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Umbilical cord blood (UCB) is well known to be a rich source of hematopoietic stem cells with practical and ethical advantages. Because mesenchymal stem cells (MSCs) from bone marrow have been regarded as good materials for cell/gene therapy as well as for tissue engineering because of their multidifferentiation potential, a number of trials have been undertaken to isolate MSCs from UCB. However, the results have been controversial, and little has become known about the effect of cryopreservation on the isolation of these stem cells. In this study, we examined the ability of cryopreserved UCB-derived cells to produce MSCs. Various culture conditions, including the seeding concentrations of cells and the media used, were investigated. We were able to obtain adherent cell populations after 3 to 5 weeks in our culture conditions from UCB-derived mononuclear cell fractions that had undergone cryopreservation for 0.1 to 5 years. These cells exhibited a fibroblast-like morphology and typical mesenchymal-like immunophenotypes. The results indicate that cryopreserved human UCB fractions can be used as an alternative source of MSCs for experimental and clinical applications as well as for tissue engineering.

Histologic material from 84 cases of squamous cell carcinoma of head and neck regions was studied by double blind retrospective analysis. Sections of lymph nodes draining the tumors were examined microscopically to assess the morphologic pattern of response. Patients whose lymph nodes demonstrated active immunologic responses in the form of expanded inner cortices or increased numbers of germinal centers had 5-year survival rates significantly greater than those patients whose regional lymph nodes showed an unstimulated pattern. None of the patients whose lymph nodes showed the depleted pattern survived 5 years. These correlations were independent of the stage or grade of the tumor. Metastases occurred much more frequently in patients having regional nodes showing an unstimulated or depleted pattern than in those whose regional nodes showed evidence of immunologic activity. The data support the concept of a relationship between immunologic activity, progression of neoplasia, and survival. Morphologic assessment of immunologic activity in lymph nodes draining malignant tumors appear to be of significant value in the predicting survival.