Before a game against the Padres on August 27, 2002, Jeff met with an 11-year-old, bone cancer patient who asked Jeff to hit a home run for him.
On 28 February 2010 was announced that the 24-year old Japanese is injured with the Osteosarcoma at the knee.
More recently a study using transgenic/knockout mouse embryonic fibroblasts and human osteosarcoma cells (U2OS) has shown that FOXM1 regulates expression of a large array of G2/M-specific genes, such as Plk1, cyclin B2, Nek2 and CENPF, and plays an important role in maintenance of chromosomal segregation and genomic stability.