Whole genome sequencing of HER2-positive metastatic extramammary Paget's disease: a case report.

BACKGROUND: Extramammary Paget's disease (EMPD) is a rare cancer that occurs within the epithelium of the skin, arising predominantly in areas with high apocrine gland concentration such as the vulva, scrotum, penis and perianal regions. Here, we aim to integrate clinicopathological data with genomic analysis of aggressive, rapidly-progressing de novo metastatic EMPD responding to HER2-directed treatment in combination with other agents, to attain a more comprehensive understanding of the disease landscape. METHODS: Immunohistochemical staining on the scrotal wall tumor and bone marrow metastasis demonstrated HER2 overexpression. Whole genome sequencing of the tumor and matched blood was performed. RESULTS: Notable copy number gains (log2FC > 0.9) on chromosomes 7 and 8 were detected (n = 81), with 92.6% of these unique genes specifically located on chromosome 8. Prominent cancer-associated genes include ZNF703, HOOK3, DDHD2, LSM1, NSD3, ADAM9, BRF2, KAT6A and FGFR1. Interestingly, ERBB2 gene did not exhibit high copy number gain (log2FC = 0.4) although 90% of tumor cells stained HER2-positive. Enrichment in pathways associated with transforming growth factor-beta (TGFß) (FDR = 0.0376, Enrichment Ratio = 8.12) and fibroblast growth factor receptor (FGFR1) signaling (FDR = 0.0082, Enrichment Ratio = 2.3) was detected. Amplicon structure analysis revealed that this was a simple-linear amplification event. CONCLUSION: Whole genome sequencing revealed the underlying copy number variation landscape in HER2-positive metastatic EMPD. The presence of alternative signalling pathways and genetic variants suggests potential interactions with HER2 signalling, which possibly contributed to the HER2 overexpression and observed response to HER2-directed therapy combined with other agents in a comprehensive treatment regimen.

FOXM1: a new therapeutic target of extramammary Paget disease.

Extramammary Paget disease (EMPD) is a rare skin cancer that primarily affects older individuals predominantly in areas with apocrine sweat glands. Although most early EMPD lesions are indolent, patients with metastatic EMPD have a poor prognosis due to the lack of effective systemic treatment. In this study, we investigated the role of forkhead box M1 (FOXM1), a potent transcription factor, in EMPD and assessed the potential of FOXM1 as a therapeutic target. Immunohistochemistry of 112 primary and 17 metastatic EMPD samples revealed that FOXM1 expression increased with tumor progression. Patients in whom FOXM1 was expressed in more than 10% of tumor cells had significantly shorter disease-specific survival than the other patients (p = 0.0397). In in vitro studies using our newly established EMPD cell line, KS-EMPD-1, we found high expression of FOXM1. Knockdown of FOXM1 impaired tumor cell viability, migration, and invasion. Inhibition of FOXM1 using thiostrepton also reduced tumor cell viability in a dose-dependent manner. These findings suggest that FOXM1 is a promising therapeutic target for patients with EMPD.

Whole genome methylation sequencing reveals epigenetic landscape and abnormal expression of FABP5 in extramammary Paget's disease.

BACKGROUND: Extramammary Paget's disease (EMPD) is a rare cutaneous malignant tumor with a high recurrence rate after surgery. However, the genetic and epigenetic alterations underlying its pathogenesis remain unknown. DNA methylation is an important epigenetic modification involved in many biological processes. METHODS: In this study, enzymatic methyl-sequencing (EM-seq) technique was used to investigate the landscape of genome-wide DNA methylation from three pairs of tumor tissues and adjacent tissues of patients with EMPD. Additionally, we conducted histopathological examinations to assess the expression of fatty acid-binding protein 5 (FABP5) in another three paired samples from EMPD patients. RESULTS: The cluster analysis showed the good quality of the samples. A differential methylation region (DMR) heat map was used to quantitatively characterize genome-wide methylation differences between tumors and controls. Global DNA methylation level is lower in EMPD tissue compared to matched controls, indicating that DNA methylation discriminates between tumor and normal skin. And the top hypomethylation gene on the promoter region in tumor tissues was FABP5 on chromosome 8 with 38.44% decreased median methylation. We next identified the expression of FABP5 in paired tumors and adjacent tissues in three additional patients with EMPD. Immunofluorescence results showed FABP5 highly expressed in tumor tissues and co-located with CK7, CK20 and EMA. GO and KEGG enrichment analysis showed DMR genes on promoter are mainly enriched in the calcium ion transport, GTPase mediated signal transduction, Rap1 signaling pathway and GnRH signaling pathway. CONCLUSION: Taken together, our findings provide the first description of the whole genome methylation map of EMPD and identify FABP5 as a pathogenic target of EMPD.

Overexpression of heat shock protein 90 through the downregulation of miR-9-5p in extramammary Paget's disease.

Heat shock protein 90 (HSP90) facilitates diverse cellular processes by interacting process with more than 200 client proteins. Overexpression of HSP90 contributes to the pathogenesis of various malignant tumors, and HSP90 inhibitors attenuate the progression of malignant tumors in vitro/vivo. Numerous clinical trials have used HSP90 inhibitors to treat several cancers, and pimitespib (an HSP90 inhibitor) is covered by insurance for advanced gastrointestinal stromal tumor in Japan. In this study, we investigated the expression pattern of HSP90 and analyzed its clinical significance in extramammary Paget's disease (EMPD). All 77 EMPD tissues investigated were positive for HSP90 expression. The immunoreactivity of HSP90 in fetal cases due to EMPD tended to be highly stained. Although there was no significant difference in HSP90 mRNA levels between 24 paired lesional and nonlesional tissues, microRNA-inhibiting HSP90 levels in tumor tissues were significantly decreased compared with those in normal tissues. Thus, HSP90 may play an important role in the pathogenesis of EMPD and may be a novel therapeutic target for EMPD.

Intertumor and intratumor heterogeneity of PIK3CA mutations in extramammary Paget's disease.

Although the prognosis of patients with extramammary Paget's disease (EMPD) treated with radical resection is good, the prognosis of EMPD with distant metastasis is very poor. PIK3CA mutations predict a good response to PIK3CA inhibitors. The aim of this study was to investigate the occurrence rate of PIK3CA mutations (including multiple mutations [MM]) related to the intertumor and intratumor heterogeneity in EMPD and to evaluate the correlation between these mutations and clinical parameters of EMPD. We performed droplet digital polymerase chain reaction to detect PIK3CA mutations (E542K, E545K, H1047R, and MM) in 68 patients with EMPD. In addition, we investigated the presence of PIK3CA mutations at multiple sites in 16 patients with PIK3CA mutations to assess the intratumor heterogeneity of PIK3CA mutations in EMPD. The frequency of one or more PIK3CA mutations in patients with EMPD was 30.8% (21/68). The frequency of E542K, E545K, H1047R, and MM were 10.2% (7/68), 13.2% (9/68), 11.7% (8/68), and 4.4% (3/68), respectively. No significant correlation was found between PIK3CA mutation patterns and clinical parameters. Of the 21 patients with PIK3CA mutations, 16 with tissue samples that could be analyzed at multiple sites were examined. The proportion of patients with the same PIK3CA mutations at all sites was 12.5% (2/16). The proportion of patients with the same PIK3CA mutations at least two or more sites, but not at all sites, was 31.2% (5/16). The proportion of patients with no PIK3CA mutations at other sites was 37.5% (6/16). The proportion of patients with other PIK3CA mutations at other sites was 18.7% (3/16). There is intertumor and intratumor heterogeneity of PIK3CA mutations. PIK3CA mutations in EMPD may be progressor mutations in EMPD.

Genomic landscape of circulating tumour DNA in metastatic extramammary Paget's disease.

Although cancer personalized profiling by deep sequencing (CAPP-Seq) of cell-free DNA (cfDNA) has gained attention, the clinical utility of circulating tumour DNA (ctDNA) in extramammary Paget's disease (EMPD) has not been investigated. In this study, genomic alterations in the cfDNA and tumour tissue DNA were investigated in seven patients with metastatic EMPD. CAPP-Seq revealed mutations in 18 genes, 11 of which have not yet been reported in EMPD. The variant allele frequency of some of the mutated genes reflected the disease course in patients with EMPD. In one patient, the mutation was detected even though imaging findings revealed no metastasis. In another patient with triple EMPD (genital area and both axilla), cfDNA sequencing detected the mutation in a rib metastatic lesion, which was also detected in both axilla lesions but not the genital region. Investigations of the ctDNA may be useful towards the elucidation of clonal evolution in EMPD.

Transcriptome sequencing reveals a lncRNA-mRNA interaction network in extramammary Paget's disease.

BACKGROUND: Extramammary Paget's disease (EMPD) is a rare malignant intraepidermal adenocarcinoma that is poorly understood. Regulatory long noncoding RNAs (lncRNAs) are characterized in many species and shown to be involved in processes such as development and pathologies, revealing a new layer of regulation in different diseases, especially in cancer studies. In the present study, we used high-throughput sequencing to reveal the lncRNA-mRNA interaction network in extramammary Paget's disease. METHODS: High-throughput sequencing was used to identify differentially expressed lncRNA and mRNA profiles between EMPD patients and healthy controls. Then, a series of bioinformatics analyses were conducted to construct the lncRNA-mRNA interaction network, which was finally confirmed in vitro. RESULTS: Six pairs of EMPD tumor and normal skin samples were collected and sequenced to identify the differentially expressed lncRNA and mRNA profiles between EMPD and healthy controls. A total of 997 differentially expressed mRNAs and 785 differentially expressed lncRNAs were identified. The GO and KEGG analyses show that epidermal development and cell adhesion play important roles in EMPD. The results of the lncRNA-mRNA interaction network analysis suggested that NEAT1, PGAP1, FKBP5 and CDON were the pivotal nodes of the network and that lncRNA NEAT1 might regulate mRNA PGAP1, FKBP5 and CDON. The results of the quantitative real-time RT-PCR performed in ten other patients for NEAT1, PGAP1, FKBP5 and CDON were consistent with those of the sequencing analysis. Moreover, an in vitro experiment confirmed the interactions between NEAT1 and PGAP1, FKBP5 and CDON in human immortalized keratinocytes. CONCLUSION: These findings suggest that the lncRNA-mRNA interaction network based on four pivotal nodes, NEAT1, PGAP1 FKBP5 and CDON, may play an important role in EMPD, which will contribute to a deeper understanding of the pathogenesis of EMPD.

Trop2 Expression in Extramammary Paget's Disease and Normal Skin.

Extramammary Paget's disease (EMPD) is a rare skin cancer arising in the apocrine gland-rich areas. Most EMPD tumors are dormant, but metastatic lesions are associated with poor outcomes owing to the lack of effective systemic therapies. Trophoblast cell surface antigen 2 (Trop2), a surface glycoprotein, has drawn attention as a potential therapeutic target for solid tumors. Sacituzumab govitecan, an antibody-drug conjugate of Trop2, has recently entered clinical use for the treatment of various solid cancers. However, little is known about the role of Trop2 in EMPD. In this study, we immunohistochemically examined Trop2 expression in 116 EMPD tissue samples and 10 normal skin tissues. In normal skin, Trop2 was expressed in the epidermal keratinocytes, inner root sheaths, and infundibulum/isthmus epithelium of hair follicles, eccrine/apocrine glands, and sebaceous glands. Most EMPD tissues exhibited homogeneous and strong Trop2 expression, and high Trop2 expression was significantly associated with worse disease-free survival (p = 0.0343). These results suggest the potential use of Trop2-targeted therapy for EMPD and improve our understanding of the skin-related adverse effects of current Trop2-targeted therapies such as sacituzumab govitecan.

Integrative bioinformatics approaches to map key biological markers and therapeutic drugs in Extramammary Paget's disease of the scrotum.

Extramammary Paget's disease (EMPD) is an intra-epidermal adenocarcinoma. Till now, the mechanisms underlying the pathogenesis of scrotal EMPD is poorly known. This present study aims to explore the knowledge of molecular mechanism of scrotal EMPD by identifying the hub genes and candidate drugs using integrated bioinformatics approaches. Firstly, the microarray datasets (GSE117285) were downloaded from the GEO database and then analyzed using GEO2R in order to obtain differentially expressed genes (DEGs). Moreover, hub genes were identified on the basis of their degree of connectivity using Cytohubba plugin of cytoscape tool. Finally, GEPIA and DGIdb were used for the survival analysis and selection of therapeutic candidates, respectively. A total of 786 DEGs were identified, of which 10 genes were considered as hub genes on the basis of the highest degree of connectivity. After the survival analysis of ten hub genes, a total of 5 genes were found to be altered in EMPD patients. Furthermore, 14 drugs of CHEK1, CCNA2, and CDK1 were found to have therapeutic potential against EMPD. This study updates the information and yields a new perspective in the context of understanding the pathogenesis of EMPD. In future, hub genes and candidate drugs might be capable of improving the personalized detection and therapies for EMPD.

Programmed Death-Ligand 1 and Programmed Death-Ligand 2 Expression Can Affect Prognosis in Extramammary Paget's Disease.

BACKGROUND: Extramammary Paget's disease (EMPD) is a type of carcinoma that usually progresses slowly but may cause metastasis and subsequent death of patients. We investigated the relationship between the expression of programmed death-ligand 1 (PD-L1)/programmed death-ligand 2 (PD-L2) and stromal CD8+ tumor-infiltrating lymphocytes (TILs) in EMPD and clinicopathological findings, including prognosis. MATERIALS AND METHODS: We examined 47 cases of EMPD and performed immunohistochemical staining of formalin-fixed paraffin-embedded full-face sections. RESULTS: PD-L1 expression in tumor cells was observed in 13 cases (27.7%) while PD-L2 expression was observed in 21 cases (44.7%). The cumulative postoperative recurrence-free rate in the group with positivity for PD-L1 and/or PD-L2 with a low CD8+ TIL count was significantly lower than that of the corresponding group with a high CD8+ TIL count and of the PD-L1- and PD-L2-negative group (p=0.026). CONCLUSION: The expression of PD-L1/PD-L2 in tumor cells was shown to be a factor for poor prognosis.

Unbiased Detection of Driver Mutations in Extramammary Paget Disease.

PURPOSE: Extramammary Paget disease (EMPD) is an uncommon skin malignancy whose genetic alterations are poorly characterized. Previous reports identified mutations in chromatin remodeling genes and PIK3CA. In order to unambiguously determine driver mutations in EMPD, we analyzed 87 EMPD samples using exome sequencing in combination with targeted sequencing. EXPERIMENTAL DESIGN: First, we analyzed 37 EMPD samples that were surgically resected using whole-exome sequencing. Based on several in silico analysis, we built a custom capture panel of putative driver genes and analyzed 50 additional formalin-fixed, paraffin-embedded samples using target sequencing. ERBB2 expression was evaluated by HER2 immunohisotochemistry. Select samples were further analyzed by fluorescence in situ hybridization. RESULTS: A median of 92 mutations/sample was identified in exome analysis. A union of driver detection algorithms identified ERBB2, ERBB3, KMT2C, TP53, PIK3CA, NUP93, AFDN, and CUX1 as likely driver mutations. Copy-number alteration analysis showed regions spanning CDKN2A as recurrently deleted, and ERBB2 as recurrently amplified. ERBB2, ERBB3, and FGFR1 amplification/mutation showed tendency toward mutual exclusivity. Copy-number alteration load was associated with likelihood to recur. Mutational signatures were dominated by aging and APOBEC activation and lacked evidence of ultraviolet radiation. HER2 IHC/fluorescence in situ analysis validated ERBB2 amplification but was underpowered to detect mutations. Tumor heterogeneity in terms of ERBB2 amplification status was observed in some cases. CONCLUSIONS: Our comprehensive, unbiased analysis shows EMPD is characterized by alterations involving the PI3K-AKT pathway. EMPD is distinct from other skin cancers in both molecular pathways altered and etiology behind mutagenesis.

Extramammary Paget's disease patient-derived xenografts harboring ERBB2 S310F mutation show sensitivity to HER2-targeted therapies.

Although the prognosis of advanced extramammary Paget's disease (EMPD) is poor, there have been no preclinical research models for the development of novel therapeutics. This study aims to establish a preclinical research model for EMPD. We transplanted EMPD tissue into immunodeficient NOD/Scid mice. Histopathological and genetic analyses using a comprehensive cancer panel were performed. For in vivo preclinical treatments, trastuzumab, lapatinib, docetaxel, or eribulin were administered to patient-derived xenograft (PDX) models. Tissue transplanted from the EMPD patient was enlarged in NOD/Scid mice and was transplanted into further generations. Both the transplantation of PDX into nu/nu mice and the reanimation of the cryopreserved xenografted tumors in NOD/Scid mice were successful. We also established an EMPD-PDX-derived primary cell culture. Histopathologically, the xenografted tumors were positive for CK7, which was consistent with the patient's tumors. Genetically, the pathogenic mutation ERBB2 S310F was detected in the patient's tumors (primary intraepidermal lesion, metastatic lymph node) and was observed in the xenografted tumors even after continued passages. The xenografted tumors responded well to trastuzumab and lapatinib therapy. Also, cytotoxic agents (docetaxel and eribulin) were effective against the xenografted tumors. This PDX model (EMPD-PDX-H1) could be a powerful tool for the research and development of EMPD treatments.

Comparison of the biomarkers for targeted therapies in primary extra-mammary and mammary Paget's disease.

BACKGROUND: Primary Extra-mammary Paget's disease (EMPD) is a very rare cutaneous adenocarcinoma affecting anogenital or axillary regions. It is characterized by a prolonged course with recurrences and eventually distant metastatic spread for which no specific therapy is known. METHODS: Eighteen EMPD (13 vulvar and five scrotal) and ten mammary Paget's disease (MPD) cases were comprehensively profiled for gene mutations, fusions and copy number alterations, and for therapy-relevant protein biomarkers). RESULTS: Mutations in TP53 and PIK3CA were the most frequent in both cohorts: 7/15 and 5/15 in EMPD; 1/6 and 4/7 in MPD HER2 gene amplification was detected in 4/18 EMPD (3 vulvar and 1 scrotal case) in contrast to MPD where it was detected in the majority (7/8) of cases. TOP2A gene amplification was seen in 2/12 EMPD and 1/6 MPD, respectively. Similarly, no difference in estrogen receptor expression was seen between the EMPD (4/15) and MPD (3/10). Androgen receptor was also expressed in the majority of both cohorts (12/16 EMPD) and (7/8 MPD).Here ARv7 splice variant was detected in 1/7 EMPD and 1/4 MPD cases, respectively. PD-L1 expression on immune cells was exclusively observed in three vulvar EMPD. In contrast to MPD, six EMPDs harbored a "high" tumor mutation burden (≥10 mutations/Mb). All tested cases from both cohorts were MSI stable. CONCLUSIONS: EMPD shares some targetable biomarkers with its mammary counterpart (steroid receptors, PIK3CA signaling pathways, TOP2A amplification). HER2 positivity is notably lower in EMPD while biomarkers to immune checkpoint inhibitors (high TMB and PD-L1) were observed in some EMPD. Given that no consistent molecular alteration characterizes EMPD, comprehensive theranostic profiling is required to identify individual patients with targetable molecular alterations.