Prognostic significance of transforming growth factor-α in human esophageal carcinoma implication for the autocrine proliferation

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Abstract
Background. The authors recently used immunostaining to demonstrate that patients with epidermal growth factor receptor (EGFR) overexpression have poor survival after surgery. However, the clinical significance of transforming growth factor (TGF)‐α, one of the ligands of EGFR, has not been demonstrated in esophageal carcinoma. Methods. Immunohistochemical study for TGF‐α and EGFR was performed on 57 esophageal squamous cell carcinomas using monoclonal antibodies. Results. TGF‐α expression was positive in 35% of the tumors, and EGFR overexpression, defined as stronger staining in cancer cells than in normal epithelium, was positive in 43% of the tumors, according to the authors' arbitrary criteria. The incidence of TGF‐α positivity was relatively higher in patients with the EGFR overexpression (EGFR+) than in the patients with nonoverexpression (EGFR‐). The survival rate was significantly lower in patients with TGF‐α(+) than in those with TGF‐α(‐) (P < 0.01) and in patients with EGFR(+) than in patients with EGFR(‐) (P < 0.01), respectively. Considering TGF‐α and EGFR expression simultaneously, the survival rate of the patients with TGF‐α(+)/EGFR(+) tumors was the lowest of the four subgroups, with statistically significant differences noted. These relationships between the immunoreactivities and survival curves were observed in the analysis within patients with node‐positive disease. In addition, a multivariate statistical analysis demonstrated that TGF‐α was the only significant variable, whereas EGFR and nodal status provided no additional information regarding postoperative survival. Conclusion. The results presented suggest that TGF‐α may act as an autocrine growth factor through hyperproducing EGFR and that its expression and EGFR overexpression may prove useful as a valuable prognostic indicator for patients with esophageal carcinoma.