Motohiro Hashiyama

Management of undifferentiated sarcoma of the liver including living donor liver transplantation as a backup procedure

We present the cases of 3 children with huge undifferentiated sarcoma of the liver who were treated with surgical excision including liver transplantation as an option and adjuvant chemotherapy. All 3 patients were males aged 10, 13, and 15 years old. The size of the tumor was 10, 15, and 20 cm in diameter, respectively. The youngest patient is disease free and doing well 43 months after resection. The 13-year-old patient presented with tumor rupture and underwent operation. The primary tumor and the ruptured tissue fragments were removed and he was given postoperative chemotherapy. The patient is disease free and doing well 52 months after surgery. The oldest patient had an unresectable tumor in the hilar region. Preoperative chemotherapy was given but later discontinued owing to severe side effects. He underwent living donor liver transplantation followed by postoperative chemotherapy. The patient had recurrent tumor 24 months after transplantation that was excised at reoperation. He is doing well and is disease free 18 months after the second procedure. Complete removal of the tumor including total hepatectomy and transplantation when indicated and suitable pre- and/or postoperative chemotherapy is an effective treatment for children with undifferentiated sarcoma of the liver.

GREEN FLUORESCENT PROTEIN AS A SELECTABLE MARKER OF RETROVIRALLY TRANSDUCED HEMATOPOIETIC PROGENITORS

Recombinant retroviruses are most commonly used in hematopoietic stem cell gene therapy trials, but gene transfer efficiency is still inadequate with the present vectors. One approach for overcoming this problem is to develop methods of selecting and enriching the successfully transduced cells. We investigated the feasibility of using the green fluorescent protein (GFP) gene as a selectable marker of hematopoietic cells. When M1 murine leukemia cells were electroporated with GFP expression vectors, a red‐shifted mutant (S65T) GFP showed several‐fold greater fluorescence than the wild‐type GFP and generated readily detectable green light under control of SRa or CAG promoter. We then inserted an SRa‐S65T GFP cassette into the MSCV retrovirus vector and established virus producer cells. Infection of primary murine bone marrow cells resulted in a distinct population with green fluorescence, which was separated by fluorescence‐activated cell sorting. The fractionated bright cells gave rise to fluorescent spleen colonies in lethally irradiated mice, while the fluorescence‐negative cells yielded only dark colonies. These results indicated that GFP is a faithful marker in gene transfer into hematopoietic progenitor/stem cells, facilitating selection of the transduced cells and tracking of their progeny in vivo.