IMMUNOLOCALIZATION OF HCDC47 PROTEIN IN NORMAL AND NEOPLASTIC HUMAN TISSUES AND ITS RELATION TO GROWTH

hCDC47 is a human member of the MCM family, which has been implicated in the regulatory machinery causing DNA to replicate once per cell cyc le, We examined its protein expression and localization in normal huma n tissues, using immunostaining with polyclonal antibodies. Positive n uclei were found in the proliferative components of lymph nodes, bone marrow, epidermis and mucosa. Immunohistochemical analysis was also pe rformed for 3 types of cutaneous keratinocytic tumor originating from same cell type but showing different grades of malignancy. In seborrhe ic keratosis, a benign condition, cells with hCDC47-positive nuclei we re located in the outermost layers of the tumor lobules, while in Bowe n's disease, carcinomas in situ and squamous-cell carcinomas, they wer e present throughout the lesions. The percentages of hCDC47-positive c ells were 65.4% in squamous-cell carcinomas, 60.9% in Bowen's disease, 12.6% in seborrheic keratosis and 3.9% in normal epidermis (n = 5 in all cases). Further expansion of the analysis to include malignant tum ors from several other organs revealed that all malignant lesions test ed contained more nuclear hCDC47-positive cells than their normal coun terparts. Our findings indicate that hCDC47 plays a role in normal and neoplastic cell growth in vivo and that hCDC47 immunolocalization cou ld be used as an index of cell proliferation in tissue sections. (C) 1 997 Wiley-Liss, Inc.