: Malignant Ectomesenchymoma (MEM) is a rare, aggressive soft tissue neoplasm with both neuroectodermal and mesenchymal differentiation. Congenital cases are extremely uncommon, posing significant diagnostic and therapeutic challenges. : We report a case of a full-term male neonate presenting with a large congenital neck mass and respiratory distress at birth. Imaging revealed a lobulated, heterogeneously enhancing mass in the left submandibular region with a mass effect on the airway. Open biopsy and gross resection on day six of life confirmed MEM with rhabdomyoblastic and neuroectodermal differentiation. Post-surgical staging classified the tumor as Stage I, Clinical Group II. Despite initial chemotherapy with Vincristine, Actinomycin, and Cyclophosphamide (VAC), tumor recurrence was detected at week nine of chemotherapy, necessitating a transition to Vincristine, Irinotecan, and Temozolomide (VIT). : MEM is an extremely rare neoplasm in infants, particularly in congenital presentations. Diagnosis is challenging due to its mixed histopathological features and broad differential diagnosis, including rhabdomyosarcoma, fibrosarcoma, lymphangioma, and neuroblastoma. Management typically involves multimodal therapy, with surgical resection being the mainstay of treatment. Chemotherapy is often tailored to the tumor's most aggressive component, though standardized treatment protocols remain undefined. This case highlights the importance of early recognition and a multidisciplinary approach in managing congenital MEM, as a differential diagnosis of soft tissue masses in infants, particularly in the head and neck region.

Few evidence-based trainings exist on how to equip healthcare providers, particularly nurses, with the skills to engage in cost of care conversations with patients/caregivers to mitigate the impact of cancer-related financial toxicity. This study evaluated a pilot training developed in collaboration with Triage Cancer to prepare oncology nurses to identify and assist patients/caregivers facing financial and/or legal barriers to care. Ten pediatric oncology nurses completed the training and pre/post-surveys on behaviors related to financial and legal need screening, frequency and comfort level of answering questions, knowledge, and behavior changes, along with training evaluation questions. At baseline, six nurses reported never screening for financial needs and nine for legal needs. Following the training, seven nurses stated they were likely to screen for financial/legal needs. At six months post-training, nurses had referred 85 patients/caregivers to financial/legal navigation services. Comfort levels in answering financial/legal questions increased by 6.5 points and knowledge scores increased by 1.7 points post-training. Most nurses recommended this training to other healthcare providers who work with patients with cancer and their caregivers. This study highlights the importance of providing oncology nurses with resources to engage in cost of care conversations and oncology financial legal navigation programs to mitigate the impact of cancer-related financial toxicity.

Melanin is a free-radical scavenger, antioxidant, and broadband absorber of ultraviolet (UV) radiation which protects the skin from environmental carcinogenesis. However, melanin synthesis and UV-induced reactive melanin species are also implicated in melanocyte genotoxicity. Here, we attempted to reconcile these disparate functions of melanin using a UVB-sensitive, NRAS-mutant mouse model, TpN. We crossed TpN mice heterozygous for an inactivating mutation in Tyrosinase to produce albino and black littermates on a C57BL/6J background. These animals were then exposed to a single UVB dose on postnatal day three when keratinocytes in the skin have yet to be melanized. Approximately one-third (35%) of black mice were protected from UVB-accelerated tumor formation. However, melanoma growth rates, tumor mutational burdens, and gene expression profiles were similar in melanomas from black and albino mice. Skin from albino mice contained more cyclobutane pyrimidine dimer (CPD) positive cells than black mice 1-h post-irradiation. However, this trend gradually reversed over time with CPDs becoming more prominent in black than albino melanocytes at 48 h. These results show that in the absence of epidermal pigmentation, melanocytic melanin limits the tumorigenic effects of acute UV exposure but fails to protect melanocytes from UVB-induced mutagenesis.

Skin complexion is among the most recognizable phenotypes between individuals and is mainly determined by the amount and type of melanin pigment deposited in the epidermis. Persons with dark skin complexion have more of a brown/black pigment known as eumelanin in their epidermis whereas those with fair skin complexions have less. Epidermal eumelanin acts as a natural sunblock by preventing incoming UV photons from penetrating into the skin and therefore protects against UV mutagenesis. By understanding the signaling pathways and regulation of pigmentation, strategies can be developed to manipulate skin pigmentation to improve UV resistance and to diminish skin cancer risk.

Homozygous loss of function of the melanocortin 1 receptor (MC1R) is associated with a pheomelanotic pigment phenotype and increased melanoma risk. MC1R heterozygosity is less well studied, although individuals inheriting one loss-of-function MC1R allele are also melanoma-prone. Using the K14-Scf C57BL/6J animal model whose skin is characterized by lifelong retention of interfollicular epidermal melanocytes like that of the human, we studied pigmentary, UV responses, and DNA repair capacity in the skin of variant Mc1r background. Topical application of forskolin, a skin-permeable pharmacologic activator of cAMP induction to mimic native Mc1r signaling, increased epidermal eumelanin levels, increased the capacity of Mc1r-heterozygous skin to resist UV-mediated inflammation, and enhanced the skin's ability to clear UV photolesions from DNA. Interestingly, topical cAMP induction also promoted melanin accumulation, UV resistance, and accelerated clearance in Mc1r fully intact skin. Together, our findings suggest that heterozygous Mc1r loss is associated with an intermediately melanized and DNA repair-proficient epidermal phenotype and that topical cAMP induction enhances UV resistance in Mc1r-heterozygous or Mc1r-wild-type individuals by increasing eumelanin deposition and by improving nucleotide excision repair.

Blunted melanocortin 1 receptor (MC1R) signaling promotes melanocyte genomic instability in part by attenuating cAMP-mediated DNA repair responses, particularly nucleotide excision repair (NER), which recognizes and clears mutagenic photodamage. cAMP-enhanced NER is mediated by interactions between the ataxia telangiectasia-mutated and Rad3-related (ATR) and xeroderma pigmentosum complementation group A (XPA) proteins. We now report a critical role for sirtuin 1 (SIRT1) in regulating ATR-mediated phosphorylation of XPA. SIRT1 deacetylates XPA at residues Lys-63, Lys-67, and Lys-215 to promote interactions with ATR. Mutant XPA containing acetylation mimetics at residues Lys-63, Lys-67, and Lys-215 exhibit blunted UV-dependent ATR-XPA interactions even in the presence of cAMP signals. ATR-mediated phosphorylation of XPA on Ser-196 enhances cAMP-mediated optimization of NER and is promoted by SIRT1-mediated deacetylation of XPA on Lys-63, Lys-67, and Lys-215. Interference with ATR-mediated XPA phosphorylation at Ser-196 by persistent acetylation of XPA at Lys-63, Lys-67, and Lys-215 delays repair of UV-induced DNA damage and attenuates cAMP-enhanced NER. Our study identifies a regulatory ATR-SIRT1-XPA axis in cAMP-mediated regulation melanocyte genomic stability, involving SIRT1-mediated deacetylation (Lys-63, Lys-67, and Lys-215) and ATR-dependent phosphorylation (Ser-196) post-translational modifications of the core NER factor XPA.

Using primary melanocytes and HEK293 cells, we found that cAMP signaling accelerates repair of bi- and mono-functional platinum-induced DNA damage. Elevating cAMP signaling either by the agonistic MC1R ligand melanocyte stimulating hormone (MSH) or by pharmacologic cAMP induction by forskolin enhanced clearance of intrastrand cisplatin-adducts in melanocytes or MC1R-transfected HEK293 cells. MC1R antagonists human beta-defensin 3 and agouti signaling protein blocked MSH- but not forskolin-mediated enhancement of platinum-induced DNA damage. cAMP-enhanced repair of cisplatin-induced DNA damage was dependent on PKA-mediated phosphorylation of ATR on S435 which promoted ATR's interaction with the key NER factor xeroderma pigmentosum A (XPA) and facilitated recruitment of an XPA-ATR-pS435 complex to sites of cisplatin DNA damage. Moreover, we developed an oligonucleotide retrieval immunoprecipitation (ORiP) assay using a novel platinated-DNA substrate to establish kinetics of ATR-pS435 and XPA's associations with cisplatin-damaged DNA. Expression of a non-phosphorylatable ATR-S435A construct or deletion of A kinase-anchoring protein 12 (AKAP12) impeded platinum adduct clearance and prevented cAMP-mediated enhancement of ATR and XPA's associations with cisplatin-damaged DNA, indicating that ATR phosphorylation at S435 is necessary for cAMP-enhanced repair of platinum-induced damage and protection against cisplatin-induced mutagenesis. These data implicate cAMP signaling as a critical regulator of genomic stability against platinum-induced mutagenesis.

UV radiation is a major environmental risk factor for the development of melanoma by causing DNA damage and mutations. Resistance to UV damage is largely determined by the capacity of melanocytes to respond to UV injury by repairing mutagenic photolesions. The nucleotide excision repair (NER) pathway is the major mechanism by which cells correct UV photodamage. This multistep process involves the basic steps of damage recognition, isolation, localized strand unwinding, assembly of a repair complex, excision of the damage-containing strand 3' and 5' to the photolesion, synthesis of a sequence-appropriate replacement strand, and finally ligation to restore continuity of genomic DNA. In melanocytes, the efficiency of NER is regulated by several hormonal pathways including the melanocortin and endothelin signaling pathways. Elucidating molecular mechanisms by which melanocyte DNA repair is regulated offers the possibility of developing novel melanoma-preventive strategies to reduce UV mutagenesis, especially in UV-sensitive melanoma-prone individuals.

We identified a germline TP53 c.758C > T (p.T253I) mutation in the TP53 tumor suppressor gene in a pediatric adrenocortical carcinoma (ACC) patient. Characteristic of pathogenic p53 mutations, we observed upregulation of total p53 protein levels in the patient's ACC and concurrent suppression of the wild-type (WT) TP53 allele. As ACC can be associated with Li-Fraumeni Syndrome (LFS) and the mutation has not yet been linked to LFS, we sought to characterize the functionality of the T253I mutation. We acquired p53-/- HEK293 cells and stably transduced them with GFP-tagged wild type (T253) or T253I p53 as well as two established pathogenic p53 mutants (C176Y and R213X). Compared to p53 WT, levels of T253I p53 increased while MDM2 levels decreased, suggesting a loss of MDM2-mediated regulation of T253I p53. Additionally, T253I showed a reduction in DNA damage responsive events, diminished DNA binding capabilities, and blunted transactivation capacity. These experimental data lead us to conclude that T253I represents a pathologic variant in TP53 that may predispose to LFS-associated tumors.