Chiba M, Maley M A, Klein-Szanto A J
Cancer Res. 1986 Jan;46(1):259-63.
The histochemical pattern of gamma-glutamyltransferase (GGT) was studied in benign and malignant tumors produced by two different experimental protocols, two-stage carcinogenesis and complete carcinogenesis. Six percent of all papillomas produced by two-stage carcinogenesis were GGT positive, whereas 14% of benign tumors produced by complete carcinogenesis exhibited GGT-positive areas. The incidence of GGT-positive papillomas in the two-step carcinogenesis protocol increased up to wk 28 of treatment. After 32 wk, the incidence decreased abruptly, coinciding with an abrupt increase in the incidence of squamous cell carcinomas. On the other hand, the incidence of GGT-positive benign tumors produced during the course of complete carcinogenesis increased gradually up to wk 32 of treatment, coinciding with the increased incidence of squamous cell carcinomas. The incidence of GGT-positive keratoacanthomas and GGT-positive papillomas produced with the complete carcinogenesis protocol exhibited different patterns, suggesting different histogenesis and biological behavior of these two types of tumors. In addition, the labeling index of GGT-positive areas was lower (17 +/- 3%) than that of the GGT-negative areas (41 +/- 0.18%) of the same papillomas, indicating that the presence of GGT may be related to abnormal keratocyte differentiation rather than to proliferative changes.
采用两种不同的实验方案（两阶段致癌和完全致癌）诱导产生良性和恶性肿瘤，研究了γ-谷氨酰转移酶（GGT）的组织化学模式。两阶段致癌产生的所有乳头状瘤中，6%为GGT阳性，而完全致癌产生的良性肿瘤中，14%显示有GGT阳性区域。在两阶段致癌方案中，GGT阳性乳头状瘤的发生率在治疗第28周前上升。32周后，发生率突然下降，与此同时，鳞状细胞癌的发生率突然上升。另一方面，完全致癌过程中产生的GGT阳性良性肿瘤的发生率在治疗第32周前逐渐上升，与鳞状细胞癌发生率的上升一致。完全致癌方案产生的GGT阳性角化棘皮瘤和GGT阳性乳头状瘤的发生率呈现不同模式，提示这两种肿瘤的组织发生和生物学行为不同。此外，同一乳头状瘤中GGT阳性区域的标记指数低于GGT阴性区域（17±3%比41±0.18%），表明GGT的存在可能与角质形成细胞异常分化有关，而非与增殖变化有关。
