Actively proliferating Lgr5+ skin stem cells are found deep in the hair follicle (HF). These cells renew the HF and drive its expansion in anagen phase. Their long residence and continuous mitotic activity make them prime candidates to transform into skin tumor-initiating cells. This was investigated by subjecting Lgr5-EGFP-Ires-CreERT2/R26R-LacZ mice (haired and hairless) to chemical and UV ca...

Mutations in the tumor suppressor p53 are detectable in over 50% of all human malignancies. Mutant p53 protein is incapable of transactivating its downstream target genes that are required for DNA repair and apoptosis. Chronic exposure to UVB induces p53 mutations and is carcinogenic in both murine and human skin. CP-31398, a styrylquinazoline compound, restores the tumor suppressor functions o...

inverted follicular keratosis (ifk) a benign tumor of skin appendages which is mostly presented as a solitary nodule with keratotic or scaling surface on the face of a middle aged or old patients but it can develop in other parts of the body. different studies have lead to development of different theories about the role of human papillomavirus (hpv) in this kind of skin tumor. the purpose of t...

We have investigated the effects of germ-line variants that influence skin tumor susceptibility loci on the patterns of somatic genetic alterations in mouse skin cancers. Using a two-stage skin carcinogenesis model, we previously identified at least 13 skin tumor susceptibility (Skts) loci in a large interspecific F1 backcross [(NIH/Ola x M. spretus) x NIH/Ola] study. In this report, we describ...

background : basal cell carcinoma is the most common form of skin cancer in men. increased marker expressions of apoptosis and cell proliferation have been found in the majority of basal cell carcinomas. our purpose was to determine whether any correlation between immunohistochemical expressions of p53 and ki-67 in different histopathological variants of basal cell carcinoma and patient’s age, ...

The clinical and morphological picture of Merkel cell carcinoma (MCC) may be rather challenging; therefore, the immunohistochemical profile plays a relevant role in confirming the microscopic diagnosis. A panel of antibodies including cytokeratins 20, 7 and epithelial membrane antigen, and neuron-specific enolase is used in confirming the morphological diagnosis of MCC. The majority of MCCs exp...

Tumor cells with donor genotype have been identified in human skin cancer after allogeneic transplantation; however, the donor contribution to the malignant epithelium has not been established. Kidney transplant recipients have an increased risk of invasive skin squamous cell carcinoma (SCC), which is associated with accumulation of the tumor suppressor p53 and TP53 mutations. In 21 skin SCCs f...

BACKGROUND The purpose of the study was to evaluate the effects of erlotinib on epidermal growth factor receptor (EGFR)-related signaling elements in tumor and skin from patients with advanced squamous cell carcinoma of the head and neck (HNSCC) and seek relationships between relevant clinical, biological, and pharmacokinetic parameters. PATIENTS AND METHODS Immunostaining for EGFR, p-EGFR, p...

The activity of dietary and topical administration of three retinoids, all-trans-retinoic acid, 13-cis-retinoic acid, and N-(4-hydroxyphenyl)retinamide (4-HPR), as promoters of skin tumor induction in SENCAR mice was studied. When administered as dietary supplements at their maximum tolerated dose levels, all three retinoids promoted tumorigenesis in mice initiated with a single topical dose of...