The enlargement of the hormone immune deprivation concept to the blocking of TGFalpha-autocrine loop: EGFR signaling inhibition

Effective inhibition of the epidermal growth factor/epidermal growth factor receptor binding by anti-epidermal growth factor antibodies is related to better survival in advanced non-small-cell lung cancer patients treated with the epidermal growth factor cancer vaccine

PURPOSE

Epidermal growth factor (EGF) might be a suitable immunotherapeutic target in non-small-cell lung cancer (NSCLC). Our approach consists of active immunotherapy with EGF. The aim of the study is to characterize the humoral response and its effects on signal transduction in relation with the clinical outcome.

EXPERIMENTAL DESIGN

Eighty NSCLC patients treated with first-line chemotherapy were randomized to receive the EGF vaccine or supportive care. EGF concentration in sera, anti-EGF antibodies and their capacity to inhibit the binding between EGF/EGF receptor (EGFR), and the EGFR phosphorylation were measured.

RESULTS

Seventy-three percent of vaccinated patients developed a good antibody response, whereas none of the controls did. In good antibody-responder patients, self EGF in sera was significantly reduced. In 58% of vaccinated patients, the post-immune sera inhibited EGF/EGFR binding; in the control group, no inhibition occurred. Post-immune sera inhibited the EGFR phosphorylation whereas sera from control patients did not have this capacity. Good antibody-responder patients younger than 60 years had a significantly better survival. A high correlation between anti-EGF antibody titers, EGFR phosphorylation inhibition, and EGF/EGFR binding inhibition was found. There was a significantly better survival for vaccinated patients that showed the higher capacity to inhibit EGF/EGFR binding and for those who showed an immunodominance by the central region of EGF molecule.

CONCLUSIONS

Immunization with the EGF vaccine induced neutralizing anti-EGF antibodies capable of inhibiting EGFR phosphorylation. There was a significant positive correlation between antibody titers, EGF/EGFR binding inhibition, immunodominance of anti-EGF antibodies, and survival in advanced NSCLC patients.

Expression of transforming growth factor alpha and epidermal growth factor receptor in Barrett's esophagus and esophageal adenocarcinoma

AIM: To investigate the expression of transform-ing growth factor alpha (TGF-α) and epidermal growth factor receptor (EGFR) in Barrett's esophagus and esophageal adenocarcinoma.

METHODS: Immunohistochemistry (SABC assay) was used to detect the expression of TGF-α and EGFR protein in patients with reflux esophagitis (n = 13), Barrett's esophagus (n = 17), esophageal adenocarcinoma (n = 11) and normal esophageal mucosa (n = 30).

RESULTS: In the development of reflux esophagitis, Barrett's esophagus and esophageal adenocarcinoma, the expression of TGF-α and EGFR protein increased gradually and closely correlated with each other (r = 0.951, P < 0.01). TGF-α protein was mainly expressed in the cytoplasm. EGFR was expressed in the cellular membrane in the normal esophageal mucosa and reflux esophagitis, but strongly positively expression was also observed in the cytoplasm and nucleus of cells in Barrett's esophagus with dysplasia and esophageal adenocarcinoma.

CONCLUSION: TGF-α and EGFR expression increase and may play synergic roles in the development of Barrett's esophagus and esophageal adenocarcinoma.