RAG2 and hepatocellular carcinoma: Having failed to establish any PDX from HCC biopsy in T and B cell‐deficient Rag2−/− mice, we passaged one PDX into Rag2−/− and four PDX lines into Foxn1nu (nude) mice that lack only T cells. Interestingly, one out of four Rag2−/− mice showed rising hAAT levels. Two of four PDX lines could be successfully passaged in nude mice.