Clinical correlation of circulating heat shock protein 70 in acute leukemia.

The heat shock protein 70 (HSP70) is one of the molecular chaperone family involved in the protection of cells upon exposure to various types of stresses. Plasma circulating HSP70 (cHSP70) is believed to play a role in the anti-tumor immune responses and its levels may reflect the levels of severity or the disease condition. Using electrochemiluminescence protein detection immunoassay, we measured the cHSP70 levels in the plasma of patients with acute myeloid leukemia (AML) (n=96), myelodysplastic syndrome (MDS) (n=28), and acute lymphoblastic leukemia (ALL) (n=40) and compared with those in normal individuals (n=99). cHSP70 levels were significantly higher in AML (median: 10.71 ng/mL, range: 1.93-79.0 ng/mL) and ALL (median: 27.59 ng/mL, range: 5.09-129.6 ng/mL) as compared to those in MDS (median: 4.54 ng/mL, range: 1.35-58.3 ng/mL) or healthy controls (median: 4.13 ng/mL, range: 1.75-13.6 ng/mL). Levels of cHSP70 showed significant positive correlation with lactate dehydrogenase (LDH) and white blood cells (WBC) in AML and ALL patients, which may reflect overall tumor load. Furthermore, patients with higher levels of cHSP70 had significantly shorter survival in AML (P=0.04) and ALL (P=0.05), suggesting that in these two acute diseases, cHSP70 is an indicator for poor prognosis. Our data support the potential of using free cHSP70 as a biomarker in leukemias and potentially other types of cancers.

Plasma-based detection of clonality in lymphoid malignancies.

OBJECTIVES: Plasma has been found to be enriched with tumor-specific DNA, RNA, and protein in patients with hematologic disease. We assessed the utility of plasma as a DNA source for detection of genetic abnormalities in patients with suspected B- or T-cell lymphoproliferative disorders. METHODS: DNA was extracted from paired peripheral blood (PB) cells and plasma for polymerase chain reaction (PCR)-based detection of immunoglobulin heavy chain (IgH) and T-cell receptor gamma chain (TCR-gamma) rearrangements, and B-cell leukemia/lymphoma (BCL)-1/IgH and BCL-2/IgH translocations. RESULTS: Concordance between plasma and PB cell analysis was 100% for IgH (n = 57), TCR-gamma (n = 57), and BCL-1/IgH (n = 37) rearrangements, and 94% (60/64) for BCL-2/IgH; four of 11 plasma samples positive for BCL-2/IgH tested negative in paired cells. No plasma or PB cell samples from 195 healthy donors showed genetic abnormalities. CONCLUSIONS: These findings indicate that plasma is a reliable sample type for detection of abnormalities associated with B- and T-cell lymphoproliferative disorders, providing sensitivity equal to or greater than that of PB cells.

Circulating heat shock protein 70 and progression in patients with chronic myeloid leukemia.

We evaluated the association of circulating levels of heat shock protein 70 (Hsp70) in plasma with clinical behavior and progression in 139 chronic myeloid leukemia (CML) patients. Circulating Hsp70 levels did not differ significantly between CML patients in the chronic phase (n=93; median 33.24 ng/mL, range 3.89-128.2 ng/mL) and those in the accelerated/blast phase (n=46; median 26.57 ng/mL, range 4.5-114.7 ng/mL). However, overall CML patients had significantly higher levels of Hsp70 than healthy subjects (n=95, median 4.17 ng/mL, range 1.75-24.7 ng/mL) (P<0.001). In chronic phase CML patients, Hsp70 levels above the median were associated with a higher rate of progression to the accelerated/blast phase and a tendency toward shorter survival. Plasma Hsp70 thus could be a potential marker for predicting disease progression in patients with chronic phase CML.

Plasma RNA as an alternative to cells for monitoring molecular response in patients with chronic myeloid leukemia.

BACKGROUND AND OBJECTIVES: Quantitation of BCR-ABL mRNA is emerging as the standard of care to monitor the status of chronic myeloid leukemia (CML). Peripheral blood plasma was analyzed in this study because of previous detection of nucleic acids and proteins from tumor cells in plasma samples. DESIGN AND METHODS: Reverse transcriptase polyemrase chain reaction was used to establish ratios of BCR-ABL:ABL mRNA in peripheral blood cells and plasma, and absolute levels of BCR-ABL mRNA per unit volume of plasma. Samples from 160 CML patients and 180 control individuals without CML were tested. Cells and plasma samples from 93 of the CML patients were re-analyzed 3-12 months after imatinib treatment. RESULTS: Ratios of BCR-ABL:ABL mRNA in paired cell and plasma samples of the 160 CML patients correlated significantly (r=0.83; p<0.001). When results were compared directly using the sign test, the pre-therapy plasma results were significantly different from those from peripheral blood cells (p=0.028), but not bone marrow cells (p=0.119). Absolute levels of BCR-ABL mRNA in plasma strongly correlated with many laboratory characteristics in pre-therapy CML patients. Higher BCR-ABL: ABL ratios were detected in plasma samples at all time points after treatment, although this was significant only at 3 months (p=0.0003). In cases in which results from the assays disagreed, minimal residual disease was detected in plasma samples significantly more frequently than in cell samples (p<0.001). INTERPRETATION AND CONCLUSIONS: Plasma was a reliable source for monitoring BCR-ABL mRNA levels. Minimal residual disease detection from plasma was more sensitive than from cell samples. Our results suggest that absolute levels of BCR-ABL mRNA per unit volume of plasma may reflect tumor load.