The role of TP53 and MDM2 polymorphisms in TP53 mutagenesis and risk of non-melanoma skin cancer.

P53 is a key regulatory molecule in the cellular response to ultraviolet radiation, and TP53 mutation is the most common alteration in non-melanoma skin cancer. The MDM2 oncogene negatively regulates p53 protein levels, and both genes have functional polymorphisms that may modify skin cancer risk. Furthermore, prior research suggests that TP53 mutations preferentially occur on the arginine allele to selectively inactivate the p63 pathway. We tested these hypotheses of susceptibility and preferential mutation in non-melanoma skin cancer. The TP53 Arg72Pro and MDM2 309 polymorphisms were genotyped in a population-based case-control study of non-melanoma skin cancer, and TP53 alteration (mutation and immunohistochemistry staining) was evaluated in case tumors. In 902 cases of basal cell carcinoma (BCC), 676 cases of squamous cell carcinoma (SCC) and 812 controls, no association was found between the TP53 polymorphism and risk of non-melanoma skin cancer [odds ratio (OR)(BCC) 0.98, 95% confidence interval (CI) 0.80-1.20; OR(SCC) 0.93, 95% CI 0.75-1.16]. However, carriers of the MDM2 SNP309 G allele did have an elevated risk of non-melanoma skin cancer (OR(BCC) 1.15, 95% CI 0.93-1.42; OR(SCC) 1.29, 95% CI 1.02-1.63). We observed an association between TP53 alterations in the tumors and constitutive TP53 genotype (P < 0.01), with alterations preferentially occurring on the proline allele. Collectively, these data highlight the significant effects of genotype on gene-specific mutation events in carcinogenesis.

Analgesic and nonsteroidal anti-inflammatory use in relation to nonmelanoma skin cancer: a population-based case-control study.

BACKGROUND: Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) are potentially chemopreventive. OBJECTIVE: We examined the relation between NSAID use and nonmelanoma skin cancer in a population-based case-control study. METHODS: NSAID and analgesic use was analyzed in 1484 participants: 535 with squamous cell carcinoma (SCC), 487 with basal cell carcinoma (BCC), and 462 control subjects. RESULTS: Use of NSAIDs, particularly aspirin, was associated with a reduced odds ratio (OR) of SCC, especially tumors positive for p53 (OR 0.29; 95% confidence interval 0.11-0.79) or with PTCH loss of heterozygosity (OR 0.35; 95% confidence interval 0.13-0.96). Although not considered a NSAID, decreased ORs of both basal cell carcinoma and SCC were observed in relation to use of paracetamol (acetaminophen). Risk of BCC was unrelated to NSAID use. LIMITATIONS: Self-reported drug use was a limitation. CONCLUSIONS: This study supports the hypothesis that NSAIDs, aspirin in particular, may reduce risk of SCC and may affect specific molecular subtypes of SCC.

Spitz nevi arising in speckled lentiginous nevus: clinical, histologic, and molecular evaluation of two cases.

Spitz nevi are small dome-shaped nodules that sometimes arise in areas of preexisting hyperpigmentation, such as a speckled lentiginous nevus (nevus spilus), where they present a diagnostic dilemma. We report clinical, histopathological, and molecular findings of two cases of multiple Spitz nevi arising in a speckled lentiginous nevus. We used immunohistochemistry to assess expression of Ki-67, epidermal growth factor receptor, vascular endothelial growth factor, and RelA in two cases of Spitz nevi arising in a speckled lentiginous nevus. We observed rare staining for the proliferative marker Ki-67, but positive staining for the growth and antiapoptotic factors epidermal growth factor receptor, vascular endothelial growth factor, and RelA. Characterization of the molecular phenotype of Spitz nevi arising in speckled lentiginous nevi may provide a useful adjunct to long-term monitoring in this rare but difficult clinical presentation.

Ichthyotic-appearing skin changes associated with childhood morphea, systemic sclerosis, and systemic lupus erythematosus/scleroderma overlap.

Ichthyotic-appearing skin changes have been associated with autoimmune disorders, including systemic lupus erythematosus and systemic sclerosis in adults. We report three children with ichthyotic-appearing skin changes that may be an early feature reflecting underlying dermal sclerosis. Detection of these subtle skin changes may be predictive of more widespread cutaneous involvement, ultimately prompting earlier treatment.

Multiple granular cell tumors in a child with Noonan syndrome.

Granular cell tumors are benign neurally derived neoplasms, involving cutaneous and subcutaneous tissues; and typically occur as solitary lesions. Multiple granular cell tumors occur in 10% of affected individuals, but are in children. Children with underlying somatic and genetic syndromes, including neurofibromatosis and Noonan syndrome, appear to be at higher risk of developing multiple granular cell tumors. Skin biopsy assists in diagnosis, since granular cell tumors have a similar appearance to other cutaneous nodules. Painful or rapidly growing granular cell tumors should be excised and asymptomatic non-growing granular cell tumors may be observed. Children with multiple granular cell tumors should have a complete physical examination to rule out an underlying genetic syndrome.

Lentigo maligna (melanoma in situ) treated with imiquimod cream 5%: 12 case reports.

Lentigo maligna (LM) is an in situ variant of melanoma. Although LM has the potential for invasion, it often has a greatly protracted radial growth phase and may remain indolent for years. The current standard of care is surgical excision, but this often results in substantial morbidity; thus, nonsurgical approaches continue to be investigated. Imiquimod cream 5% is an immunomodulatory agent that previously has been reported to successfully eradicate LM. We evaluated the treatment course of topical imiquimod in 12 patients with LM. Data from patients with biopsy-proven LM were collected retrospectively, reviewed, and summarized. Patients ranged in age from 54 to 83 years. Most patients chose imiquimod cream as their initial form of treatment; however, other patients had a history of LM recurrence after excision or had positive histologic margins at the time of excision. Initial application regimens varied from 2 to 7 times weekly. The average duration of treatment was 15.7 weeks but ranged from 7 to 44 weeks. Results of posttreatment biopsies of the most clinically suspicious areas in 6 patients showed histologic clearance; 2 patients demonstrated single atypical melanocytes and 4 patients demonstrated clinical clearance without histologic confirmation. These findings suggest that imiquimod cream 5% may be an effective alternative treatment for LM.

Skin Cancer Risk Is Modified by KIR/HLA Interactions That Influence the Activation of Natural Killer Immune Cells.

Natural killer (NK)-cell phenotype is partially mediated through binding of killer-cell immunoglobulin-like receptors (KIR) with HLA class I ligands. The KIR gene family is highly polymorphic and not well captured by standard genome-wide association study approaches. Here, we tested the hypothesis that variations in KIR gene content combined with HLA class I ligand status is associated with keratinocyte skin cancers using a population-based study of basal cell carcinoma (BCC) and squamous cell carcinomas (SCC). We conducted an interaction analysis of KIR gene content variation and HLA-B (Bw4 vs. Bw6) and HLA-C (C1 vs. C2). KIR centromeric B haplotype was associated with significant risk of multiple BCC tumors (OR, 2.39; 95% confidence interval, 1.10-5.21), and there was a significant interaction between HLA-C and the activating gene KIR2DS3 for BCC (Pinteraction = 0.005). Furthermore, there was significant interaction between HLA-B and telomeric KIR B haplotype (containing the activating genes KIR3DS1 and KIR2DS1) as well as HLA-B and the activating KIR gene KIR2DS5 (Pinteraction 0.001 and 0.012, respectively). Similar but greatly attenuated associations were observed for SCC. Moreover, previous in vitro models demonstrated that p53 is required for upregulation of NK ligands, and accordingly, we observed there was a strong association between the KIR B haplotype and p53 alteration in BCC tumors, with a higher likelihood that KIR B carriers harbor abnormal p53 (P < 0.004). Taken together, our data suggest that functional interactions between KIR and HLA modify risks of BCC and SCC and that KIR encoded by the B genes provides selective pressure for altered p53 in BCC tumors.

Cutaneous adnexal neoplasms.

Cutaneous adnexal tumors are a large and diverse group of tumors that are commonly classified according to their state of appendageal differentiation: eccrine, apocrine, follicular, and sebaceous. These tumors generally behave in a benign manner, but malignant types exist. Most adnexal tumors are not common enough to permit most practitioners to maintain a ready familiarity with them, but they also are not rare. We provide a brief review of the clinical, histopathologic, and other relevant features of some adnexal tumors we believe the practitioner has the greatest likelihood of seeing in daily service. We also enumerate criteria the practitioner can use to distinguish between tumors likely to behave in a benign rather than a malignant manner.