Overexpression of p53 in disseminated superficial actinic porokeratosis with and without malignant degeneration

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

“…While DNA ploidy was determined from lesional epidermis it could not be determined from nonlesional epidermis in many porokeratosis types [8]. DNA ploidy has been observed in a PPPD case with a similar research method [9]. According to some authors, ionizing radiation or sunlight is not thought to be the main factor even in immunosuppression states for the progression of malignancy in porokeratosis cases [8, 22].…”

“…Chromosomal instability and abnormal DNA ploidy were found in these patients [7, 8]. Also, TP53 overexpression has been reported in several types of porokeratosis (plaque, disseminated superficial actinic, disseminated superficial, linear and giant porokeratosis) [9, 10, 11, 12, 13, 14]. We examined TP53 mutations of exons 5–6, 7 and 8 in our patient, who has PPPD, a rare type.…”

Porokeratosis and malignant melanoma: A causal or incidental association?

“…showed an overexpression of p53 in the nuclei of, mainly, basal keratinocytes within or under the cornoid lamella. [ 4 ] The increase of p53 levels under the cornoid lamella could be associated with malignant transformation or it is only a protective reaction following intense UV exposure, as previously reported? [ 3 ]…”

“…The association of porokeratosis and malignant neoplasm is estimated between 6.9% and 11.6%. [ 2 3 4 ] The most frequent tumors identified are “in situ” and invasive squamous cell carcinoma, and less-frequent basal cell carcinoma. [ 2 3 4 ] The association with melanoma had been reported once by Maubec and colleagues.…”

Premature apoptosis of keratinocytes and the dysregulation of keratinization in porokeratosis

“…Recently, increased expression of the p53 tumour suppressor gene product has been found in keratinocytes under or adjacent to cornoid lamella in all subtypes of porokeratosis 10–12 . The principal function of p53 is at the G1 check point in the cell cycle 13,14 .…”