ABSTRACT
Head and neck tumors often have complex anatomical structures and are adjacent to important organs. Radiation injury caused by conventional radiotherapy technology is the main dose-limiting factor. Carbon ion beam has become the most ideal radiation to replace photon due to its excellent relative biological effect and Bragg peak. By 2019, 32 000 people worldwide have received carbon ion radiotherapy (CIRT). Despite the efficient tumor killing ability of this technology, radiation injury cannot be avoided. This article reviews the types and incidence of moderate to severe radiation injury caused by CIRT in head and neck cancer to provide a comprehensive understanding of the potential risks in CIRT.
ABSTRACT
Lycophytes and seed plants constitute the typical vascular plants. Lycophytes have been thought to have no paleo-polyploidization although the event is known to be critical for the fast expansion of seed plants. Here, genomic analyses including the homologous gene dot plot analysis detected multiple paleo-polyploidization events, with one occurring approximately 13-15 million years ago (MYA) and another about 125-142 MYA, during the evolution of the genome of Selaginella moellendorffii, a model lycophyte. In addition, comparative analysis of reconstructed ancestral genomes of lycophytes and angiosperms suggested that lycophytes were affected by more paleo-polyploidization events than seed plants. Results from the present genomic analyses indicate that paleo-polyploidization has contributed to the successful establishment of both lineages-lycophytes and seed plants-of vascular plants.