Effects of long-term cryopreservation on peripheral blood progenitor cells.

BACKGROUND AIMS: The long-term stability of cryopreserved peripheral blood progenitor cells is an important issue for patients experiencing disease relapse. However, there is no consensus on how to evaluate the long-term effects of cryopreservation. We describe the effect of cryopreservation on viability and progenitor colony activity from 87 individual samples processed at the Scripps Green Hospital Stem Cell Processing Center (La Jolla, CA, USA). METHODS: We randomly selected 87 peripheral blood hematopoietic stem cell (PBHSC) samples from 60 patients and evaluated the effect of cryopreservation on sample viability and red and white cell colony activity after < 24 h and 7, 10 and 15 years of cryopreservation. Viability was assayed via trypan blue dye exclusion and activity was measured following 14 days of culture. RESULTS: An age at collection older than 50 years may result in suboptimal activity and viability following long-term cryopreservation, while gender and disease status had no effect. Cryopreservation did not significantly affect white or red cell activity following 10 years of cryopreservation. However, for samples stored longer than 10 years, viability and activity significantly decreased. We noted a positive association between higher pre-cryopreservation %CD34 count and colony activity. CONCLUSIONS: Cryopreservation of peripheral blood progenitor cells for up to 10 years results in no loss of clonogenic capacity, as determined by culture activity, although longer durations of storage may affect activity. Until validated methods are developed, cryopreserved grafts should be evaluated based on pre-freeze CD34(+) cell counts as assayed by flow cytometry, and post-thaw sample evaluation should be reserved for patients identified as poor mobilizers.

Unrecognized Value of Carcinoembryonic Antigen in Recurrent Rectal and Sigmoid Colon Cancer: Case Series.

INTRODUCTION: Carcinoembryonic antigen (CEA) surveillance is recommended in patients with colorectal cancer for detection of potentially resectable metastases. In patients with appropriate symptoms, a highly increased CEA concentration (> 5 times the upper limit of normal) is considered strongly suggestive of cancer. Despite the recognized value, the test is neither absolutely sensitive nor specific for recurrent cancer. Generally, a greater diagnostic value has been assigned to elevated CEA levels, most commonly greater than 5 ng/mL. Fluctuations within the established normal CEA range are not customarily analyzed. CASE PRESENTATIONS: We report here on 11 patients (8 women, 3 men) who, during the postoperative follow-up period, received a diagnosis of recurrent cancer despite their CEA levels exhibiting very subtle increases. Our cohort shared several similar characteristics such as a nonsmoking status, younger age (median, 52 years at initial diagnosis), and exclusive localization of the cancer to the rectosigmoid region. DISCUSSION: This important clinical observation may expand a prognostic value of CEA in a certain category of patients with colorectal cancer.

Large cell/neuroendocrine carcinoma.

Large cell neuroendocrine tumors of the lung represent a recently reclassified subtype of lung cancer with features of both small cell and non-small cell lung cancer. We review diagnostic difficulties, typical presentations, and the natural history of this tumor. We review treatment data, and suggest that as in more common types of lung cancer, multi-modality therapy may be the most promising course of treatment.