate and adaptive host antiviral immune responses contributes to the immune escape of infected cells. Additionally, BARF1 increases cell proliferation, shows anti-apoptotic effects, and promotes an increased hTERT activity and tumor formation in nude mice cooperating with other host proteins such as c-Myc and H-ras. These facts allow for the consideration of BARF1 as a key protein for promoting EBV-associated epithelial tumors. In this review, we focus on structural and functional aspects of BARF1, such as mechanisms involved in epithelial carcinogenesis and its capacity to modulate the host immune response.

Role of Epstein-Barr Virus and Human Papillomavirus Coinfection in Cervical Cancer: Epidemiology, Mechanisms and Perspectives.

High-risk human papillomavirus (HR-HPV) is etiologically associated with the development and progression of cervical cancer, although other factors are involved. Epstein-Barr virus (EBV) detection in premalignant and malignant tissues from uterine cervix has been widely reported; however, its contribution to cervical cancer development is still unclear. Here, a comprehensive analysis regarding EBV presence and its potential role in cervical cancer, the frequency of EBV/HR-HPV coinfection in uterine cervix and EBV infection in tissue-infiltrating lymphocytes were revised. Overall, reports suggest a potential link of EBV to the development of cervical carcinomas in two possible pathways: (1) Infecting epithelial cells, thus synergizing with HR-HPV (direct pathway), and/or (2) infecting tissue-infiltrating lymphocytes that could generate local immunosuppression (indirect pathway). In situ hybridization (ISH) and/or immunohistochemical methods are mandatory for discriminating the cell type infected by EBV. However, further studies are needed for a better understanding of the EBV/HR-HPV coinfection role in cervical carcinogenesis.

High-Risk Human Papillomavirus and Tobacco Smoke Interactions in Epithelial Carcinogenesis.

Cervical, anogenital, and some head and neck cancers (HNC) are etiologically associated with high-risk human papillomavirus (HR-HPV) infection, even though additional cofactors are necessary. Epidemiological studies have established that tobacco smoke (TS) is a cofactor for cervical carcinogenesis because women who smoke are more susceptible to cervical cancer when compared to non-smokers. Even though such a relationship has not been established in HPV-related HNC, a group of HPV positive patients with this malignancy are smokers. TS is a complex mixture of more than 4500 chemical compounds and approximately 60 of them show oncogenic properties such as benzo[α]pyrene (BaP) and nitrosamines, among others. Some of these compounds have been evaluated for carcinogenesis through experimental settings in collaboration with HR-HPV. Here, we conducted a comprehensive review of the suggested molecular mechanisms involved in cooperation with both HR-HPV and TS for epithelial carcinogenesis. Furthermore, we propose interaction models in which TS collaborates with HR-HPV to promote epithelial cancer initiation, promotion, and progression. More studies are warranted to clarify interactions between oncogenic viruses and chemical or physical environmental factors for epithelial carcinogenesis.

Human Papillomavirus 16 E7 Promotes EGFR/PI3K/AKT1/NRF2 Signaling Pathway Contributing to PIR/NF-κB Activation in Oral Cancer Cells.

A subset of oral carcinomas is etiologically related to high-risk human papillomavirus (HR-HPV) infection, with HPV16 being the most frequent HR-HPV type found in these carcinomas. The oncogenic role of HR-HPV is strongly dependent on the overexpression of E6 and E7 oncoproteins, which, in turn, induce p53 and pRb degradation, respectively. Additionally, it has been suggested that HR-HPV oncoproteins are involved in the regulation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), inducing cancer progression and metastasis. Previously, we reported that HPV16 E7 oncoprotein promotes Pirin upregulation resulting in increased epithelial-mesenchymal transition (EMT) and cell migration, with Pirin being an oxidative stress sensor and activator of NF-κB. In this study, we demonstrate the mechanism by which HPV16 E7-mediated Pirin overexpression occurs by promoting EGFR/PI3K/AKT1/NRF2 signaling, thus causing PIR/NF-κB activation in oral tumor cells. Our results demonstrate a new mechanism by which E7 contributes to oral cancer progression, proposing PIR as a potential new therapeutic target.

Merkel cell polyomavirus detected in head and neck carcinomas from Chile.

BACKGROUND: The role of human polyomaviruses (HPyVs) in epithelial tumors such as head and neck carcinomas (HNSCCs) including oral and oropharyngeal carcinomas has not been established. In this study, we evaluated for the first time the presence of Merkel cell polyomavirus (MCPyV), BK human polyomavirus (BKPyV), and JC human polyomavirus (JCPyV) in HNSCCs from Chilean subjects. METHODS: One hundred and twenty HNSCCs were analyzed for the presence of MCPyV, BKPyV and JCPyV using real-time polymerase chain reaction procedures. In addition, 54 oral brushes from age- and sex-paired subjects were analyzed. RESULTS: Of the total of 120 HNSCCs, 15 were positive for MCPyV (12.5%). Only one case was positive for BKPyV (0.8%) and none for JCPyV (0%). In subjects without cancer, only one case (1.8%) resulted positive for MCPyV and none for JCPyV and BKPyV. MCPyV was associated with HNSCCs (p = 0.0239; OR = 7.571; 95% CI: 1.192-81.46). No association was found between age (p = 0.1996), gender (p = 0.7111) or differentiation status (p > 0.9999) and MCPyV presence in HNSCCs. CONCLUSIONS: MCPyVs were detected in HNSCCs from Chilean patients and were not detected in oral brushes from patients without cancer. More studies are warranted for defining an etiological role and clinical/molecular consequences of these viruses in HNSCCs.

Aberrant expression of N-glycolyl GM3 ganglioside is associated with the aggressive biological behavior of human sarcomas.

BACKGROUND: The aberrant expression of N-glycolyl GM3 ganglioside (NeuGcGM3) in patients with sarcomas was reevaluated by assessing the relation of this molecule with some clinicopathological features and overall survival (OS) of patients. METHODS: Fifty formalin-fixed and paraffin-embedded specimens from patients diagnosed with sarcomas were included. For the evaluation of NeuGcGM3, the 14F7 monoclonal antibody followed by a peroxidase avidin-biotin system was used. Clinicopathological features were obtained from patient records. Survival rates were estimated by the Kaplan-Meier method and compared with the log-rank test. For multivariate analyses, the Cox regression model was used to identify independent prognostic factors for OS. RESULTS: The majority of samples had high levels of NeuGcGM3 expression (66.0%) that showed statistical correlation with age (p = 0.014), TNM stage (p = 0.022), histological grade (p = 0.013) and proliferation rates (p = 0.012). In addition, a tendency for association with tumor depth (p = 0.070) was evidenced. In univariate survival analysis, TNM stage (p = 0.000), occurrence of metastasis (p = 0.000) and expression of NeuGcGM3 (p = 0.034) were significant prognostic factors for OS, while a tendency for association was evidenced for histological grade (p = 0.091). Among these variables, only the presence of metastasis (p = 0.001) was an independent prognostic factor on multivariate analysis. CONCLUSIONS: The present research suggests the evaluation of NeuGcGM3 expression as a complementary prognostic factor in sarcoma, although our results need to be validated in a larger series and prospective studies. Moreover, our results could support the use of this molecule as a target for immunotherapy.

Synergistic potentiation of the anti-metastatic effect of anti EGFR mAb by its combination with immunotherapies targeting the ganglioside NGcGM3.

Several Anti-EGFR mAbs are register for the treatment of human cancer. However, their impact on patients overall survival has been limited by tumor resistance. N-Glycolyl variant of GM3 ganglioside (NGcGM3) is specifically expressed in some human tumors, and it has been associated with a poor prognosis. Several reports have documented that GM3 physically associates to EGFR inhibiting its ligand depend phosphorylation, but it also facilitates an alternative/compensatory signaling cascade mediated by Uroquinase Plasminogen Activator Receptor (uPAR) and integrin α5ß1 interaction. However, the difference between NGc and N-Acetylated (NAc) variants of GM3 regarding such interactions is unknown. We hypothesized that enrichment of NGcGM3 expression in tumors relates to advantages of this ganglioside, on ensuring both EGFR and uPAR pathways optimal function. We explored the impact of combining an anti-EGFR (7A7 mAb) with anti-NGcGM3 therapies: NGcGM3/VSSP vaccine or 14F7 mAb. Both combinations synergistically increase overall survival in two models of lung metastasis: 3LL-D122 and 4T1; but combination with NGcGM3/VSSP vaccine is significantly more effective. In 3LL-D122-metastasis, of mice treated with the best combination, both EGFR and uPAR/α5ß1 integrin pathways are turn off (I.e expression of uPAR/α5ß1; and phosphorylation of EGFR, Stat3, Src and FAK are reduced); and tumor angiogenesis is decreased. Interestingly, combination treatment increases tumor infiltrating CD4+T, CD8+T and NK+-cells. Furthermore, a positive clinical outcome is reported for a cancer patient treated with an anti-EGFR mAb and anti-NGcGM3 therapy. Overall, our results support the combination of anti EGFR antibodies with therapies targeting NGcGM3 to increase their efficacy in future clinical trials.

Sticholysin II-mediated cytotoxicity involves the activation of regulated intracellular responses that anticipates cell death.

Sticholysin II (StII) is a pore-forming toxin of biomedical interest that belongs to the actinoporin protein family. Sticholysins are currently under examination as an active immunomodulating component of a vaccinal platform against tumoral cells and as a key element of a nucleic acids delivery system to cell cytosol. These proteins form pores in the plasma membrane leading to ion imbalance and cell lysis. However, the intracellular mechanisms triggered by actinoporins upon binding to membranes and its consequences for cell death are barely understood. Here, we have examined the cytotoxicity and intracellular responses induced by StII upon binding to human B-cell lymphoma Raji in vitro. StII cytotoxicity involves a functional actin cytoskeleton, induces cellular swelling, lysis and the concomitant release of cytosol content. In addition, StII induces calcium release mainly from the Endoplasmic Reticulum, activates Mitogen-Activated Protein Kinase ERK and impairs mitochondrial membrane potential. Furthermore, StII stimulates the expression of receptor interacting protein kinase 1 (RIP1), normally related to different forms of regulated cell death such as apoptosis and necroptosis. In correspondence, necrostatin-1, an inhibitor of this kinase, reduces StII cytotoxicity. However, the mechanism of cell death activated by StII does not involve caspases activation, typical molecular features of apoptosis and pyroptosis. Our results suggest that, beyond pore-formation and cell lysis, StII-induced cytotoxicity could involve other regulated intracellular mechanisms connected to RIP1-MEK1/2 -ERK1/2- pathways. This opens new perspectives and challenges the general point of view that these toxins induce a completely unregulated mechanism of necrotic cell death. This study contributes to a better understanding of the molecular mechanisms involved in toxin-cell interaction and the implications for cell functioning, with connotation for the exploitations of these toxins in clinical settings.

Prognostic Significance of N-Glycolyl GM3 Ganglioside Expression in Non-Small Cell Lung Carcinoma Patients: New Evidences.

The prognostic role of N-glycolyl GM3 ganglioside (NeuGcGM3) expression in non-small cell lung carcinoma (NSCLC) still remains controversial. In this study, the NeuGcGM3 expression was reevaluated using an increased number of NSCLC cases and the 14F7 Mab (a highly specific IgG1 raised against NeuGcGM3). An immunohistochemical score integrating the percentage of 14F7-positive cells and the intensity of reaction was applied to reassess the relationship between NeuGcGM3 expression, some clinicopathological features, and the overall survival (OS) of NSCLC patients. The double and the triple expression of NeuGcGM3 with the epidermal growth factor receptor (EGFR) and/or its ligand, the epidermal growth factor (EGF), were also evaluated. NeuGcGM3 expression correlates with both S-Phase fraction (p = 0.006) and proliferation index (p = 0.000). Additionally, NeuGcGM3 expression was associated with a poor OS of patients in both univariate (p = 0.020) and multivariate (p = 0.010) analysis. Moreover, the double and/or the triple positivity of tumors to NeuGcGM3, EGFR, and/or EGF permitted us to identify phenotypes of NSCLC with a more aggressive biological behavior. Our results are in agreement with the negative prognostic significance of NeuGcGM3 expression in NSCLC patients. However, standardization of techniques to determine the expression of NeuGcGM3 in NSCLC as well as the implementation of a universal scoring system is recommended.

Human antibodies reactive to NeuGcGM3 ganglioside have cytotoxic antitumor properties.

N-glycolylated gangliosides are not naturally expressed in healthy human tissues but are overexpressed in several tumors. We demonstrate the existence of antibodies that bind (N-glycolylneuraminyl)-lactosylceramide (NeuGcGM3) and are detectable in the sera of 65 from the 100 donors (65%) tested by ELISA. From those 65 NeuGcGM3 antibody-positive donors, 35 had antibodies that were able to recognize and kill NeuGcGM3-expressing tumor cells by a complement-mediated mechanism. After complement inactivation, 11 of the 35 positive sera showed a direct cytotoxic effect on the tumor cells. This complement-independent cytotoxicity was dependent on the presence of antigen on the membrane and resembles an oncotic necrosis cell death. Both the levels of anti-NeuGcGM3 antibodies in the sera as well as the percentage of healthy donors with this immunity decreased with the age of the donor. In contrast to age and gender-matched healthy donors, we could only detect low reactivity against NeuGcGM3 in the sera of six out of 53 non-small cell lung cancer patients. These results suggest the existence of antibodies against NeuGcGM3 with antitumor immune surveillance functions, reinforcing the importance of N-glycolylated gangliosides as antitumor targets.

Tissue Reactivity of the 14F7 Mab Raised against N-Glycolyl GM3 Ganglioside in Tumors of Neuroectodermal, Mesodermal, and Epithelial Origin.

The expression of N-glycolylneuraminic acid forming the structure of gangliosides and/or other glycoconjugates (Hanganutziu-Deicher antigen) in human has been considered as a tumor-associated antigen. Specifically, some reports of 14F7 Mab (a highly specific Mab raised against N-glycolyl GM3 ganglioside) reactivity in human tumors have been recently published. Nevertheless, tumors of epithelial origin have been mostly evaluated. The goal of the present paper was to evaluate the immunohistochemical recognition of 14F7 Mab in different human tumors of neuroectodermal, mesodermal, and epithelial origins using an immunoperoxidase staining method. Samples of fetal, normal, and reactive astrocytosis of the brain were also included in the study. In general, nontumoral tissues, as well as, low-grade brain tumors showed no or a limited immunoreaction with 14F7 Mab. Nevertheless, high-grade astrocytomas (III-IV) and neuroblastomas, as well as, sarcomas and thyroid carcinomas were mostly reactive with 14F7. No reaction was evidenced in medulloblastomas and ependymoblastomas. Our data suggest that the expression of N-glycolyl GM3 ganglioside could be related to the aggressive behavior of malignant cells, without depending on the tumor origin. Our data could also support the possible use of N-glycolyl GM3 as a target for both active and passive immunotherapies of malignancies expressing this molecule.

Immunohistochemical Characterization of Three Monoclonal Antibodies Raised against the Epidermal Growth Factor and Its Receptor in Non-Small-Cell Lung Cancer: Their Potential Use in the Selection of Patients for Immunotherapy.

Adequate methods to identify which lung cancer patients are most likely to benefit from the targeted drugs against both epidermal growth factor receptor/epidermal growth factor (EGFR/EGF) are needed. For this reason, we evaluated both the tissue reactivity of ior egf/r3 monoclonal antibody (Mab) in human lung carcinomas and its biological activity in NCI-H125 cells. Additionally, we assessed the tissue expression of EGF using two Mabs, CB-EGF1 and CB-EGF2. The overexpression of EGFR was detected in 33.33% and 62.71% of small-cell lung carcinoma (SCLC) and non-small-cell lung carcinoma (NSCLC), respectively. The ability of ior egf/r3 Mab to bind the extracellular domain of EGFR inhibiting cell proliferation and inducing apoptosis in NCI-H125 cells was also demonstrated. The EGF expression was observed in about 17% and 70% of SCLC and NSCLC, respectively. However, differences in the reactivity of CB-EGF1 and CB-EGF2 were evidenced. A dual expression of EGFR and EGF was observed in 16.67% and 57.63% of SCLC and NSCLC patients, respectively. But, a correlation between them was only obtained in NSCLC. Our results permit to recommend the development of diagnostic kits using ior egf/r3 and/or CB-EGF1 Mabs in order to achieve a better selection of patients to EGFR/EGF-targeting treatment.