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Predominant formation of heavily pigmented dermal melanocytomas resembling ‘animal‐type’ melanomas in hepatocyte growth factor (C57BL/6 × C3H)F 1 mice following neonatal UV irradiation
Author(s) -
Florell Scott R.,
Thomas Joshua,
Grossman Douglas
Publication year - 2007
Publication title -
journal of cutaneous pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 75
eISSN - 1600-0560
pISSN - 0303-6987
DOI - 10.1111/j.1600-0560.2006.00679.x
Subject(s) - pathology , hepatocyte growth factor , melanoma , epidermis (zoology) , immunohistochemistry , biology , chemistry , medicine , anatomy , cancer research , receptor
Background: Transgenic mice expressing hepatocyte growth factor (HGF) develop cutaneous melanocytic tumors following neonatal UV exposure. Here, we examined the histologic spectrum of UV‐induced melanocytic tumors in HGF mice on a pigmented (C57BL/6 × C3H/HeN)F 1 background. Methods: Neonatally irradiated (4000 J/m 2 ) mice were monitored for 43 weeks, and 31/34 (91%) animals developed a total of 163 melanocytic tumors. Results: Of 54 primary tumors analyzed, most (49/54, 91%) demonstrated exclusively dermal collections of epithelioid cells with voluminous densely pigmented cytoplasm. Seven of these also demonstrated a population of spindled cells with mitoses. Several (3/54, 6%) tumors exhibited a junctional component with melanocytes present in the epidermis. Staining with PEP8 confirmed the presence of interfollicular melanocytes at the dermal‐epidermal junction in neonatal skin. Conclusions: In contrast to HGF animals on an albino (FVB) background, HGF animals on the pigmented (C57BL/6 × C3H/HeN)F 1 background do not develop classic radial growth phase melanoma but rather predominantly develop dermal melanocytomas resembling the ‘animal‐type’ melanoma occasionally seen in humans. These results demonstrate the influence of genetic background on histologic pattern of UV‐induced melanomas in mice.