Clinical aspects of epidermodysplasia verruciformis

Detection of the prototype of a potential novel genus in the family Papillomaviridae in association with canine epidermodysplasia verruciformis

Epidermodysplasia verruciformis (EV) is a rare human genetic predisposition to develop flat warts, some of which subsequently undergo cancer transformation. Some human papillomaviruses (HPVs), i.e. HPV 5 and 8, have been associated with cancer development as a sequela of EV. As similar diseases have been observed in dogs, it was hypothesized that unknown canine papillomaviruses (CPVs) may exist and that they may be present in cases of canine EV. Consequently, DNA was extracted from a malignant lesion of a dog with EV and circular DNA was amplified by multiple-primed rolling-circle amplification (RCA). Indeed, sequence determination and analysis of the RCA-amplified and cloned DNA from a malignant canine EV lesion resulted in the detection and primary description of a third CPV (CPV3). Typical papillomavirus genes were identified, with deduced amino acid similarities ranging from 20 to 57 % for E1, E2, E6, E7, L1 and L2, respectively. According to the sequence of the L1 gene, which is used for papillomavirus classification, the new isolate meets the majority of criteria needed to declare detection of a novel genus among the papillomaviruses. Thus, CPV3 may represent the prototype of this novel genus. As the novel virus was found in a dog in association with lesions reminiscent of human EV, it should be interesting to test in the future whether this condition can be reproduced in experimental animals. If such were the case, a new model for EV could be established.

Cutaneous squamous cell carcinoma: a comprehensive clinicopathologic classification

Cutaneous squamous cell carcinoma (SCC) includes many subtypes with widely varying clinical behaviors, ranging from indolent to aggressive tumors with significant metastatic potential. However, the tendency for pathologists and clinicians alike is to refer to all squamoid neoplasms as generic SCC. No definitive, comprehensive clinicopathological system dividing cutaneous SCCs into categories based upon their aggressiveness has yet been promulgated. Therefore, we have proposed the following based upon the malignant potential of SCC variants, separating them into categories of low (< or = 2% metastatic rate), intermediate (3-10%), high (greater than 10%), and indeterminate behavior. Low-risk SCCs include SCC arising in actinic keratosis, HPV-associated SCC, tricholemmal carcinoma, and spindle cell SCC (unassociated with radiation). Intermediate-risk SCCs include adenoid (acantholytic) SCC, intraepidermal epithelioma with invasion, and lymphoepithelioma-like carcinoma of the skin. High-risk subtypes include de novo SCC, SCC arising in association with predisposing factors (radiation, burn scars, and immunosuppression), invasive Bowen's disease, adenosquamous carcinoma, and malignant proliferating pilar tumors. The indeterminate category includes signet ring cell SCC, follicular SCC, papillary SCC, SCC arising in adnexal cysts, squamoid eccrine ductal carcinoma, and clear-cell SCC. Subclassification of SCC into these risk-based categories, along with enumeration of other factors including tumor size, differentiation, depth of invasion, and perineural invasion will provide prognostically relevant information and facilitate the most optimal treatment for patients.

Cutaneous squamous cell carcinoma: a comprehensive clinicopathologic classification. Part one

Cutaneous squamous cell carcinoma (SCC) includes many subtypes with widely varying clinical behaviors, ranging from indolent to aggressive tumors with significant metastatic potential. However, the tendency for pathologists and clinicians alike is to refer to all squamoid neoplasms as generic SCC. No definitive, comprehensive clinicopathological system dividing cutaneous SCCs into categories based upon their aggressiveness has yet been promulgated. Therefore, we have proposed the following based upon the malignant potential of SCC variants, separating them into categories of low (< or = 2% metastatic rate), intermediate (3-10%), high (greater than 10%), and indeterminate behavior. Low-risk SCCs include SCC arising in actinic keratosis, HPV-associated SCC, tricholemmal carcinoma, and spindle cell SCC (unassociated with radiation). Intermediate-risk SCCs include adenoid (acantholytic) SCC, intraepidermal epithelioma with invasion, and lymphoepithelioma-like carcinoma of the skin. High-risk subtypes include de novo SCC, SCC arising in association with predisposing factors (radiation, burn scars, and immunosuppression), invasive Bowen's disease, adenosquamous carcinoma, and malignant proliferating pilar tumors. The indeterminate category includes signet ring cell SCC, follicular SCC, papillary SCC, SCC arising in adnexal cysts, squamoid eccrine ductal carcinoma, and clear-cell SCC. Subclassification of SCC into these risk-based categories, along with enumeration of other factors including tumor size, differentiation, depth of invasion, and perineural invasion will provide prognostically relevant information and facilitate the most optimal treatment for patients.

HPV-associated skin disease

Human papillomaviruses (HPVs) are DNA tumour viruses that induce hyperproliferative lesions in cutaneous and mucosal epithelia. The relationship between HPV and non-melanoma skin cancer (NMSC) is important clinically since NMSC is the most common form of malignancy among fair-skinned populations. It is well established that solar ultraviolet (UV) irradiation is the major risk factor for developing NMSC, but a pathogenic role for HPV in the development of NMSC has also been proposed. Recent molecular studies reveal a likely role for HPV infection in skin carcinogenesis as a co-factor in association with UV. This review summarizes the literature describing these data, highlights some of the important findings derived from these studies, and speculates on future perspectives.

Association of p53 arginine polymorphism with skin cancer

BACKGROUND

The presence of arginine at codon 72 in p53 protein is proposed to be a genetic risk factor in human papillomavirus (HPV)-related carcinogenesis.

OBJECTIVE

To study the prevalence of p53 polymorphism at codon 72 in skin biopsies of epidermodysplasia verruciformis (EV) patients compared to DNA samples from healthy individuals.

PATIENTS AND METHODS

DNA samples extracted from normal skin and tumor biopsies of 22 Brazilian patients with EV and blood samples from 27 healthy Brazilian individuals were studied for p53 codon 72 polymorphisms using restriction fragment length polymorphism (RFLP) analysis.

RESULTS

All EV patients with the malignant form of EV were homozygous for arginine (Arg/Arg) at codon 72 of the p53 gene, in contrast to none with the benign form (P < 0.0001).

CONCLUSIONS

p53 arginine polymorphism is likely to be associated with the development of skin malignancies in EV patients from Brazil.