Mutations in the TP53 gene in human malignant melanomas derived from sun-exposed skin and unexposed mucosal membranes.

Mutations in the p53 tumour suppressor gene ( ) have been linked to several types of cancer. We therefore investigated whether such mutations occur in malignant melanomas and, if so, whether they are linked to ultraviolet (sun) light exposure. For the first time, mutations in mucosal membranes and adjacent tissues shielded from sunlight were compared with those in cutaneous melanomas from sun-exposed skin. Archival tissues were obtained from 35 patients with a primary melanoma taken from unexposed mucosal areas and from 34 patients with a primary melanoma located in chronically sun-exposed head and neck skin. was characterized by means of polymerase chain reaction amplification and single-strand conformation polymorphism assay followed by nucleotide sequencing. The results showed that 17.6% of the primary cutaneous and 28.6% of the primary mucosal melanomas had point mutations in. Among the cutaneous melanomas, one showed three mutations in exon 7, and one had two mutations in exon 5; the mutation was in the same allele in both cases. One mucosal melanoma had two mutations in exon 7, both in the same allele, and another had two mutations, one in exon 7 and one in intron 6, both in the same allele. C<--T mutations at dipyrimidine sites, considered fingerprints for ultraviolet light-induced mutations, were about equally distributed among patients with melanomas from chronically sun-exposed areas (six out of nine; 67%) and those with melanomas from unexposed mucosal areas and adjacent skin (eight out of 14; 57%). Our data, demonstrating the presence of such mutations even in melanomas from mucosal membranes, clearly suggest that factors other than, or additional to, ultraviolet radiation are operational in the induction of mutations in melanomas.

Malignant melanoma of the vulva in a nationwide, 25-year study of 219 Swedish females: clinical observations and histopathologic features.

BACKGROUND: Because the clinical and histopathologic features of vulvar melanoma had not been characterized completely in a large, homogeneous population, the authors retrospectively analyzed all such patients recorded in Sweden during a 25-year period. METHODS: The Swedish National Cancer Registry opened its records to the authors for review of all 219 females with primary vulvar melanoma reported from 1960 to 1984. Histopathologic specimens and clinical histories of the 198 patients who qualified for this study were reanalyzed and the tumors rigorously subtyped. RESULTS: Macroscopically amelanotic tumors were observed in 27% of patients, predominantly in glabrous skin; the clitoral area and labia majora were the most common primary sites. Of all melanomas, 46% emerged in glabrous skin, 12% emerged in hairy skin, and 35% extended to both areas. On average, approximately 2.5 times more melanomas appeared in the vulva than on the whole body surface. Overall, 57% were of the mucosal lentiginous (MLM) type, 22% were nodular melanomas (NMs), 12% were unclassified, and only 4% were superficial spreading melanomas (SSMs); this was the reverse of the order observed for cutaneous melanoma. Almost all vulvar melanomas underwent a vertical growth phase; other common features were marked thickness and ulceration, particularly in the glabrous skin. Preexisting nevi occurred in 11 cases, all in hairy skin, and 71% in conjunction with SSM but only 4% with MLM. CONCLUSIONS: Several clinical and histopathologic features indicated that the natural history of vulvar melanomas is at variance with that of cutaneous melanomas. Because preexisting nevi, which are often considered a precursor to melanoma, were significantly linked to SSM and only in the vulvar hairy skin, melanomas in the glabrous skin apparently emerged de novo.

Malignant melanoma of the vulva in a nationwide, 25-year study of 219 Swedish females: predictors of survival.

BACKGROUND: In an epidemiologic study of 219 Swedish females with vulvar melanoma, the authors previously established the incidence of this disease as 0.19 per 100,000 women, with a 3% annual decrease from 1960 to 1984 and a 5-year relative survival rate of 47%. After reviewing the medical histories of all of the 219 patients, the authors documented their precise clinical and histopathologic features, which, along with treatment, are assessed herein as predictors of survival. METHODS: Of 219 consecutive cases of vulvar melanoma collected from the Swedish National Cancer Registry, 21 were excluded because of inadequate data. Clinical and histopathologic materials from the remaining 198 cases were then reexamined. With a clinical three-stage system, lesion types and treatment modalities were assessed as survival factors in univariate and multivariate analyses. RESULTS: In univariate analysis, significant predictors of survival for patients at Stage I were tumor thickness, ulceration, number of mitoses, macroscopic amelanosis, preexisting nevi, extent of tumor invasion (lateral labia majora), and patient age. The mode of treatment was not significant. In multivariate analysis, staging (Stage I vs. II and III) and tumor thickness were independent predictors of survival. For Stage I only, tumor thickness, ulceration, and clinical amelanosis independently predicted survival time. CONCLUSIONS: To the authors' knowledge, this is the largest series of patients with vulvar melanoma ever reviewed, and an ethnically homogeneous and nationwide female population is represented. In this series, clinical stage, macroscopic amelanosis, and tumor characteristics such as tumor thickness and ulceration, rather than treatment mode, were the best factors for predicting the outcome of these patients.