This report describes a 30-year-old man with a testicular germ cell tumor, which later developed into acute myeloid leukemia (AML) with a common chromosomal abnormality. Testicular germ cell tumors had developed at the age of 26. He was successfully treated with surgery followed by chemotherapy.Four years after the onset of the germ cell tumor, he developed pancytopenia with elevated serum LDH. More than 95% of the bone marrow was occupied by blastic cells. These cells were CD13+, CD34+ but CD45- and MPO-. Amplification of the short arm of chromosome 12 was recognized by fluorescence in situ hybridization using the blastic cells in the bone marrow and the previous testicular tumor specimen. Because testicular germ cell tumor recurrence and other malignant tumors could be ruled out pathologically, he was diagnosed as having AML.Allogeneic stem cell transplantation from a HLA-matched sibling donor was performed after chemotherapy. As of 19 months after the transplantation, recurrence of neither AML nor testicular tumors has been observed. Because the same genetic abnormality was observed in the testicular germ cell tumor and AML in this case, the possibility of AML having a common origin with the testicular germ cell tumor is indicated.

Cerebral infarction causes permanent neurological damage. Recently, the intravenous administration of bone marrow-derived mononuclear cells has been shown to improve functional recovery through enhanced angiogenesis in an experimental stroke model. Based on these observations, we have started a phase 1/2a clinical trial of cell-based therapy for patients with cardiogenic cerebral embolism.

A 45-year-old HIV positive male who had previously been administered anti-retrovirus therapy (ART) resulting in a good virological response and with a CD4 count of more than 1,000/μl, complained of general fatigue during a periodic examination. Laboratory data showed decreased Hb (10.8 g/dl) and increased T.P (12.0 g/dl) and IgG (9,077 mg/dl). Monoclonal gammopathy (IgG-λ) was identified and bone marrow aspiration revealed 37.6% atypical plasma cells, leading to the diagnosis of symptomatic multiple myeloma (MM) (ISS clinical staging III).Four courses of VD (bortezomib+dexamethasone) therapy were administered with concurrent ART resulting in VGPR (very good partial response), followed by peripheral blood stem cell collection (the mobilizing chemotherapy was cyclophosphamide). Then, together with ART, high-dose chemotherapy (Mel-200; L-PAM) was administered with autologous peripheral blood stem cell transplantation (PBSCT). Reconstitution of white blood cells was achieved at 10 days after PBSCT. There were no adverse effects of ART and the viral load of HIV was well controlled during the period of these treatments. The final assessment was VGPR and 10 mg/day of lenalidomide has since been administered as maintenance therapy. Standard treatment combined with PBSCT for juvenile-onset MM is also effective and safe for HIV-positive patients receiving ART.

It is considered that cancer stem cells have the same characteristics as normal stem cells, such as drug-resistance, self-renewal, differentiation, and tissue-formation. Normal stem cells depend on their surroundings, a niche. Cancer stem cells may also depend on their own niche. Because cancer stem cells are resistant to present remedies, it is important to find a remedy targeting cancer stem cells. The remedy must not only target cancer stem cells themselves but also target the niche surrounding the cancer stem cells.