@article {747, title = {Mutations in KRT10 in epidermolytic acanthoma.}, journal = {J Cutan Pathol}, volume = {47}, year = {2020}, month = {2020 Jun}, pages = {524-529}, abstract = {

BACKGROUND: Epidermolytic acanthoma (EA) is a rare acquired lesion demonstrating a characteristic histopathological pattern of epidermal degeneration referred to as epidermolytic hyperkeratosis (EHK). On histopathological analysis, EA appears nearly identical to inherited EHK-associated dermatoses such as epidermolytic ichthyosis and ichthyosis bullosa of Siemens. While it has been speculated that EA is caused by mutations in KRT10, KRT1, or KRT2 found in these inherited dermatoses, none have yet been identified. Herein, we aim to identify the contributions of keratin mutations to EA.

METHODS: Using genomic DNA extracted from paraffin-embedded samples from departmental archives, we evaluated a discovery cohort using whole-exome sequencing (WES) and assessed remaining samples using Sanger sequencing screening and restriction fragment length polymorphism (RFLP) analysis.

RESULTS: DNA from 16/20 cases in our sample was of sufficient quality for polymerase chain reaction amplification. WES of genomic DNA from lesional tissue revealed KRT10 c.466C > T, p.Arg156Cys mutations in 2/3 samples submitted for examination. RFLP analysis of these samples as well as eight additional samples confirmed the mutations identified via WES and identified four additional cases with Arg156 mutations. In sum, 6/11 screened cases showed hotspot mutation in KRT10.

CONCLUSIONS: Hotspot mutations in the Arg156 position of KRT10, known to cause epidermolytic ichthyosis, also underlie EA.

}, keywords = {Acanthoma, Adult, Aged, Aged, 80 and over, Female, Genomics, Humans, Hyperkeratosis, Epidermolytic, Ichthyosis Bullosa of Siemens, Keratin-10, Keratins, Male, Middle Aged, Mutation, Skin Neoplasms, Whole Exome Sequencing}, issn = {1600-0560}, doi = {10.1111/cup.13664}, author = {Cheraghlou, Shayan and Atzmony, Lihi and Roy, Simon F and McNiff, Jennifer M and Choate, Keith A} } @article {38, title = {Cutaneous skeletal hypophosphatemia syndrome (CSHS) is a multilineage somatic mosaic RASopathy.}, journal = {J Am Acad Dermatol}, volume = {75}, year = {2016}, month = {2016 Aug}, pages = {420-7}, abstract = {

BACKGROUND: We recently demonstrated multilineage somatic mosaicism in cutaneous skeletal hypophosphatemia syndrome (CSHS), which features epidermal or melanocytic nevi, elevated fibroblast growth factor (FGF)-23, and hypophosphatemia, finding identical RAS mutations in affected skin and bone.

OBJECTIVE: We sought to: (1) provide an updated overview of CSHS; (2) review its pathobiology; (3)~present a new patient with CSHS; and (4) discuss treatment modalities.

METHODS: We searched PubMed for "nevus AND rickets," and "nevus AND hypophosphatemia," identifying cases of nevi with hypophosphatemic rickets or elevated serum FGF-23. For our additional patient with CSHS, we performed histopathologic and radiographic surveys of skin and skeletal lesions, respectively. Sequencing was performed for HRAS, KRAS, and NRAS to determine causative mutations.

RESULTS: Our new case harbored somatic activating HRAS p.G13~R mutation in affected tissue, consistent with previous findings. Although the mechanism of FGF-23 dysregulation is unknown in CSHS, interaction between FGF and MAPK pathways may provide insight into pathobiology. Anti-FGF-23 antibody KRN-23 may be useful in managing CSHS.

LIMITATIONS: Multilineage RAS mutation in CSHS was recently identified; further studies on mechanism are unavailable.

CONCLUSION: Patients with nevi in association with skeletal disease should be evaluated for serum phosphate and FGF-23. Further studies investigating the role of RAS in FGF-23 regulation are needed.

}, keywords = {Antibodies, Monoclonal, Antibodies, Monoclonal, Humanized, Fibroblast Growth Factor-23, Fibroblast Growth Factors, Genes, ras, Humans, Mosaicism, Nevus, Pigmented, Osteomalacia, Rickets, Hypophosphatemic, Skin Neoplasms, Syndrome}, issn = {1097-6787}, doi = {10.1016/j.jaad.2015.11.012}, author = {Lim, Young H and Ovejero, Diana and Derrick, Kristina M and Collins, Michael T and Choate, Keith A} } @article {639, title = {Keratoacanthoma Shares Driver Mutations with Cutaneous Squamous Cell Carcinoma.}, journal = {J Invest Dermatol}, volume = {136}, year = {2016}, month = {2016 08}, pages = {1737-1741}, keywords = {Aged, Aged, 80 and over, Biomarkers, Tumor, Biopsy, Carcinoma, Squamous Cell, Cohort Studies, Diagnosis, Differential, Exome, Female, Humans, Keratoacanthoma, Loss of Heterozygosity, Male, Middle Aged, Mutation, Polymorphism, Single Nucleotide, Skin, Skin Neoplasms, Whole Exome Sequencing}, issn = {1523-1747}, doi = {10.1016/j.jid.2016.04.002}, author = {Lim, Young H and Fisher, Jonathan M and Bosenberg, Marcus W and Choate, Keith A and Ko, Christine J} } @article {61, title = {Somatic Mutations in NEK9 Cause Nevus Comedonicus.}, journal = {Am J Hum Genet}, volume = {98}, year = {2016}, month = {2016 May 05}, pages = {1030-1037}, abstract = {

Acne vulgaris (AV) affects most adolescents, and of those affected, moderate to severe disease occurs in 20\%. Comedones, follicular plugs consisting of desquamated keratinocytes and sebum, are central to its pathogenesis. Despite high heritability in first-degree relatives, AV genetic determinants remain incompletely understood. We therefore employed whole-exome sequencing (WES) in nevus comedonicus (NC), a rare disorder that features comedones and inflammatory acne cysts in localized, linear configurations. WES identified somatic NEK9 mutations, each affecting highly conserved residues within its kinase or RCC1 domains, in affected tissue of three out of three NC-affected subjects. All mutations are gain of function, resulting in increased phosphorylation at Thr210, a hallmark of NEK9 kinase activation. We found that comedo formation in NC is marked by loss of follicular differentiation markers, expansion of keratin-15-positive cells from localization within the bulge to the entire sub-bulge follicle and cyst, and ectopic expression of keratin 10, a marker of interfollicular differentiation not present in normal follicles. These findings suggest that NEK9 mutations in NC disrupt normal follicular differentiation and identify NEK9 as a potential regulator of follicular homeostasis.

}, keywords = {Adolescent, Adult, Child, Female, Fluorescent Antibody Technique, High-Throughput Nucleotide Sequencing, Humans, Male, Mutation, Nevus, NIMA-Related Kinases, Prognosis, Skin Neoplasms, Young Adult}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.03.019}, author = {Levinsohn, Jonathan L and Sugarman, Jeffrey L and McNiff, Jennifer M and Antaya, Richard J and Choate, Keith A} } @article {125, title = {Somatic p.T771R KDR (VEGFR2) Mutation Arising in a Sporadic Angioma During Ramucirumab Therapy.}, journal = {JAMA Dermatol}, volume = {151}, year = {2015}, month = {2015 Nov}, pages = {1240-3}, abstract = {

IMPORTANCE: Inhibition of angiogenesis is an effective anticancer strategy because neoplasms require a rich blood supply. Ramucirumab, approved by the US Food and Drug Administration in 2014 to treat gastric adenocarcinomas and non-small cell lung carcinomas, targets vascular endothelial growth factor 2 (VEGFR2). We identified a patient prescribed a regimen of irinotecan hydrochloride, cetuximab, and ramucirumab for metastatic rectal cancer (diagnosed in November 2013 and treated through early January 2015) who developed a new-onset, expanding vascular lesion on his right leg. Via exome sequencing, we found that the lesion contained a single somatic mutation in KDR (encodes VEGFR2), possibly in response to ramucirumab. Vascular tumors are not a known complication of antiangiogenic therapeutics.

OBSERVATIONS: Exome sequencing of the well-demarcated, blanching vascular lesion on the lateral right shin revealed a somatic p.T771R mutation in KDR, without evidence of other somatic mutations or loss of heterozygosity. Histological features included lobules of small vessels within the dermis, resembling a tufted angioma.

CONCLUSIONS AND RELEVANCE: A potential adverse effect of ramucirumab in combination therapy is the development of sporadic angiomas. The p.T771R mutation was previously implicated in autophosphorylation of VEGFR2 and reported in angiosarcomas alongside other driver mutations. Our observations suggest that this mutation confers a proliferative advantage in the setting of ramucirumab therapy. Patients receiving ramucirumab should be monitored for the development of new vascular lesions.

}, keywords = {Adult, Angiogenesis Inhibitors, Antibodies, Monoclonal, Antineoplastic Combined Chemotherapy Protocols, Camptothecin, Cetuximab, Hemangioma, Humans, Irinotecan, Male, Mutation, Rectal Neoplasms, Skin Neoplasms, Vascular Endothelial Growth Factor Receptor-2}, issn = {2168-6084}, doi = {10.1001/jamadermatol.2015.1925}, author = {Lim, Young H and Odell, Ian D and Ko, Christine J and Choate, Keith A} } @article {289, title = {Multilineage somatic activating mutations in HRAS and NRAS cause mosaic cutaneous and skeletal lesions, elevated FGF23 and hypophosphatemia.}, journal = {Hum Mol Genet}, volume = {23}, year = {2014}, month = {2014 Jan 15}, pages = {397-407}, abstract = {

Pathologically elevated serum levels of fibroblast growth factor-23 (FGF23), a bone-derived hormone that regulates phosphorus homeostasis, result in renal phosphate wasting and lead to rickets or osteomalacia. Rarely, elevated serum FGF23 levels are found in association with mosaic cutaneous disorders that affect large proportions of the skin and appear in patterns corresponding to the migration of ectodermal progenitors. The cause and source of elevated serum FGF23 is unknown. In those conditions, such as epidermal and large congenital melanocytic nevi, skin lesions are variably associated with other abnormalities in the eye, brain and vasculature. The wide distribution of involved tissues and the appearance of multiple segmental skin and bone lesions suggest that these conditions result from early embryonic somatic mutations. We report five such cases with elevated serum FGF23 and bone lesions, four with large epidermal nevi and one with a giant congenital melanocytic nevus. Exome sequencing of blood and affected skin tissue identified somatic activating mutations of HRAS or NRAS in each case without recurrent secondary mutation, and we further found that the same mutation is present in dysplastic bone. Our finding of somatic activating RAS mutation in bone, the endogenous source of FGF23, provides the first evidence that elevated serum FGF23 levels, hypophosphatemia and osteomalacia are associated with pathologic Ras activation and may provide insight in the heretofore limited understanding of the regulation of FGF23.

}, keywords = {Adolescent, Child, Exome, Female, Fibroblast Growth Factors, Gene Expression Regulation, Developmental, GTP Phosphohydrolases, Humans, Hypophosphatemia, Male, Membrane Proteins, Mutation, Nevus, Nevus, Pigmented, Osteomalacia, Proto-Oncogene Proteins p21(ras), Sequence Analysis, DNA, Skin, Skin Neoplasms}, issn = {1460-2083}, doi = {10.1093/hmg/ddt429}, author = {Lim, Young H and Ovejero, Diana and Sugarman, Jeffrey S and Deklotz, Cynthia M C and Maruri, Ann and Eichenfield, Lawrence F and Kelley, Patrick K and J{\"u}ppner, Harald and Gottschalk, Michael and Tifft, Cynthia J and Gafni, Rachel I and Boyce, Alison M and Cowen, Edward W and Bhattacharyya, Nisan and Guthrie, Lori C and Gahl, William A and Golas, Gretchen and Loring, Erin C and Overton, John D and Mane, Shrikant M and Lifton, Richard P and Levy, Moise L and Collins, Michael T and Choate, Keith A} }