Characterization of circulating tumor cell aggregates identified in patients with epithelial tumors.

Circulating tumor cells (CTCs) have been implicated as a population of cells that may seed metastasis and venous thromboembolism (VTE), two major causes of mortality in cancer patients. Thus far, existing CTC detection technologies have been unable to reproducibly detect CTC aggregates in order to address what contribution CTC aggregates may make to metastasis or VTE. We report here an enrichment-free immunofluorescence detection method that can reproducibly detect and enumerate homotypic CTC aggregates in patient samples. We identified CTC aggregates in 43% of 86 patient samples. The fraction of CTC aggregation was investigated in blood draws from 24 breast, 14 non-small cell lung, 18 pancreatic, 15 prostate stage IV cancer patients and 15 normal blood donors. Both single CTCs and CTC aggregates were measured to determine whether differences exist in the physical characteristics of these two populations. Cells contained in CTC aggregates had less area and length, on average, than single CTCs. Nuclear to cytoplasmic ratios between single CTCs and CTC aggregates were similar. This detection method may assist future studies in determining which population of cells is more physically likely to contribute to metastasis and VTE.

Fluid biopsy in patients with metastatic prostate, pancreatic and breast cancers.

Hematologic spread of carcinoma results in incurable metastasis; yet, the basic characteristics and travel mechanisms of cancer cells in the bloodstream are unknown. We have established a fluid phase biopsy approach that identifies circulating tumor cells (CTCs) without using surface protein-based enrichment and presents them in sufficiently high definition (HD) to satisfy diagnostic pathology image quality requirements. This 'HD-CTC' assay finds >5 HD-CTCs mL(-1) of blood in 80% of patients with metastatic prostate cancer (n = 20), in 70% of patients with metastatic breast cancer (n = 30), in 50% of patients with metastatic pancreatic cancer (n = 18), and in 0% of normal controls (n = 15). Additionally, it finds HD-CTC clusters ranging from 2 HD-CTCs to greater than 30 HD-CTCs in the majority of these cancer patients. This initial validation of an enrichment-free assay demonstrates our ability to identify significant numbers of HD-CTCs in a majority of patients with prostate, breast and pancreatic cancers.

Beyond hairy cell: the activity of cladribine in other hematologic malignancies.

Before the contemporary development of rationally designed antineoplastic therapies, cladribine was identified as a lymphocyte-specific agent. Its profound impact on the natural history of hairy cell leukemia, with responses approaching 100% and a median duration of response of nearly a decade after only a single 7-day course, is well known and revolutionized the treatment of hairy cell leukemia. However, cladribine's impressive activity in other lymphoproliferative disorders has been generally underappreciated. Multiple single-arm phase 2 trials have demonstrated cladribine's potency across the full spectrum of lymphoid malignancies. In a limited number of phase 3 trials and cross-study analyses, cladribine compared favorably with fludarabine, another purine nucleoside analog that is more commonly used in the treatment of indolent lymphoid malignancies. Cladribine has been noted to have particular activity among lymphoid disorders with few effective therapies, specifically, chronic lymphocytic leukemia, lymphoplasmacytic lymphoma, marginal zone lymphoma, and mantle cell lymphoma. Recently approved novel agents may act in synergy with cladribine for these conditions and should be incorporated into future clinical studies.

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.