Objectives: Non-Hodgkin’s lymphoma (NHL) primarily derived from the base of the tongue, is rare. Human papillomavirus (HPV) and Epstein-Barr virus (EBV) are important aetiological risk factors for tumours of the head and neck. This study describes the clinicopathological features of NHL in the tongue base and the status of HPV and EBV in these cases. Methods: Seven cases were identified from the Pathological Registry Database at Peking Union Medical College Hospital (PUMCH). The study utilized immunochemistry, in situ hybridization (ISH), and gene rearrangement to confirm the disease and and performed a clinical follow up for each case. Results: All 7 lymphomas were localized at the base of the tongue. Six of the cases exhibited tongue base masses with smooth surface membranes. One case presented as multiple deep ulcers. The most common histologic subtype was diffuse large B-cell lymphoma (DLBCL), which occurred in five cases. The other two cases were mantle cell lymphoma (MCL) and peripheral T cell lymphoma, not otherwise specified (PTCL, NOS). One of the DLBCL cases was positive for HPV DNA and diffusely expressed P16 protein. During the follow up period, the MCL patient and an elderly DLBCL patient died. The remaining five patients were alive through the end of follow up. Conclusions: Most lymphomas of the tongue base manifest as an endogenous mass without membranous change. The most common subtype of NHLs of the tongue base is DLBCL, and the occurrence at this site may have a good prognosis. With proper therapy, even late stage tongue base lymphomas can be suppressed and remain in remission.

Spikelet number per panicle is a determinative factor of rice yield. DNA repair epigenetically alters the DNA accessibility, which can eventually regulate the transcription of the target genes. However, what and how DNA repair genes are related to rice spikelet development remains unknown. Here, we report the map-based cloning of a novel spikelet number gene DES4 encoding a tetratricopeptide domain-containing protein. DES4 is a close ortholog of Arabidopsis BRU1, which is functionally related to axillary meristem development. A single base pair deletion in the last exon of DES4 caused a premature stop of the resulting protein. The des4 mutant exhibited dwarf, reduced tiller, and spikelet numbers phenotypes, as well as hypersensitivity to genotoxic stresses, suggesting its essential role in DNA repair. DES4 is predominantly expressed in young panicles and axillary meristems, and DES4 protein is localized in nucleus. A set of DNA repair genes such as cyclins, KUs (KD subunits) and recombinases were differentially regulated in des4. Meanwhile, rice spikelet number genes LAX1, LAX2, and MOC1 were significantly down-regulated in des4. In morphology, des4 showed more severe reduction of spikelet numbers than lax1, lax2, and moc1, suggesting that DES4 may work upstream of the three genes.