Estimation of the relationship between caspase-3 expression and clinical outcome of Burkitt's and Burkitt-like lymphoma

Procaspase-3 Overexpression in Cancer: A Paradoxical Observation with Therapeutic Potential

Many anticancer strategies rely on the promotion of apoptosis in cancer cells as a means to shrink tumors. Crucial for apoptotic function are executioner caspases, most notably caspase-3, that proteolyze a variety of proteins, inducing cell death. Paradoxically, overexpression of procaspase-3 (PC-3), the low-activity zymogen precursor to caspase-3, has been reported in a variety of cancer types. Until recently, this counterintuitive overexpression of a pro-apoptotic protein in cancer has been puzzling. Recent studies suggest subapoptotic caspase-3 activity may promote oncogenic transformation, a possible explanation for the enigmatic overexpression of PC-3. Herein, the overexpression of PC-3 in cancer and its mechanistic basis is reviewed; collectively, the data suggest the potential for exploitation of PC-3 overexpression with PC-3 activators as a targeted anticancer strategy.

Activated Caspase 3 Expression in Remnant Disease After Neoadjuvant Chemotherapy May Predict Outcomes of Breast Cancer Patients

BACKGROUND

A number of studies have indicated that patients obtaining a pathological complete response (pCR) from neoadjuvant chemotherapy (NAC) have a good prognosis; however, prognostic factors for non-pCR patients are not yet well-established. By examining remnant cancer in non-pCR patients, the expression of cleaved Caspase 3 (Casp3), an activated apoptotic marker, was immunohistochemically investigated to determine whether this protein has the potential to serve as a novel marker for predicting patient outcomes.

METHODS

We investigated 218 patients with invasive breast cancer who received NAC and underwent surgery during the 2006 through 2008 period at our institution. Following surgery, standard adjuvant endocrine therapy was administered if a tumor was hormone receptor-positive. Casp3 was evaluated in remnant cancer based on the number of positive cells in five high-power fields.

RESULTS

pCR was obtained in 49 patients, and 50 of the 169 non-pCR patients developed recurrences during the median 82-month observation period. We found large tumor size, lymph node involvement, lymph vessel invasion, estrogen receptor-negative, progesterone receptor-negative, high Ki67 and high Casp3 expression to be factors related to tumor recurrence. A logistic regression model revealed that lymph node involvement, as well as high Ki67 and Casp3, to be factors independently predicting recurrence, while lymph vessel invasion and high Ki67 expression were found to be related to breast cancer mortality.

CONCLUSIONS

Patients with remnant cancer showing high Casp3 expression had poor outcomes. Our results showed that Casp3 is a potential prognostic marker for non-pCR patients.

Low incidence of MYC/BCL2 double-hit in Burkitt lymphoma

Translocations involving MYC are highly characteristic for Burkitt lymphoma (BL). BCL2 expression has also been found previously in about 10 to 20% of BL cases, and BCL2 translocation is a major mechanism for the deregulation of BCL2 expression in non-Hodgkin lymphomas. However, we know little about the incidence of MYC/BCL2 double-hit (DH) in BL. We examined BL cases to determine how frequently they contained BCL2 translocations in combination with MYC translocations using fluorescence in situ hybridization. We also determined the effect of BCL2 expression on clinical outcomes of BL. BCL2 translocations were detected in 3.5% (2/57 cases) of the cases, and BCL2 expression was detected in 33%. Two cases with BCL2 translocation also showed BCL2 expression. The incidence of BCL2 expression was significantly higher in patients 16 years of age and older (46%) than in patients under 16 years of age (6%). Among patients 16 years of age and older, we did not detect significant differences in overall survival with respect to BCL2 expression status. In conclusion, BCL2 translocation is a rare cytogenetic abnormality in BL, and BL probably accounts for only a small fraction of MYC/BCL2 DH lymphomas. BCL2 expression in BL is probably not associated with BCL2 translocations.

Evaluation of Bcl-2, Bcl-x and Cleaved Caspase-3 in Malignant Peripheral Nerve Sheath Tumors and Neurofibromas

AIMS: To study the expression of Bcl-2, Bcl-x, as well the presence of cleaved caspase-3 in neurofibromas and malignant peripheral nerve sheath tumors. The expression of Bcl-2 and Bcl-x and the presence of cleaved caspase 3 were compared to clinicopathological features of malignant peripheral nerve sheath tumors and their impact on survival rates were also investigated. MATERIALS AND METHODS: The evaluation of Bcl-2, Bcl-x and cleaved caspase-3 was performed by immunohistochemistry using tissue microarrays in 28 malignant peripheral nerve sheath tumors and 38 neurofibromas. Immunoquantification was performed by computerized digital image analysis. CONCLUSIONS: Apoptosis is altered in neurofibromas and mainly in malignant peripheral nerve sheath tumors. High levels of cleaved caspase-3 are more common in tumors with more aggressive histological features and it is associated with lower disease free survival of patients with malignant peripheral nerve sheath tumors.

Expression of JL1 in Burkitt lymphoma is associated with improved overall survival

JL1 is a novel molecule expressed in the surface of hematopoietic precursor cells, but not on any other mature human tissue. Accordingly, JL1 is expressed in acute lymphoblastic leukemia (ALL) cells and can be used both for specific diagnosis and as a target for treatment. However, expression of JL1 by lymphomas has not been thoroughly assessed. Burkitt lymphoma is a potentially curable aggressive lymphoma, but prognostic markers that stratify risk have not been established. We therefore assayed JL1 expression in Burkitt lymphoma patients to assess its value as a prognostic marker for this disease. Tissue microarray blocks of formalin-fixed paraffin-embedded tissue samples from patients with Burkitt lymphoma and other B-cell lymphomas, at the Asan Medical Center and Seoul National University Hospital from January 1998 to December 2008 were immunohistochemically assayed using a mouse monoclonal antibody against JL1. We found that 30.2% of Burkitt lymphoma samples, but no other lymphoma samples, were positive for JL1. JL-1 expression was significantly correlated with patient survival (P = 0.022), but not with other clinical manifestations of the disease, with 91.6% of JL1-positive patients achieving complete remission in response to chemotherapy and 6.25% experiencing disease recurrence. JL1 positivity was significantly correlated with prolonged overall survival by both Kaplan-Meier survival (P = 0.035) and Cox proportional hazard model (P = 0.043) analysis. JL1 expression in Burkitt lymphoma was positively correlated with overall survival and better response to chemotherapy, suggesting that JL1 may be a prognostic marker for risk stratification in these patients.

Caspase 3a: new prognostic marker for diffuse large B-cell lymphoma in the rituximab era

Fewer than half of patients with diffuse large B-cell lymphoma (DLBCL) can be cured. Molecular prognostic factors in the rituximab era must be re-evaluated, because there are few molecular indicators with prognostic value. Samples of DLBCL from 41 newly diagnosed patients with a median follow-up of 52 months were studied. Immunohistochemical staining was performed to investigate the expression of apoptosis-related proteins (Bcl-2 and caspase 3a), cell proliferation (Ki-67), and tumor microenvironmental factors. Two groups were analysed, 23 cases (56%) treated with CHOP and 18 (44%) treated with R-CHOP. Survival analysis showed that cases with overexpression of Bcl-2 had worse overall survival (OS) in the CHOP group. However, OS in the R-CHOP group was adversely affected by lack of caspase 3a staining. In the entire series, cases positive for caspase 3a showed significantly better OS, without significance for other parameters, and caspase 3 was associated with parameters of prognosis and OS in R-CHOP. This is the first study that relates caspase 3a and prognosis in DLBCL.

Circulating Ki-67 index in plasma as a biomarker and prognostic indicator in chronic lymphocytic leukemia

Ki-67 is a nuclear antigen that is expressed in all stages of the cell cycle, except G(0), and is widely used as a marker of cellular proliferation in human tumors. We recently showed that elevated levels of Ki-67 circulating in plasma (cKi-67) are associated with shorter survival in patients with acute lymphoblastic leukemia. The current study included 194 patients with CLL and 96 healthy control subjects. cKi-67 levels in plasma were determined using an electrochemiluminescent immunoassay. We normalized the cKi-67 level to the absolute number of lymphocytes in the patient's peripheral blood to establish the plasma cKi-67 index. The cKi-67 index showed significant correlation with lymph node involvement and Rai stage (P=0.05). Higher cKi-67 index values were significantly associated with shorter survival. Multivariate Cox proportional hazards regression analysis demonstrated that the association of the cKi-67 index with shorter survival was independent of IgV(H) mutation status. In a multivariate model incorporating the cKi-67 index with B2M and IgV(H), only cKi-67 index and B2M levels remained as independent predictors of survival. The results of this study suggest that the plasma cKi-67 index, along with B2M level, is a strong predictor of clinical behavior in CLL.

Upregulation of caspase-3 expression in esophageal cancer correlates with favorable prognosis: an immunohistochemical study from a high incidence area in northern China

Caspase-3 plays an important role as the key effector during apoptosis, but there are very few studies of caspase-3 in esophageal squamous cell carcinoma (ESCC). The purpose of this study was to investigate the expression and prognostic significance of caspase-3 in ESCC from Linzhou City, a high incidence area in northern China. All 64 patients underwent esophagectomy for ESCC between January 2002 and December were enrolled in this study. Caspase-3 expression was assessed by immunohistochemistry (IHC) in primary ESCC and paired normal esophageal epithelium. The positive rate of caspase-3 expression was higher in ESCC than in normal esophageal epithelium (79.7% vs. 50.0%, Chi-square = 12.372, P= 0.001). Caspase-3 expression was correlated with tumor cell differentiation (Phi = 0.717, P < 0.001), tumor infiltration depth (Phi =-0.334, P= 0.008), and pathologic TNM (pTNM) staging (rs =-0.268, P= 0.032). Patients in caspase-3 positive group had a significantly better 5-year overall survival than those in the negative group (77.4% vs. 35.9%, chi(2)= 7.344, P= 0.007). Our results showed that caspase-3 expression was upregulated in ESCC compared with normal esophageal epithelium in population of Chinese high incidence area, and patients with caspase-3 positive expression had better prognosis. Therefore, caspase-3 immunostaining could be a simple and useful tool for predicting survival in ESCC patients.

Reversion of epigenetically mediated BIM silencing overcomes chemoresistance in Burkitt lymphoma

In Burkitt lymphoma/leukemia (BL), achievement of complete remission with first-line chemotherapy remains a challenging issue, as most patients who respond remain disease-free, whereas those refractory have few options of being rescued with salvage therapies. The mechanisms underlying BL chemoresistance and how it can be circumvented remain undetermined. We previously reported the frequent inactivation of the proapoptotic BIM gene in B-cell lymphomas. Here we show that BIM epigenetic silencing by concurrent promoter hypermethylation and deacetylation occurs frequently in primary BL samples and BL-derived cell lines. Remarkably, patients with BL with hypermethylated BIM presented lower complete remission rate (24% vs 79%; P = .002) and shorter overall survival (P = .007) than those with BIM-expressing lymphomas, indicating that BIM transcriptional repression may mediate tumor chemoresistance. Accordingly, by combining in vitro and in vivo studies of human BL-xenografts grown in immunodeficient RAG2(-/-)γc(-/-) mice and of murine B220(+)IgM(+) B-cell lymphomas generated in Eμ-MYC and Eμ-MYC-BIM(+/-) transgenes, we demonstrate that lymphoma chemoresistance is dictated by BIM gene dosage and is reversible on BIM reactivation by genetic manipulation or after treatment with histone-deacetylase inhibitors. We suggest that the combination of histone-deacetylase inhibitors and high-dose chemotherapy may overcome chemoresistance, achieve durable remission, and improve survival of patients with BL.

Circulating Ki-67 protein in plasma as a biomarker and prognostic indicator of acute lymphoblastic leukemia

Tissue-based determination of Ki-67, a marker of cellular proliferation, has shown prognostic value in solid tumors and hematological malignancies. We developed and validated an electrochemiluminescence-based method for sensitive measurement of circulating Ki-67 in plasma (cKi-67). This assay demonstrated significantly higher levels of cKi-67 in patients with newly diagnosed acute lymphoblastic leukemia (ALL) (n=27; median, 762; range, 0-4574U/100 microL) than in healthy control subjects (n=114; median, 399; range, 36-2830U/100 microL). Moreover, elevated plasma cKi-67 was associated with significantly shorter survival in ALL patients (P=0.05). These findings suggest that Ki-67 can be detected in circulation and has potential for use as a biomarker for predicting clinical behavior in ALL.