Elevated chromosome aberration frequency after X-ray exposure of cultured fibroblasts derived from patients with porokeratosis

The Malignancy Potential of Porokeratosis: A Single-Center Retrospective Study

Background Porokeratosis (PK) is a rare group of keratinization disorders. While the overall prognosis of PK is favorable, malignant transformation of PK to skin cancer has been reported in 6.9% to 11.6% of the cases. Prior estimates of malignant transformation of PK have been based on reviews of published cases, which introduces possible publication bias. We aim to eliminate this potential bias and quantify the characteristics, risk factors, and malignancy potential of PK. Methodology A single-center retrospective chart review of patients with a diagnosis of PK was conducted. Results In this study, 6.4% to 16.4% of histologically confirmed PK lesions demonstrated malignant transformation. A higher proportion of disseminated superficial actinic porokeratosis (DSAP) cases (as high as 29.3%) showed malignant transformation compared to PK of Mibelli (as high as 6.0%). Out of the two cases of linear PK, both demonstrated malignant transformation. Conclusions In summary, PKs are at risk for malignant transformation, and patients with DSAP and linear PK, in particular, should receive more long-term surveillance. Limitations of this study include the inability to control for confounding factors due to the retrospective nature and the small size of our cohort.

Radiation-induced micronucleus induction in lymphocytes identifies a high frequency of radiosensitive cases among breast cancer patients: a test for predisposition?

Enhanced sensitivity to the chromosome-damaging effects of ionizing radiation is a feature of many cancer-predisposing conditions. We previously showed that 42% of an unselected series of breast cancer patients and 9% of healthy control subjects showed elevated chromosomal radiosensitivity of lymphocytes irradiated in the G2 phase of the cell cycle. We suggested that, in addition to the highly penetrant genes BRCA1 and BRCA2, which confer a very high risk of breast cancer and are carried by about 5% of all breast cancer patients, there are also low-penetrance predisposing genes carried by a much higher proportion of breast cancer patients, a view supported by recent epidemiological studies. Ideally, testing for the presence of these putative genes should involve the use of simpler methods than the G2 assay, which requires metaphase analysis of chromosome damage. Here we report on the use of a simple, rapid micronucleus assay in G0 lymphocytes exposed to high dose rate (HDR) or low dose rate gamma-irradiation, with delayed mitogenic stimulation. Good assay reproducibility was obtained, particularly with the HDR protocol, which identified 31% (12 out of 39) of breast cancer patients compared with 5% (2 out of 42) of healthy controls as having elevated radiation sensitivity. In the long term, such cytogenetic assays may have the potential for selecting women for intensive screening for breast cancer.

Porokeratosis and cutaneous malignancy. A review

BACKGROUND

Porokeratosis is a disorder of epidermal keratinization manifested clinically by a raised border and histologically by a cornoid lamella. While cutaneous malignancy has been reported to arise in porokeratosis, the risk remains unknown. In the past it has been associated with a history of radiation therapy.

OBJECTIVE

The purpose of this study is to estimate the frequency of cutaneous malignancy arising in porokeratosis and define those patients who are at highest risk.

METHODS

All cases in the English language literature in the last 30 years were reviewed.

RESULTS

Twenty-one (7.5%) of 281 cases reported revealed a malignancy arising within porokeratosis. Large lesions, those of long-standing duration, and the linear type were at greatest risk. Radiation therapy was an infrequently identified risk factor.

CONCLUSION

Porokeratosis is a premalignant condition, with certain groups of patients at greatest risk for malignant transformation.