Keratinocytic Lesions Research Articles

Body site locations of basal cell carcinoma, squamous cell carcinoma and actinic keratosis in patients referred to the Waikato District Health Board teledermoscopy clinic.

Introduction Basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and actinic keratosis (AK) are usually located on sun-exposed areas of the body. Aims Our main aims were to identify the common body site locations of BCC, SCC and AK in patients attending the Waikato District Health Board teledermoscopy clinic, also known as the Waikato Virtual Lesion Clinic, as well as to analyse whether the distribution of location changes with age and sex. Methods This is a retrospective study where the body site location of 3272 keratinocytic lesions was determined and analysed in 1864 patients attending the Waikato District Health Board teledermoscopy clinics between 2010 and 2021. Results All three types of lesion were most commonly located in the head and neck region (40.9% of BCCs, 38% of SCCs, 83.2% of AKs), followed by 26.8% on the trunk for BCC, 32.3% on the lower extremities for SCC, and 11.6% on the upper extremities for AK. Discussion Our findings of body site locations for keratinocytic lesions were consistent with other studies. Patients were commonly diagnosed with multiple keratinocytic lesions.

Analysis of BCL-2 protein expression in keratinocytic hyperproliferative lesions

Apoptosis regulates keratinocytic proliferation and formation of stra-tum corneum in skin and is regulated by proteins like BCL-2 which con-trols cell survival and p53 which regulates cell death. Dysfunctional apoptosis plays an important role in development of hyperproliferative skin disorders including non-tumorigenic, pre-tumorigenic and tumor-igenic conditions. Therefore, we conducted a study to analyze the ex-pression pattern of apoptosis regulating protein BCL-2 in keratinocytic hyperproliferative lesions. The aim of this study was to evaluate and compare BCL-2 expression in various non-tumorigenic, pre-tumorigenic and tumorigenic keratinocytic hyperproliferative lesions. Skin biopsies of hyperproliferative keratinocytic lesions were studied from October 2018 to September 2020. The cases were categorized into 3 groups based on histological diagnosis (non-tumorigenic, pre-tumorigenic and tumorigenic). Following this, IHC for BCL-2 was performed on all cases using standard protocol. Tumorigenic lesions included 7 cases of SCC, pre-tumorigenic included 6 cases of seboherric keratosis, 2 cas-es of condyloma acuminata, 1 case of epidermodysplasia verruciform-is and 1 case of actinic keratosis, while the remaining 35 cases were non-tumorigenic, including psoriasis (6 cases), verruca vulgaris (4 cas-es), lichen planus (12 cases), chronic dermatitis (9 cases) and lichen simplex chronicus (4 cases). BCL-2 average weighted score in non-tumorigenic lesions was (1.25±1.13) as compared with pre-tumorigenic and tumorigenic lesions (5.30±3.32) and thus showing a significant p value (p<0.001). To conclude, significantly increased BCL-2 expression in neoplastic lesions shows that increased cell survival may contribute to neoplastic transformation.

Loss of dynamin-related protein 1 (Drp1) does not affect epidermal development or UVB-induced apoptosis but does accelerate UVB-induced carcinogenesis

BackgroundMitochondrial morphology is controlled by fission and fusion. Dynamin-related protein 1 (Drp1, dynamin-1-like protein (Dnml1)) regulates mitochondrial fission, which is associated with cell division and apoptosis. We previously reported that DRP1 is indispensable for cell growth in cutaneous squamous cell carcinoma. However, little is known about Drp1 in normal epidermis/keratinocytes. ObjectivesWe investigated the function of Drp1 in normal epidermis/keratinocytes. MethodsEpidermis-specific Drp1 knockout (EKO) mice were analyzed. ResultsEpidermal development in the EKO mice were indistinguishable from those in the wild-type (WT) mice. Ultrastructural analysis and immunohistochemistry revealed that the mitochondria of keratinocytes in the EKO mice were neither elongated nor constricted. Drp1 knockdown did not diminish the cell growth of normal human keratinocytes. Both in vivo and in vitro, UVB-induced apoptosis in the EKO epidermis and keratinocytes did not differ from that in the WT mice. In chronic UVB-irradiation, the loss of Drp1 sensitized the epidermis to the development of skin tumors. Clinically, DRP1 is expressed more highly in sun-exposed skin than in non-exposed skin in individuals under age 40, but not in those over age 60. ConclusionEKO mice demonstrate that Drp1 is dispensable for the development and apoptosis of the epidermis. Drp1 plays critical roles in malignant tumors; thus, the molecular machinery of mitochondrial dynamics involving Drp1 could be a novel therapeutic target for malignant keratinocytic lesions. On the other hand, the anti-tumorigenic role of Drp1 in chronic UVB-induced carcinogenesis need to be further investigated.

Expression of Minichromosome Maintenance Proteins in Actinic Keratosis and Squamous Cell Carcinoma.

Minichromosome maintenance (MCM) proteins are a group of proteins involved in DNA replication and cell-cycle regulation. Because they are associated with DNA through G1 into S phase, MCM proteins are potentially specific indicators of cell proliferation that could be valuable markers of dysplasia, and preinvasive and invasive malignant tumors. To analyze MCM protein expression patterns in actinic keratosis (AK), Bowen disease (BD), and cutaneous squamous cell carcinoma (SCC), we performed immunohistochemical staining of MCM2, -5, and -7 on tissue microarray blocks from 91 AK, 50 BD, and 174 SCC samples. The distribution and semiquantitatively assessed number of positive cells were analyzed in relation to the type of the lesion and the SCC prognostic parameters (grade, diameter, and thickness). Basal expression of all 3 proteins was observed more frequently in AK, whereas the distribution in BD was predominantly diffuse (P<0.001). All 3 proteins showed peripheral distribution in most well-differentiated SCC and diffuse distribution in poorly differentiated tumors (P<0.001). Using the 50% cut-off value, there was a statistically significant difference among AK, BD, and SCC (P<0.001). In addition, all MCM proteins showed highly significant differences (P<0.001) between well-differentiated SCC and both moderately and poorly differentiated SCC. The diffuse distribution and 50% cut-off value of positive cells revealed statistically significant associations of all MCM proteins with SCC thicker than 6 mm. Our results suggest a role for MCM proteins in the progression of in situ keratinocytic lesions and their association with high-risk features in SCC.

Proliferation, apoptosis, and survivin expression in a spectrum of melanocytic nevi

Apoptosis is important for maintenance of tissue homeostasis and often dysregulated in cutaneous neoplasms. The apoptosis inhibitor survivin is expressed in melanoma and non-melanoma skin cancers and benign keratinocytic lesions. Its expression has not been studied in melanocytic nevi. We determined the expression pattern of survivin in benign melanocytic nevi in comparison to markers of proliferation and apoptosis. Six cases of each of the following melanocytic nevi were retrieved from a dermatopathology archive: compound dysplastic nevus, intradermal nevus, compound nevus, neurotized intradermal nevus, and Spitz nevus. Survivin expression was evaluated by in situ hybridization. Apoptotic and proliferation indices were calculated by counting immunoreactive cells in terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling and proliferating cell nuclear antigen immunostained sections, respectively. All nevi, regardless of histologic type, expressed survivin. Compound melanocytic lesions expressed survivin in both epidermal and dermal compartments. The apoptotic rate was low for dysplastic, compound, and Spitz nevi, and apoptotic cells were not identified in any neurotized nevus. The proliferative index was highest for Spitz nevi, while all other nevi demonstrated rare positive cells. Survivin is consistently expressed in benign melanocytic lesions, while apoptotic cells are rarely identified, suggesting the dysregulation of apoptotic pathways with the accumulation of cells in these neoplasms.

Analysis of p53 and bcl‐2 protein expression in the non‐tumorigenic, pretumorigenic, and tumorigenic keratinocytic hyperproliferative lesions

The hyperproliferative keratinocytic lesions encompass a wide range of non-tumorigenic, pretumorigenic, and tumorigenic conditions. The aim of this work was to examine the expression patterns of apoptosis-linked molecules (bcl-2 and p53) in these lesions. Immunoperoxidase staining methods were applied to analyze p53 and bcl-2 protein expression in a total of 66 cases, including 12 squamous cell carcinomas (both in situ and invasive SCC), 11 actinic keratoses (AK), 13 psoriasis vulgaris (PV), eight verruca vulgaris (VV), six chronic dermatitis (CD), five seborrheic keratosis (SK), four lichen planus (LP), three epidermodysplasia verruciformis (EDV), two condyloma acuminata (CA), two lichen simplex chronicus (LSC), and 10 specimens from normal skin. As compared to normal skin (0.70 +/- 0.26), the bcl-2 average weighted scores in the non-tumorigenic (0.76 +/- 0.16), pretumorigenic (1.45 +/- 0.28), and tumorigenic lesions (2.83 +/- 0.50 and 2.92 +/- 0.50 for in situ and invasive SCC, respectively) showed significant up-regulation (p = 0.001). In the non-tumorigenic lesions, the bcl-2 expression values decreased in the following order: SK > EDV > CD > LP > CA > PV > VV (1.40 +/- 0.24 > 1.33 +/- 0.67 > 0.83 +/- 0.40 > 0.67 +/- 0.21 > 0.50 +/- 0.20 > 0.46 +/- 0.22 > 0.13 +/- 0.01, respectively). As compared to normal skin (1.10 +/- 0.23), the p53 average weighted scores in the non-tumorigenic (1.86 +/- 0.18), pretumorigenic (3.64 +/- 0.53), and tumorigenic lesions (5.00 +/- 1.00 and 5.08 +/- 0.86 for in situ and invasive SCC, respectively) showed significant up-regulation (p = 0.021). In the non-tumorigenic lesions, p53 average weighted scores decreased in the following order: SK > PV > CA > LP > CD > VV > EDV (3.20 +/- 0.49 > 2.38 +/- 0.27 > 2.0 +/- 0.0 > 1.83 +/- 0.48 > 1.0 +/- 0.37 > 1.0 +/- 0.33 > 1.0 +/- 0.0, respectively). There was a positive correlation between bcl-2 and p53 protein expression in normal skin (r = 0.966, p = 0.0001), non-tumorigenic (r = 0.775, p = 0.0001), pretumorigenic (r = 0.830, p = 0.001), and tumorigenic lesions (r = 0.757, p = 0.003). Bcl-2 and p53 proteins are altered in the keratinocytic hyperproliferative lesions. Determination of whether these alterations reflect underlying gene mutations will require further investigations.

Altered basic fibroblast growth factor expression in common epidermal neoplasms: Examination with in situ hybridization and immunohistochemistry

Background: The fibroblast growth factor family consists of acidic fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF), and Kaposi fibroblast growth factor (kFGF). The distribution of these growth factors in skin disease has not been determined. Objective: The purpose of this study was to determine the distribution of these growth factors in keratinocytic lesions and normal skin. Methods: Skin sections from common disorders of keratinocytes were examined by in situ hybridization with specific probes for aFGF, bFGF, and kFGF, and immunohistochemistry. Results: Of the growth factors studied, only bFGF was present in skin. bFGF messenger RNA was highly expressed in both normal epidermis and benign and malignant epithelial neoplasms. In normal skin, bFGF was expressed predominantly in a suprabasal fashion, whereas in epithelial neoplasms, homogeneous high-level expression of bFGF was observed. Conclusion: bFGF is the primary member of the fibroblast growth factor expressed in the skin. The source of synthesis of bFGF is keratinocytes. Immunoreactivity for bFGF appears to be primarily confined to upper layers of the epidermis in normal skin, but is expressed at all layers of the epidermis in both benign and malignant neoplastic conditions. Genetic changes that promote epithelial tumors may also promote translation of bFGF messenger RNA into protein. Specific inhibition of bFGF activity may have application in the treatment of common skin diseases. (J Am Acad Dermatol 2000;42:973–7.)

Altered basic fibroblast growth factor expression in common epidermal neoplasms: Examination with in situ hybridization and immunohistochemistry

Background: The fibroblast growth factor family consists of acidic fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF), and Kaposi fibroblast growth factor (kFGF). The distribution of these growth factors in skin disease has not been determined. Objective: The purpose of this study was to determine the distribution of these growth factors in keratinocytic lesions and normal skin. Methods: Skin sections from common disorders of keratinocytes were examined by in situ hybridization with specific probes for aFGF, bFGF, and kFGF, and immunohistochemistry. Results: Of the growth factors studied, only bFGF was present in skin. bFGF messenger RNA was highly expressed in both normal epidermis and benign and malignant epithelial neoplasms. In normal skin, bFGF was expressed predominantly in a suprabasal fashion, whereas in epithelial neoplasms, homogeneous high-level expression of bFGF was observed. Conclusion: bFGF is the primary member of the fibroblast growth factor expressed in the skin. The source of synthesis of bFGF is keratinocytes. Immunoreactivity for bFGF appears to be primarily confined to upper layers of the epidermis in normal skin, but is expressed at all layers of the epidermis in both benign and malignant neoplastic conditions. Genetic changes that promote epithelial tumors may also promote translation of bFGF messenger RNA into protein. Specific inhibition of bFGF activity may have application in the treatment of common skin diseases. (J Am Acad Dermatol 2000;42:973–7.)

Simultaneous occurrence of multiple melanoma in situ on sun-damaged skin (lentigo maligna), solar lentigo and labial melanosis: the value of dermoscopy in diagnosis

We report on a patient developing simultaneous occurrence of lentigo maligna lesions, solar lentigines and an extensive melanosis of the oral mucosa. Diagnostically, epiluminescence microscopy had a relevant role in the preoperative assessment and selection of suspicious pigmented lesions, as the lesions histologically labelled as lentigo maligna and solar lentigo were clinically indistinguishable. We review the clinical, dermoscopic and histopathologic differential diagnosis of solar lentigo, malignant lentigo and mucosal melanosis with other melanocytic and keratinocytic lesions and discuss the possible relationship between these entities.

Simultaneous occurrence of multiple melanoma in situ on sundamaged skin (lentigo maligna), solar lentigo and labial melanosis: the value of dermoscopy in diagnosis

We report on a patient developing simultaneous occurrence of lentigo maligna lesions, solar lentigines and an extensive melanosis of the oral mucosa. Diagnostically, epiluminescence microscopy had a relevant role in the preoperative assessment and selection of suspicious pigmented lesions, as the lesions histologically labelled as lentigo maligna and solar lentigo were clinically indistinguishable. We review the clinical, dermoscopic and histopathologic differential diagnosis of solar lentigo, malignant lentigo and mucosal melanosis with other melanocytic and keratinocytic lesions and discuss the possible relationship between these entities.

Less expression of cyclin E in cutaneous squamous cell carcinomas than in benign and premalignant keratinocytic lesions.

In a previous study, we showed that overexpression of cyclin D, a G1 cyclin, is frequently associated with keratinocyte carcinogenesis as an early event. Another G1 cyclin, cyclin E, was recently suggested to be a prognostic marker for breast cancer. In order to evaluate the role of cyclin E in human keratinocyte carcinogenesis, we analysed the expression of cyclin E by immunohistochemistry in normal skin, seborrheic keratosis (SK), keratoacanthoma (KA), actinic keratosis (AK), Bowen's disease (BD), basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Positive cells were seen rarely in normal epidermis, in 9 of 20 cases of SK, in 5 of 6 cases of KA, in 9 of 13 cases of AK and in all 27 cases of BD. Some of the cases of AK and BD had positive cells in the superficial epidermis, where atypicality is less obvious. In contrast, positive cells were seen in 4 of 25 cases of SCC and none of 15 cases of BCC. These results suggest that expression of cyclin E plays a role in the formation of benign and premalignant keratinocytic tumors, whereas down-regulation of cyclin E expression may be involved in carcinogenesis in human keratinocytes.

Localization of MGSA/GRO protein in cutaneous lesions.

Melanoma growth stimulatory activity (MGSA/GRO), a cytokine originally characterized as an autocrine growth factor for melanoma cells, is highly chemotactic for neutrophils and releases neutrophil elastase as well as other matrix-degrading enzymes. Previous work has demonstrated the presence of MGSA/GRO in melanocytic lesions and in the epidermal keratinocytes of non-lesional skin and psoriatic scale. Herein, MGSA/GRO localization was examined in a variety of human skin lesions exhibiting proliferative and/or differentiative disorders using immunohistochemical methods. Most lesions showed greater MGSA/GRO immunoreactivity in the more differentiated suprabasal keratinocytes of the stratum spinosum and stratum granulosum than in the stratum basalis, where the dividing basal cells are found. Hair follicles, sebaceous glands, and sweat glands were also frequently positive for MGSA/GRO. The highest level of immunoreactive MGSA/GRO in diseased epidermis was detected in verruca vulgaris, followed by psoriasis, keratoacanthoma, and squamous cell carcinoma. Detection of MGSA/GRO in basal cell carcinoma was variable, being present in the sclerosing variant and absent in the more common nodular variant. Melanocytic lesions stained less intensely for MGSA/GRO than keratinocytic lesions, where the levels of MGSA/GRO expression correlated with the inflammatory response and degree of keratinocyte differentiation.

Carcinogenesis in Porokeratosis

Porokeratoses are known to give rise to squamous and basal cell carcinomas. In this study, we examined 15 lesions of porokeratosis immunohistochemically for evidence of aberrant keratinization using several markers of keratinocyte (KC) maturation and differentiation, including involucrin, filaggrin, cytokeratins, and the growth activation marker psi-3. The staining patterns obtained were compared with several non-premalignant parakeratotic skin lesions including psoriasis, pityriasis rosea, pityriasis rubra pilaris, irritated seborrheic keratosis, atopic dermatitis, seborrheic dermatitis, and verruca vulgaris. The centers of porokeratoses stained in a pattern identical to that observed in other premalignant keratinocytic lesions including actinic keratoses, recessive dystrophic epidermolysis bullosa, and nonhealing wounds. KCs beneath the cornoid lamella (CL) stained in a pattern similar to that observed in squamous cell carcinomas. KCs peripheral to the CL in the epidermis showed a normal staining pattern. The control non-premalignant parakeratotic lesions displayed a variety of staining patterns, but none showed a pattern identical to that observed in porokeratosis. The failure of KCs in porokeratoses to mature and differentiate normally may be related to the increased incidence of carcinomas associated with these lesions.

Malignant melanoma in situ

There is general agreement that there are lesions which should be diagnosed as malignant melanoma in situ. The biologic behavior of the intraepidermal component of superficial spreading melanoma (the radial growth phase) has been demonstrated to have significantly different properties than those of the cells in the vertical growth phase. The central controversies regarding malignant melanoma in situ relate to the criteria for diagnosing melanoma and whether there are atypical melanocytic lesions which are neither nevi nor melanoma. I propose that reliable and reproducible objective criteria for melanoma have not been developed; rather, dermatopathologists use differing subjective criteria which result in diagnostic agreement in the vast majority of lesions. The controversy is over those lesions which are classified as melanoma by one set of criteria and not by others. I am also a proponent of the diagnosis of atypical melanocytic lesions, and have suggested an analogy to keratinocytic lesions in which this concept is well established. Studies of the sensitivity and specificity of the correlation between clinical and histologic features and the biologic behavior of melanocytic lesions are necessary to resolve these issues.