Published in Cancer Detection and Prevention 2000; 24(Supplement 1).

Bowen's disease showing spontaneous complete regression associated with apoptosis

A Kawada MD PhD 1, Y Aragane MD PhD 1, T Tezuka MD PhD 1, M Chisiki MD 2, A Ishibashi MD PhD 2

1 Kinki University School of Medicine, Osaka, Japan, 2 National Defense Medical College, Saitama, Japan,

AIM: To elucidate the involvement of apoptosis in spontaneous regression of malignant tumors, the expression of apoptosis-related proteins was investigated in the specimens from a patient showing spontaneous complete regression of Bowen's disease. METHODS: Formalin-fixed paraffin-embedded specimens of the primary and regressed lesions of Bowen's disease in a 68-year-old female patient were studied using Fas (APO- 1/CD95), Bcl-X and Mcl-1 antibodies. Additional four cases of Bowen's disease without regression were also investigated. RESULTS: Fas was strongly expressed in cell membranes of tumor cells in the epidermis of the diagnostic biopsy, whereas there was only faint expression in keratinocytes of the regressed lesion. Bcl-X and Mcl-1 were not strongly expressed in the primary or the regressed lesion. On the other hand, Fas was expressed faintly in the lesions of all the additional cases. The lesions in three cases expressed low to absent levels of Bcl X and Mcl-1, whereas one case showed localized higher expression of Bcl-X and Mcl-1 only in the upper epidermis. CONCLUSIONS: Strong expression of Fas antigen in the primary lesion and faint expression following regression suggest the involvement of Fas-mediated apoptosis in the spontaneous regression of our patient's Bowen's disease.

KEY WORDS: Bowen's disease, spontaneous regression, apoptosis, Fas.

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Paper presented at the International Symposium on Impact of Biotechnology on Cancer Diagnostic & Prognostic Indicators; Geneva, Switzerland; October 28 - 31, 2000; in the section on genetic instability.