Lack of <i>TP53</i> Mutations in a Case of Porokeratosis palmaris, plantaris et disseminata

Abstract

A 73-year-old man with porokeratosis palmaris, plantaris et disseminata is presented. He had punctate, guttate and annular hyperkeratotic papular lesions widespread on his body with thorn-like hyperkeratosis on the palms and soles. Lesional skin did not show mutations of TP53 exons 5–6, 7, 8.

Porokeratosis: present concepts

“…An increased oncogenic potential as a result of a high rate of abnormal DNA ploidy has been found in lesions of PPPD, 94,95 and by certain phenotypic features indicative of malignant transformation such as p53 overexpression in the keratinocytes near the cornoid lamella in lesions of all types of PK and throughout the epidermis in bowenoid lesions 96,97 . This overexpression of the molecule is not related to gene mutation 98,99 . No overexpression of p53 was seen in keratinocytes underlying the cornoid lamella 79 .…”

Gene expression profiling of porokeratosis demonstrates similarities with psoriasis

“…5 Additional studies have revealed a variety of genetic and molecular abnormalities within PK lesions including increased apoptosis, DNA aneuploidy, loss of loricrin expression, increased immunohistochemical staining for p53, and decreased staining for p21 and mdm2. [6][7][8][9][10][11][12] Interestingly, these studies have demonstrated increased p53 expression in porokeratotic lesions, but, it appears that the increased p53 levels do not correlate with a mutation in the p53 gene. Immunohistochemical studies on PK lesions examining the expression of keratinocyte differentiation markers such as cytokeratins, involucrin, filaggrin, and psi-3 in PK lesions have supported the hypothesis that PK is closer to SCC at the molecular level than reactive conditions such as psoriasis.…”

“…A review of 281 PK cases reported between 1964 and 1994 demonstrated the following rates of SCC arising within PK lesions: Mibelli, 7.6%; DSAP, 3.4%; linear, 19%; and PPPD 9.5% 5 . Additional studies have revealed a variety of genetic and molecular abnormalities within PK lesions including increased apoptosis, DNA aneuploidy, loss of loricrin expression, increased immunohistochemical staining for p53, and decreased staining for p21 and mdm2 6–12 . Interestingly, these studies have demonstrated increased p53 expression in porokeratotic lesions, but, it appears that the increased p53 levels do not correlate with a mutation in the p53 gene.…”

p53 alterations in porokeratosis

“…To date, only two studies of p53 at the gene level have been reported 20,21 on PK. Both showed that p53 overexpression present in most porokeratotic specimens did not relate to gene mutation.…”