Epigenetic markers in basal cell carcinoma: universal themes in oncogenesis and tumor stratification? - a short report.
ABSTRACT: BACKGROUND:Advanced basal cell carcinomas (BCCs) suffer from a scarcity of effective treatment options. Previously, we found that the targetable histone methyltransferase EZH2 was upregulated in aggressive BCC subtypes, suggesting that epigenetics may play a role in BCC progression. The purpose of this study was to determine whether EZH2-associated proteins and marks may be employed for the stratification of BCC histologic subtypes. METHODS:Sixty-two specimens (from 61 patients), representing more or less aggressive BCC histologic subtypes and matching non-malignant epidermal cells, were included in this study. Immunohistochemistry of H3K27me3, 5hmC, NSD2, MOF and JARID1B was performed to assess their putative associations with BCC histologic subtypes, as well as with EZH2 and Ki67 expression levels. RESULTS:We found that H3K27me3 and 5hmC upregulation was positively correlated with the occurrence of a less aggressive BCC histology. The modifications were also positively correlated with each other. Interestingly, we found that they were negatively correlated with the expression of EZH2, a marker for an aggressive BCC histology. The levels of NSD2, MOF, H3K27me3 and 5hmC were found to be universally upregulated in BCCs versus non-malignant epidermal cells. CONCLUSIONS:Our data reveal an EZH2-associated epigenetic marker profile that correlates with histologic signs of BCC aggressiveness. Our findings may have diagnostic and therapeutic implications, and indicate that epigenetic markers may be shared even with relatively less aggressive tumor types, thereby suggesting universal themes.
Project description:Basal cell carcinomas (BCCs) are the most common cancers in the United States. The histologic appearance distinguishes several subtypes, each of which can have a different biologic behavior. In this study, global miRNA expression was quantified by high-throughput sequencing in nodular BCCs, a subtype that is slow growing, and infiltrative BCCs, aggressive tumors that extend through the dermis and invade structures such as cutaneous nerves. Principal components analysis correctly classified seven of eight infiltrative tumors on the basis of miRNA expression. The remaining tumor, on pathology review, contained a mixture of nodular and infiltrative elements. Nodular tumors did not cluster tightly, likely reflecting broader histopathologic diversity in this class, but trended toward forming a group separate from infiltrative BCCs. Quantitative polymerase chain reaction assays were developed for six of the miRNAs that showed significant differences between the BCC subtypes, and five of these six were validated in a replication set of four infiltrative and three nodular tumors. The expression level of miR-183, a miRNA that inhibits invasion and metastasis in several types of malignancies, was consistently lower in infiltrative than nodular tumors and could be one element underlying the difference in invasiveness. These results represent the first miRNA profiling study in BCCs and demonstrate that miRNA gene expression may be involved in tumor pathogenesis and particularly in determining the aggressiveness of these malignancies.
Project description:Basal Cell Carcinoma (BCC) is one of the most diagnosed cancers worldwide. It develops due to an unrestrained Sonic Hedgehog (SHH) signaling activity in basal cells of the skin. Certain subtypes of BCC are more aggressive than others, although the molecular basis of this phenomenon remains unknown. We have previously reported that Neogenin-1 (NEO1) is a downstream target gene of the SHH/GLI pathway in neural tissue. Given that SHH participates in epidermal homeostasis, here we analyzed the epidermal expression of NEO1 in order to identify whether it plays a role in adult epidermis or BCC. We describe the mRNA and protein expression profile of NEO1 and its ligands (Netrin-1 and RGMA) in human and mouse control epidermis and in a broad range of human BCCs. We identify in human BCC a significant positive correlation in the levels of NEO1 receptor, NTN-1 and RGMA ligands with respect to GLI1, the main target gene of the canonical SHH pathway. Moreover, we show via cyclopamine inhibition of the SHH/GLI pathway of ex vivo cultures that NEO1 likely functions as a downstream target of SHH/GLI signaling in the skin. We also show how Neo1 expression decreases throughout BCC progression in the K14-Cre:Ptch1lox/lox mouse model and that aggressive subtypes of human BCC exhibit lower levels of NEO1 than non-aggressive BCC samples. Taken together, these data suggest that NEO1 is a SHH/GLI target in epidermis. We propose that NEO1 may be important in tumor onset and is then down-regulated in advanced BCC or aggressive subtypes.
Project description:Polycomb repressive complex 2 (PRC2) and its core member enhancer of zeste homolog 2 (EZH2) mediate the epigenetic gene silencing mark: trimethylation of lysine 27 on histone 3 (H3K27me3). H3K27me3 is characteristic of the chromatin at genes involved in developmental regulation in undifferentiated cells. Overexpression of EZH2 has been found in several cancer types such as breast, prostate, melanoma and bladder cancer. Moreover, overexpression is associated with highly proliferative and aggressive types of breast and prostate tumors. We have analyzed the abundance of EZH2 and H3K27me3 using immunohistochemistry in two large and well-characterized breast tumor data sets encompassing more than 400 tumors. The results have been analyzed in relation to the molecular subtypes of breast tumors (basal-like, luminal A, luminal B, HER2-enriched and normal-like), as well as in subtypes defined by clinical markers (triple negative, ER+/HER2-/Ki67low, ER+/HER2-/Ki67high and HER2+), and were validated in representative breast cancer cell lines by western blot. We found significantly different expression of both EZH2 and H3K27me3 across all subtypes with high abundance of EZH2 in basal-like, triple negative and HER2-enriched tumors, and high H3K27me3 in luminal A, HER2-enriched and normal-like tumors. Intriguingly, the two markers show an inverse correlation, particularly for the basal-like and triple negative tumors. Consequently, high expression of EZH2 was associated with poor distant disease-free survival whereas high expression of H3K27me3 was associated with better survival. Additionally, none of 182 breast tumors was found to carry a previously described EZH2 mutation affecting Tyr641. Our observation that increased expression of EZH2 does not necessarily correlate with increased abundance of H3K27me3 supports the idea that EZH2 can have effects beyond epigenetic silencing of target genes in breast cancer.
Project description:<h4>Objectives</h4>To assess compliance with 2010 National Institute for Health and Care Excellence (NICE) guidance on cancer services relating to the management of basal cell carcinomas (BCC) in the community, where except in specific circumstances it is recommended that only low-risk BCCs should be excised routinely.<h4>Design and setting</h4>A retrospective observational study of the histopathology reports of BCC excisions received from primary care in two district general hospitals in the South of England. One hundred consecutive BCC excisions were analysed from each hospital.<h4>Outcome measures</h4>The numbers of high-risk BCCs excised in primary care according to histological subtype, anatomical site and age and if these excisions were compliant with NICE 2010 guidance. Completeness of excision and mention of BCC on histology request were secondary outcomes.<h4>Results</h4>Histologically high-risk subtypes were present in 32% (64/200) of BCCs excised in the community. Only 17/64 were excised by general practitioners (GPs) who were accredited to do so. Non-compliance regarding anatomical site occurred in 16% of samples; only one was non-compliant regarding patient age. There was a high overall rate of complete excision (94.5%) with variation in presence of the term BCC on histology request forms.<h4>Conclusions</h4>NICE 2010 guidance relating to BCC excision in primary care was not followed in a considerable number of cases. Compliance with NICE 2010 guidance depends on the ability to recognise high-risk BCCs clinically and manage appropriately. It also shows that despite close supervision by secondary care, there are still failures of compliance.GP training in identification of subtypes of BCC might be improved, as well as an increase in numbers of GPs accredited to carry out high-risk BCC excisions. Difficulty in diagnosing high-risk histological subtypes of BCC preoperatively should be considered in any future revision of NICE guidance.
Project description:The tumor microenvironment (TME) may influence both cancer progression and therapeutic response. In breast cancer, particularly in the aggressive triple-negative/basal-like subgroup, patient outcome is strongly associated with the tumor's inflammatory profile. Tumor-associated macrophages (TAMs) are among the most abundant immune cells in the TME, shown to be linked to poor prognosis and therapeutic resistance. In this study, we investigated the effect of the metastasis- and inflammation-associated microenvironmental factor S100A4 on breast cancer cells (BCCs) of different subtypes and explored their further interactions with myeloid cells. We demonstrated that extracellular S100A4 activates BCCs, particularly the basal-like subtype, to elevate secretion of pro-inflammatory cytokines. The secreted factors promoted conversion of monocytes to TAM-like cells that exhibited protumorigenic activities: stimulated epithelial-mesenchymal transition, proliferation, chemoresistance, and motility in cancer cells. In conclusion, we have shown that extracellular S100A4 instigates a tumor-supportive microenvironment, involving a network of cytokines and TAM-like cells, which was particularly characteristic for basal-like BCCs and potentiated their aggressive properties. The S100A4-BCC-TAM interaction cascade could be an important contributor to the aggressive behavior of this subtype and should be further explored for therapeutic targeting.
Project description:Basal cell carcinoma (BCC) is the most common nonmelanoma skin cancer. If left untreated, BCCs can become locally aggressive or even metastasize. Currently available treatments include local destruction, surgery, and radiation. Systemic options for advanced disease are limited. The Hedgehog (Hh) pathway is aberrantly activated in a majority of BCCs and in other cancers. Hh pathway inhibitors are targeted agents that inhibit the aberrant activation of the Hh pathway, with smoothened being a targeted component. Sonidegib is a novel smoothened inhibitor that was recently approved by the US Food and Drug Administration. This review focuses on BCC pathogenesis and the clinical efficacy of sonidegib for the treatment of advanced BCC.
Project description:Basal cell carcinomas (BCCs) are the most common cancers in the US. Histologic appearance distinguishes several subtypes, each of which can have a different biologic behavior. In this study global miRNA expression was quantified by high throughput sequencing in nodular BCCs, a subtype that is slow growing, and infiltrative BCCs, aggressive tumors that extend through the dermis and invade structures such as cutaneous nerves. Principal components analysis correctly classified seven out of eight infiltrative tumors on the basis of miRNA expression. The remaining tumor, on pathology review, contained a mixture of nodular and infiltrative elements. Nodular tumors did not cluster tightly, likely reflecting broader histopathologic diversity in this class, but trended toward forming a group separate from infiltrative BCCs. qPCR assays were developed for six of the miRNAs that showed significant differences between the BCC subtypes, and five of these six were validated in a replication set of four infiltrative and three nodular tumors. The expression level of miR-183, a miRNA that inhibits invasion and metastasis in several types of malignancies, was consistently lower in infiltrative than nodular tumors and could be one element underlying the difference in invasiveness. These results represent the first miRNA profiling study in BCCs and demonstrate that miRNA gene expression may be involved in tumor pathogenesis and particularly in determining the aggressiveness of these malignancies. Total RNA was extracted from eight nodular and eight infiltrative basal cell carcinomas. miRNA was then processed into libraries using the Illumina Small RNA Ver 1.5 protocol. Samples were then sequenced on the Illumina GAII system
Project description:DNA methylation in mammals is highly dynamic during germ cell and preimplantation development but is relatively static during the development of somatic tissues. 5-hydroxymethylcytosine (5hmC), created by oxidation of 5-methylcytosine (5mC) by Tet proteins and most abundant in the brain, is thought to be an intermediary toward 5mC demethylation. We investigated patterns of 5mC and 5hmC during neurogenesis in the embryonic mouse brain. 5hmC levels increase during neuronal differentiation. In neuronal cells, 5hmC is not enriched at enhancers but associates preferentially with gene bodies of activated neuronal function-related genes. Within these genes, gain of 5hmC is often accompanied by loss of H3K27me3. Enrichment of 5hmC is not associated with substantial DNA demethylation, suggesting that 5hmC is a stable epigenetic mark. Functional perturbation of the H3K27 methyltransferase Ezh2 or of Tet2 and Tet3 leads to defects in neuronal differentiation, suggesting that formation of 5hmC and loss of H3K27me3 cooperate to promote brain development.
Project description:BACKGROUND:The histological subtype of basal-cell carcinoma (BCC) is often based on a punch biopsy; only a small part is evaluated, possibly leading to misclassification. Consensus on the optimal approach to process punch biopsies is lacking, though accurate subtyping is important for appropriate treatment. OBJECTIVE:The aim is to investigate whether evaluating 4 levels of a punch biopsy instead of 1 or 2 levels leads to more accurate subtyping of BCC. METHODS:In a retrospective study we evaluated 87 punch biopsies of histologically confirmed BCCs. The primary outcome was the proportion of "more aggressive" BCCs (nonsuperficial vs. superficial, infiltrative vs. nodular subtype) that was missed by evaluation on 1 or 2 levels, using 4-level diagnosis as reference standard. RESULTS:Eighty-five cases were available for analysis. Subtyping based on 1 level resulted in discrepancies with 4-level diagnosis in 16.5% of all cases. Underdiagnosis occurred in 14 of 58 nonsuperficial BCCs (24.1%, 95% CI: 13.9-37.2). Seven of 38 nodular BCCs (18.4%, 95% CI: 7.74-34.3) were diagnosed as superficial in 1 level, and 7 of 20 infiltrative BCCs (35%, 95% CI: 15.4-59.2) were diagnosed as superficial (n = 2) or nodular (n = 5) in 1 level. CONCLUSION:In order to maximize correct subtyping and plan appropriate treatment, we advise to evaluate at least 2, but preferably more, levels of a punch biopsy to determine the BCC subtype.
Project description:Basal cell carcinoma (BCC) is the most common human malignant neoplasm. However, there are multiple BCC subtypes that share clinical features while demanding different management. We present a case of a woman with hundreds of BCCs throughout her body that were resistant to vismodegib and without other features of basal cell nevus syndrome. Histological results of biopsies taken from various sites revealed three lesions characteristic of infundibulocystic BCCs (IBCCs) and two BCCs. Paired whole-exome sequencing performed using DNA isolated from blood and one of her IBCCs uncovered a germline heterozygous SUFU (Suppressor of Fused) mutation. The downstream location of SUFU in the hedgehog pathway explains why its mutation results in IBCCs that will not respond to any therapeutics that target upstream components of SUFU These results capture the significance of histological and genetic analysis in directing treatment.