Expression of p53 in the evolution of squamous cell carcinoma: Correlation with the histology of the lesion

Grading differentiation in cutaneous squamous cell carcinoma: a review of the literature

Poor differentiation is strongly associated with poor outcomes in cutaneous squamous cell carcinoma (CSCC). In addition, the National Comprehensive Cancer Network (NCCN) guidelines designate poorly differentiated tumors as "very high risk". Despite its clear prognostic implications, there is no standardized grading system for CSCC differentiation in common use today. CSCC differentiation is graded inconsistently by both dermatopathologists and Mohs surgeons, and reliability studies have demonstrated suboptimal inter- and intra-rater reliability in both of these groups. The absence of a standardized and reliable grading system has impeded the use of differentiation in CSCC staging, despite its apparent correlation with disease outcomes. We performed a comprehensive review of the literature summarizing historical CSCC differentiation grading systems, as well as grading systems in non-cutaneous head and neck SCC as a point of reference. Relevant articles were identified by searching Embase and PubMed, as well as by reviewing reference lists for additional articles and histology textbook excerpts. CSCC grading systems that were identified and summarized include the historical Broders system, the World Health Organization system, the College of American Pathologists' system, and a system described by a 2023 Delphi consensus panel of dermatopathologists.

MiR-199a-3p Induces Mesenchymal to Epithelial Transition of Keratinocytes by Targeting RAP2B

Cutaneous squamous cell carcinoma (CSCC) is an epidermal skin cancer that evolves from normal epidermis along several pre-malignant stages. Previously we found specific miRNAs alterations in each step along these stages. miR-199a-3p expression decreases at the transition to later stages. A crucial step for epithelial carcinoma cells to acquire invasive capacity is the disruption of cell-cell contacts and the gain of mesenchymal motile phenotype, a process known as epithelial-to-mesenchymal transition (EMT). This study aims to study the role of decreased expression of miR-199a-3p in keratinocytes' EMT towards carcinogenesis. First, we measured miR-199a-3p in different stages of epidermal carcinogenesis. Then, we applied Photoactivatable Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation (PAR-CLIP) assay to search for possible biochemical targets of miR-199a-3p and verified that Ras-associated protein B2 (RAP2B) is a bona-fide target of miR-199a-3p. Next, we analyzed RAP2B expression, in CSCC biopsies. Last, we evaluated possible mechanisms leading to decreased miR-199a-3p expression. miR-199a-3p induces a mesenchymal to epithelial transition (MET) in CSSC cells. Many of the under-expressed genes in CSCC overexpressing miR-199a-3p, are possible targets of miR-199a-3p and play roles in EMT. RAP2B is a biochemical target of miR-199a-3p. Overexpression of miR-199a-3p in CSCC results in decreased phosphorylated focal adhesion kinase (FAK). In addition, inhibiting FAK phosphorylation inhibits EMT marker genes' expression. In addition, we proved that DNA methylation is part of the mechanism by which miR-199a-3p expression is inhibited. However, it is not by the methylation of miR-199a putative promoter. These findings suggest that miR-199a-3p inhibits the EMT process by targeting RAP2B. Inhibitors of RAP2B or FAK may be effective therapeutic agents for CSCC.

To treat or not to treat: PD-L1 inhibitor-induced keratoacanthoma and squamous cell carcinoma

Keratoacanthoma (KA) and squamous cell carcinoma (SCC) are rare side effects of programmed cell death ligand-1 (PD-L1) inhibitors that can disrupt therapy. There is no consensus on optimal treatment. We investigated the management strategy and factors influencing pathophysiology. An institutional cancer registry and literature search were used for this retrospective study. Only PD-L1-induced KA and SCC cases were included. Pathology specimens were stained with immune markers and management strategies were analyzed. Four cases were identified at our institution. Immunohistochemistry of atypical keratinocytes revealed PD-1/PD-L1 positivity, high p53, and low bcl-2 for all cases with differential expression of CD44 and beta-catenin for KA versus SCC. Nivolumab was continued or temporarily held with complete resolution. In addition, a literature search identified 30 additional cases of KA/SCC after PDL-1 inhibitor use. The most common treatment was excision/destruction followed by topical and/or intralesional corticosteroids. Therapy was definitely withheld in 22% of KA patients and in 9% of SCC cases. The expression of PD-L1 by atypical keratinocytes helps to explain the effects of nivolumab on the development of cutaneous neoplasms. The expression of immune markers provides mechanistic insights into pathophysiology. Management may be achieved with conservative therapy and without treatment interruption.

Prognostic Significance of RAS Mutations and P53 Expression in Cutaneous Squamous Cell Carcinomas

TP53 is considered the most commonly-altered gene in cutaneous squamous cell carcinoma (cSCC). Conversely, RAS mutations have been reported in a low percentage of cSCC. The objective of our study was to evaluate the frequency of p53 expression and RAS mutations in cSCC and correlate them with clinicopathological features and patient outcome. We performed immunohistochemistry for p53 and genetic profiling for RAS mutations in a retrospective series of cSCC. The predictive value of p53 expression, RAS mutations, and clinicopathological parameters was assessed using logistic regression models. The overall frequency of RAS mutations was 9.3% (15/162), and 82.1% of the cases (133/162) had p53 overexpression. RAS mutations rate was 3.2% (1/31) of in situ cSCCs and 10.7% (14/131) of invasive cSCCs. RAS mutations were more frequently associated with an infiltrative than an expansive pattern of invasion (p = 0.046). p53 overexpression was a predictor of recurrence in the univariate analysis. Our results indicate that RAS mutations associate with features of local aggressiveness. Larger studies with more recurrent and metastatic cSCCs are necessary to further address the prognostic significance of p53 overexpression in patients’ risk stratification.

The clinical course of actinic keratosis correlates with underlying molecular mechanisms

BACKGROUND

Actinic keratoses (AKs) are common premalignant skin lesions triggered by excessive ultraviolet exposure. The majority of AKs regress or persist, but some progress to squamous cell carcinomas. Biomarkers associated with their persistence, progression and regression have not been characterized.

OBJECTIVES

We performed skin biopsies in patients with extensive actinic damage to identify biomarkers that correlate with clinical progression and regression of AKs.

METHODS

This was an observational study of a cohort of patients with extensive actinic damage. AKs were mapped on a clear plastic template in 26 patients at months 3, 6, 9 and 11. Biopsies were taken from randomly selected, predetermined AKs and were evaluated for p53, E-cadherin, Snail, Slug and Twist. The study is registered at Clinicaltrials.gov: NCT00027976.

RESULTS

p53 exhibited greater expression in clinically apparent AKs (histological score 2·89 ± 1·45) than in regressed AKs (0·75 ± 0·96); P < 0·01. There was also significantly less membrane E-cadherin, the lack of which is a marker of epithelial-mesenchymal transition, in clinically apparent AKs (1·89 ± 1·81) than in sun-exposed skin (3·07 ± 1·75); P < 0·005. The E-cadherin transcription repressors Snail, Slug and Twist were increased in AKs compared with sun-exposed skin. A limitation of the study is that measurement of histological biomarkers was not a primary end point. In addition, patients were allowed to apply sunscreens.

CONCLUSIONS

At the molecular level, loss of E-cadherin and an increase in p53 are linked to the dynamic interplay between the persistence, progression and regression of AKs. What's already known about this topic? Actinic keratoses (AKs) are common dysplastic epidermal lesions that result from chronic and excessive ultraviolet exposure. Biomarkers associated with progression and regression of AK have not been characterized. What does this study add? Decreased E-cadherin and increased p53, Snail, Slug and Twist (E-cadherin transcription factors) were associated with progression from AK to nonmelanoma skin cancer. What is the translational message? Strategies targeting these molecules may be effective in reversing rising skin cancer rates. E-cadherin, p53, Snail, Slug and Twist are potential biomarkers that may be used to assess the efficacy of existing chemopreventive agents.

Alterations of microRNAs throughout the malignant evolution of cutaneous squamous cell carcinoma: the role of miR-497 in epithelial to mesenchymal transition of keratinocytes

Skin carcinogenesis is known to be a multi-step process with several stages along its malignant evolution. We hypothesized that transformation of normal epidermis to cutaneous squamous cell carcinoma (cSCC) is causally linked to alterations in microRNAs (miRNA) expression. For this end we decided to evaluate their alterations in the pathologic states ending in cSCC. Total RNA was extracted from formalin fixed paraffin embedded biopsies of five stages along the malignant evolution of keratinocytes towards cSCC: Normal epidermis, solar elastosis, actinic keratosis KIN1-2, advanced actinic keratosis KIN3 and well-differentiated cSCC. Next-generation small RNA sequencing was performed. We found that 18 miRNAs are overexpressed and 28 miRNAs are underexpressed in cSCC compared to normal epidermis. miR-424, miR-320, miR-222 and miR-15a showed the highest fold change among the overexpressed miRNAs. And miR-100, miR-101 and miR-497 showed the highest fold change among the underexpressed miRNAs. Heat map of hierarchical clustering analysis of significantly changed miRNAs and principle component analysis disclosed that the most prominent change in miRNAs expression occurred in the switch from 'early' stages; normal epidermis, solar elastosis and early actinic keratosis to the 'late' stages of epidermal carcinogenesis; late actinic keratosis and cSCC. We found several miRNAs with 'stage specific' alterations while others display a clear 'gradual', either progressive increase or decrease in expression along the malignant evolution of keratinocytes. The observed alterations focused in miRNAs involved in the regulation of AKT/mTOR or in those involved in epithelial to mesenchymal transition. We chose to concentrate on the evaluation of the molecular role of miR-497. We found that it induces reversion of epithelial to mesenchymal transition. We proved that SERPINE-1 is its biochemical target. The present study allows us to further study the pathways that are regulated by miRNAs along the malignant evolution of keratinocytes towards cSCC.

Cutaneous Squamous Cell Carcinomas of the Lower Extremities Show Distinct Clinical and Pathologic Features

Cutaneous squamous cell carcinomas mainly affect older, predominantly male patients. Most are due to chronic ultraviolet exposure, and associated with actinic keratoses. On the lower extremities, they occur more commonly in women. However, data on these tumors as a distinct group are scarce. We evaluated 61 squamous cell carcinomas of the lower extremities. Overall, 69% of patients were female. Mean age was 75 years. More than 90% of tumors were well differentiated, 3% showed perineural invasion, and none lymphovascular invasion. In all, 63.9% showed evidence of severe chronic sun damage. Associated actinic keratoses were identified in only 13% of cases. By contrast, 80% were associated with distinctive basal epidermal proliferations with a retiform growth pattern. These proliferations were evaluated immunohistochemically for keratinocyte stem cell markers, p53 and Notch1 in 15 cases. All cases were positive for cytokeratin 14, p53, and Notch1 (with variable intensity in the latter 2), and predominantly negative for cytokeratin 19. Interestingly, basal retiform proliferations were positive for cytokeratin 15 in 66% of cases. Fifteen head and neck squamous cell carcinomas were evaluated in comparison. Those lacked associated basal retiform proliferations except in 1 case. In contrast, 87% were associated with actinic keratoses and 100% with severe chronic sun damage. Actinic keratoses associated with head and neck tumors showed cytokeratin 15 staining only in 7% of cases (P = .003 compared with cytokeratin 15 in basal retiform proliferations associated with leg carcinomas). These findings support the hypothesis that lower extremity squamous cell carcinomas are distinct and may exhibit a pathogenesis less reliant on actinic damage.

p53 immunoexpression in stepwise progression of cutaneous squamous cell carcinoma and correlation with angiogenesis and cellular proliferation

Multistep carcinogenesis involves loss of function of tumor suppressor proteins such as p53 and induction of angiogenesis. Such mechanisms contribute to cutaneous squamous cell carcinoma progression and may be interconnected. We aimed to explore p53 immunoexpression in spectral stages of cutaneous squamous cell carcinoma and correlate expression to both neovascularization and cellular proliferation. We estimated the percentages of immunostained cells for p53 and Ki67 (proliferation marker) in three groups: 23 solar keratoses, 28 superficially invasive squamous cell carcinomas and 28 invasive squamous cell carcinomas. The Chalkley method was used to quantify the microvascular area by neoangiogenesis (CD105) immunomarker in each group. There was no significant difference for rate of p53- and Ki67-positive cells between groups. Significant positive correlation was found between the CD105 microvascular area and the rate of p53 positive cells in superficially invasive squamous cell carcinoma as well as between the rate of p53- and Ki67-positive cells in invasive squamous cell carcinoma. p53 and Ki67 immunoexpression did not increase with cutaneous squamous cell carcinoma progression. Neovascularization in the initial stage of invasion and proliferative activity in the frankly invasive stage were both associated with p53 immunoexpression. Loss of p53 tumor suppressor function through progressive steps may be directly involved in skin carcinogenesis.

Molecular pathology of skin neoplasms of the head and neck

CONTEXT

Skin neoplasms include the most common malignancies affecting humans. Many show an ultraviolet (UV)-induced pathogenesis and often affect the head and neck region.

OBJECTIVE

To review literature on cutaneous neoplasms that show a predilection for the head and neck region and that are associated with molecular alterations.

DATA SOURCES

Literature review.

CONCLUSIONS

Common nonmelanoma skin cancers, such as basal and squamous cell carcinomas, show a UV-induced pathogenesis. Basal cell carcinomas are characterized by molecular alterations of the Hedgehog pathway, affecting patched and smoothened genes. While squamous cell carcinomas show UV-induced mutations in several genes, driver mutations are only beginning to be identified. In addition, certain adnexal neoplasms also predominantly affect the head and neck region and show interesting, recently discovered molecular abnormalities, or are associated with hereditary conditions whose molecular genetic pathogenesis is well understood. Furthermore, recent advances have led to an increased understanding of the molecular pathogenesis of melanoma. Certain melanoma subtypes, such as lentigo maligna melanoma and desmoplastic melanoma, which are more often seen on the chronically sun-damaged skin of the head and neck, show differences in their molecular signature when compared to the other more common subtypes, such as superficial spreading melanoma, which are more prone to occur at sites with acute intermittent sun damage. In summary, molecular alterations in cutaneous neoplasms of the head and neck are often related to UV exposure. Their molecular footprint often reflects the histologic tumor type, and familiarity with these changes will be increasingly necessary for diagnostic and therapeutic considerations.

Molecular cloning, characterization and expression analysis of tumor suppressor protein p53 from orange-spotted grouper, Epinephelus coioides in response to temperature stress

The tumor suppressor protein p53 is a critical component of cell cycle checkpoint responses. It upregulates the expression of cyclin-dependent kinase inhibitors in response to DNA damage and other cellular perturbations, and promotes apoptosis when DNA repair pathways are overwhelmed. In the present study, the cDNA of p53 from the orange-spotted grouper (Epinephelus coioides) (Ec-p53) was cloned by the combination of homology cloning and rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of Ec-p53 was of 1921 bp, including an open reading frame (ORF) of 1143 bp encoding a polypeptide of 380 amino acids with predicted molecular weight of 42.3 kDa and theoretical isoelectric point of 7.0. Quantitative real-time PCR (qRT-PCR) assays revealed that Ec-p53 was ubiquitously expressed in all the examined tissues but with high levels in intestine and liver of the orange-spotted grouper. In addition, we measured the DNA damage and apoptosis in the blood cells and the percentage of dead and damaged blood cells. Our results suggest that oxidative stress and DNA damage occurred in grouper in conditions where the temperature was 15 ± 0.5 °C. Furthermore, qRT-PCR and western blot confirmed that low temperature stress induced upregulation of Ec-p53 in the mRNA and protein levels. These results suggest that low temperature-induced oxidative stress may cause DNA damage or apoptosis, and cooperatively stimulate the expression of Ec-p53, which plays a critical role in immune defense and antioxidant responses.

Significance of cyclooxygenase 2, EZH-2 polycomb group and p53 expression in actinic keratosis and squamous cell carcinomas of the skin

The development and progression of squamous cell carcinoma (SCC) of the skin is characterized by an accumulation of molecular changes. The aim of this study was to investigate the association of the immunohistochemical expression of cyclooxygenase-2 (COX-2), enhancer of zeste homolog 2 (EZH-2), and p53 in actinic keratosis (AK) and SCC and detect any differences between invasive and preinvasive squamous epidermal lesions. Forty-three cases with AK, 38 with SCC, and 9 with SCC arising on AK (SCC/AK) were studied. For COX-2 immunostaining, weak or no reaction was associated with AK (58.10% of cases), whereas moderate or strong reaction with SCCs (34.2% and 39.5%, respectively). Furthermore, 88.9% of the "mixed" SCC/AK specimens demonstrated moderate reaction (χ2 = 29.924, P < 0.0001). For EZH-2 immunostaining, a weak or no reaction was observed in 62.8% of AK cases, whereas a moderate reaction was observed in 42.1% of SCCs and 77.8% of "mixed" SCC/AK cases (χ2 = 18.91, P = 0.001). Weak immunoreactivity of p53 was associated with AK (58.1%), moderate with SCC (44.7%), and strong with SCC/AK lesions (66.7%) (χ2 = 15.999, P = 0.003). COX-2, p53, but mainly EZH-2 immune expression seems to be strongly associated with the biological potential of squamous epidermal cells and seems to be differentiating SCC by comparison to AK of the skin. The value of the combined expression of these markers is worth being further investigated as an additional tool for diagnostic, prognostic, and possibly, therapeutic use.

Reduced P53 Staining in Actinic Keratosis is Associated with Squamous Cell Carcinoma: A Preliminary Study

Background:

Actinic keratosis (AK) is a cutaneous neoplasm caused by prolonged sun exposure, and may progress into squamous cell carcinoma (SCC). The p53 gene plays a central role in the development of SCC, and mutations in this gene are found in 90% of SCC and up to 100% of AK cases.

Objective:

To identify AK cases that are highly susceptible to developing SCC.

Materials and Methods:

Fifty-six AK cases were classified into two groups: AK adjacent to “normal” skin and AK adjacent to SCC. The groups were compared based on epithelial atypia, inflammation, solar elastosis, histopathological AK classification and p53 protein expression.

Results:

Of the 56 AK cases analyzed, 23% were associated with SCC. The types of AK observed were classified as follows: common, hypertrophic, atrophic, acantholytic, pigmented and bowenoid. SCC was associated with common and hypertrophic AK, and p53 staining was observed in 78% of AK cases. The mean difference in p53 immunopositivity between common AK cases associated with SCC (17%) and not associated with SCC (45.4%) was significant (p=0.011).

Conclusions:

Hypertrophic and common AK are associated with SCC, and the low percentage of p53 immunopositivity in the common type indicates a greater probability of developing into SCC.

Topical 3.0% diclofenac in 2.5% hyaluronic acid gel induces regression of cancerous transformation in actinic keratoses

BACKGROUND

Actinic keratoses (AKs) are frequently diagnosed in dermatological patients. As they represent in situ carcinomas, effective treatment is required.

OBJECTIVES

We investigated the effect of topical 3.0% diclofenac in 2.5% hyaluronic acid gel on AK.

METHODS

Sixty-five patients with AKs were clinically evaluated before and after 3 months' treatment with topical 3.0% diclofenac in 2.5% hyaluronic gel. Biopsy specimens were taken and stained with haematoxylin-eosin and immunohistological markers. Specimens were evaluated for histological type of AKs using the AK classification scheme suggested by Röwert-Huber et al. [(early) in situ squamous cell carcinoma type AK Grade I-III], number of mitoses per high-power field and expression of immunohistological markers.

RESULTS

Complete clinical resolution was observed in 11 patients (16.9%). A significant (P<0.001) downgrading of AK grade was observed. Complete histological resolution was achieved in 15 patients (23.1%). The number of mitoses per high-power field was reduced significantly (P<0.001). The expression of anti-p53-antibody decreased significantly (P=0.009), as did the expression of anti-MiB-1 antibody (P=0.021).

CONCLUSIONS

3.0% diclofenac in 2.5% hyaluronic acid gel causes regression of signs of cancerous transformation after 3 months' therapy.