Further evidence of the pivotal role of CD98hc in malignant growth was provided by an embryonic stem (ES) cell transplantation model, whereby only wild type CD98hc expressing embryonic stem cells formed teratomas, while CD98hc deficient embryonic stem cells showed a significant reduction in proliferation as well as reduced cell survival characteristics, thereby leading to diminished tumor growth [7]. This evidence concerns the gene SLC3A2 and teratoma.