Fig. 5.

Keratin K77 in eccrine sweat glands and adnexal tumors. K77 mRNA and protein by in situ hybridization (ISH, a, a′) and indirect immunofluorescence (IIF, b-b′′) microscopy. This keratin is specifically expressed in the luminal cells (lc) of the intraglandular (igd), the intradermal (idd), the sweat duct ridge (sdr) and the intraepidermal/acrosyringial (ied/ac) duct of eccrine sweat glands of plantar skin. Peripheral duct cells are negative. The secretory portions (asterisks) are K77-negative. sb str. basale, ss str. spinosum, sg str. granulosum, sc str. corneum, gl glandular region with secretory and intraglandular duct portions. c Expression scheme of keratins of the eccrine sweat gland. d-d′′ Immunoperoxidase staining of K77 in the luminal cells of the eccrine sweat gland duct of the foot sole epidermis. K77 is also expressed in the tubular structures (arrows) of eccrine tumors such as syringoma (e) and cylindroma (f). Bars 100 μm