Petunia hybrida is a popular bedding plant that has a long history as a genetic model system. We report the whole-genome sequencing and assembly of inbred derivatives of its two wild parents, P. axillaris N and P. inflata S6. The assemblies include 91.3% and 90.2% coverage of their diploid genomes (1.4 Gb; 2n = 14) containing 32,928 and 36,697 protein-coding genes, respectively. The genomes reveal that the Petunia lineage has experienced at least two rounds of hexaploidization: the older gamma event, which is shared with most Eudicots, and a more recent Solanaceae event that is shared with tomato and other solanaceous species. Transcription factors involved in the shift from bee to moth pollination reside in particularly dynamic regions of the genome, which may have been key to the remarkable diversity of floral colour patterns and pollination systems. The high-quality genome sequences will enhance the value of Petunia as a model system for research on unique biological phenomena such as small RNAs, symbiosis, self-incompatibility and circadian rhythms.

Mucosal melanomas are a rare subtype of melanoma, arising in mucosal tissues, which have a very poor prognosis due to the lack of effective targeted therapies. This study aimed to better understand the molecular landscape of these cancers and find potential new therapeutic targets. Whole-exome sequencing was performed on mucosal melanomas from 19 patients and 135 sun-exposed cutaneous melanomas, with matched peripheral blood samples when available. Mutational profiles were compared between mucosal subgroups and sun-exposed cutaneous melanomas. Comparisons of molecular profiles identified 161 genes enriched in mucosal melanoma (P<0.05). KIT and NF1 were frequently comutated (32%) in the mucosal subgroup, with a significantly higher incidence than that in cutaneous melanoma (4%). Recurrent SF3B1 R625H/S/C mutations were identified and validated in 7 of 19 (37%) mucosal melanoma patients. Mutations in the spliceosome pathway were found to be enriched in mucosal melanomas when compared with cutaneous melanomas. Alternative splicing in four genes were observed in SF3B1-mutant samples compared with the wild-type samples. This study identified potential new therapeutic targets for mucosal melanoma, including comutation of NF1 and KIT, and recurrent R625 mutations in SF3B1. This is the first report of SF3B1 R625 mutations in vulvovaginal mucosal melanoma, with the largest whole-exome sequencing project of mucosal melanomas to date. The results here also indicated that the mutations in SF3B1 lead to alternative splicing in multiple genes. These findings expand our knowledge of this rare disease.

Oncogenic fusions occur in several types of cancer and can be effectively treated with ALK inhibitors; however, fusions and treatment response have not been characterized in malignant melanomas. Recently, a novel isoform of ( ) was reported in 11% of melanomas but the response of melanomas expressing to ALK inhibition has not been well characterized. We analyzed 45 melanoma patient-derived xenograft models for mRNA and protein expression. expression was identified in 11 of 45 (24.4%) melanomas. Ten melanomas express wild-type (wt) and/or and one mucosal melanoma expresses multiple novel fusion variants. Melanoma cells expressing different variants were tested for response to ALK inhibitors. Whereas the melanoma expressing were sensitive to ALK inhibitors and, the melanomas expressing wt or were not sensitive to ALK inhibitors. In addition, a patient with mucosal melanoma expressing was treated with an ALK/ROS1/TRK inhibitor (entrectinib) on a phase I trial but did not respond. Our results demonstrate fusions occur in malignant melanomas and respond to targeted therapy, whereas melanomas expressing do not respond to ALK inhibitors. Targeting fusions is an effective therapeutic option for a subset of melanoma patients, but additional clinical studies are needed to determine the efficacy of targeted therapies in melanomas expressing wt or.

Summary Genomic rearrangements resulting in activating kinase fusions have been increasingly described in a number of cancers including malignant melanoma, but their frequency in specific melanoma subtypes has not been reported. We used break-apart fluorescence in-situ hybridization (FISH) to identify genomic rearrangements in tissues from 59 patients with various types of malignant melanoma including acral lentiginous, mucosal, superficial spreading, and nodular. We identified four genomic rearrangements involving the genes BRAF, RET, and ROS1. Of these, three were confirmed by IHC or sequencing and one was found to be an ARMC10-BRAF fusion that has not been previously reported in melanoma. These fusions occurred in different subtypes of melanoma but all in tumors lacking known driver mutations. Our data suggest gene fusions are more common than previously thought-and should be further explored particularly in melanomas lacking known driver mutations.

IMPACT provides a new bioinformatics strategy to delineate candidate somatic variants and actionable therapies. This approach can be applied to other patient tumor samples to discover effective drug targets for personalized medicine.IMPACT is publicly available at http://tanlab.ucdenver.edu/IMPACT.