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Background and Objectives Development of the system to express a suicide gene selectively in tumor cells is essential for gene therapy. We constructed a plasmid containing the diphtheria toxin A (DTA) fragment linked to human alpha-fetoprotein (AFP) promoter and enhancer, and tested whether it can exert its cytocidal effect selectively on AFP-producing cells. Methods The chloramphenical acetyltransferase (CAT) reporter gene or DTA gene was linked to the 5′ upstream region of the AFP gene. The plasmids were transfected into AFP-producing or non-producing cells by the lipopolyamine-coated DNA method. Expression of CAT activity and effects on cell growth of transfected cells were assessed. Results When the AFP-producing cells HuH-7 or HepG2 were cotransfected with CAT reporter plasmid and pAF5.1DTA plasmid, the CAT activity was greatly suppressed. In contrast, cotransfection with pAF5.1DTA-R, the inversely inserted DTA gene, did not inhibit CAT activity. Furthermore, cell growth of HuH-7 cells transfected with pAF5.1DTA plasmid was significantly inhibited compared with HuH-7 cells transfected with DTA-R plasmid. Conclusions Our results indicate that selective killing of AFP-producing cells will be attained by introducing the DTA gene linked to the promoter and enhancer region of AFP. J. Surg. Oncol. 1999;70:145–149. © 1999 Wiley-Liss, Inc.

A rare case of breast cancer associated with von Recklinghausen's neurofibromatosis is reported. This case and review of the literature illustrate the problems of clinical diagnosis.A 66-year-old woman who had undergone sigmoidectomy for sigmoid colon cancer two years previously, was admitted to the hospital because of a left breast skin retraction in October, 1998. The patient had von Recklinghausen's disease (neurofibromatosis type 1). The TNM clinical staging was TlcNOMO. Modified radical mastectomy was performed. The histopathological diagnosis of the breast tumor was invasive ductal carcinoma and the skin tumor was neurofibroma. The pTNM pathological staging was pTlcNlaMO.Among patients similar to our case, almost all were staged higher than T2. This may be because multiple neurofibromas obscure breast mass at palpation, leading to delayed detection of the cancer. Systemic and careful exploration is essential for patients with von Recklinghausen's neurofibromatosis to detect breast cancer at an early stage.

New highly sensitive phosphors of LiF-TLD were prepared for use in a low dose measurement. The phosphor was doped with three kinds of impurities which are Cu, Mg, and P, Si or B ion. Sensitivity of these phosphors doped with the third dopant was higher than that of TLD-600 LiF and, especially, the sensitivity of LiF(Mg, Cu, P) phosphor was about 23 times that of TLD-600 LiF, and nearly equal to Mg2SiO4(Tb) and CaSO4(Tm) phosphors. The thermoluminescence response to the dose increases sublinearly in the dose range of 1000 rad and more, but increases linearly in the dose range of 1000 rad and less. Tribothermoluminescence intensity increases with the vibrating period, and the maximum intensity is equivalent to about 300 mrad, but when the irradiated phosphor was heated up to about 270°C or less for evaluating the dose, the dose evaluation was scarcely affected. Application of this new phosphor to environmental radiation dosimeter and medical radiation dosimeter is discussed.