Tumor Proliferation Rate Research Articles

TU‐C‐BRB‐07: Incorporation of Angiogenesis Into a Stochastic Imaging‐Based Tumor Vasculature Model

Aim Controlling interaction between tumor growth and vasculature development are the basis of anti‐angiogenic therapies. A model simulating tumor growth and angiogenesis was developed and the tumor oxygenation status was evaluated with respect to two parameters: tumor proliferation rate (TPR) and endothelial cell proliferation rate (EPR). Methods and Materials Our previous image‐based model of vasculature was expanded by incorporating angiogenic development. The tissue volume encapsulating the tumor and vasculature was simulated as a MATLAB matrix. Vessels were simulated to sprout from the existing vasculature towards the tumor driven by hypoxia‐induced growth factors. The relative magnitude of TPR and EPR determined the simulation time steps. Xenografted and spontaneous tumors were simulated and the tumor oxygenation status was evaluated with respect to TPR & EPR. The model was verified against the experimental data obtained from CE‐CT and Cu‐ATSM PET imaging. Results The time‐dependant growth of vessels towards hypoxic regions in the tumor was demonstrated. TPR was found to have the most profound impact on development of hypoxia and heterogeneity of the oxygen concentration inside the tumor. Higher TPR led to faster development of hypoxia. Due to the limited vasculature available, xenografted tumors become hypoxic faster than spontaneous tumors for similar TPRs. When comparing simulations to the experiments, the overall development of vasculature and consequent hypoxia matched well with the imaging data. Conclusions A model capable of simulating temporal development of tumor and vasculature has been developed and tested on the imaging‐derived experimental data. The presented model has a potential to study the response of tumor and the vasculature to therapy, which can be a valuable input for optimizing anti‐angiogenic therapies.

The Influence of Socioeconomic Disparities on Breast Cancer Tumor Biology and Prognosis: A Review

Socioeconomic deprivation is associated with an increased risk of breast cancer mortality. This article summarizes the relationships between socioeconomic status (SES) and breast cancer in white European women compared with racial and ethnic groups in the United States. Furthermore, we examine the association between obesity and breast cancer within socioeconomic disparities. Mortality rates were published by the American Cancer Society and the National Cancer Institute Surveillance, Epidemiology, and End Results Program. Obesity data were derived from the National Center for Health Statistics Behavioral Risk Factor Surveillance System. MEDLINE searches were performed using keywords, such as socioeconomic status, poverty, African American, Hispanic, race, and combined with related articles. Socioeconomic deprivation may be responsible for the increased risk of breast cancer mortality in African American and Hispanic patients, as they are more likely than white American patients to be diagnosed with advanced disease. Among white women, social deprivation is related to poor breast cancer prognosis, with increased prevalence rates of high-grade, estrogen receptor (ER)-negative tumors, similar to that of triple-negative breast cancers observed in African American and Hispanic women. Obesity is associated with advanced breast cancer at diagnosis, high tumor proliferation rates, and more triple-negative phenotypes, indicating that it may adversely contribute to prognosis. Most studies show an effect of SES on breast cancer incidence and prognosis. Research should focus on the influence of social deprivation on breast cancer characteristics, such as absence of ER expression, that occurs in African Americans and Hispanics and in white European women with a different genetic background.

Autowaves in a model of invasive tumor growth

A mathematical model for invasive tumor growth is proposed, which takes into account cell division, death, and motility. The model includes local cell density and the distribution of nutrient (oxygen) concentration. Cancer cells die in the absence of nutrients; therefore, the distribution of oxygen in tissue substantially affects both the tumor proliferation rate and its structure. The model adequately describes the experimentally measured rate of tumor proliferation. The existence of autowave solutions is demonstrated, and their properties are investigated. The results are compared with the properties of the Kolmogorov-Petrovskii-Piskunov and Fisher equations. It is shown that the nutrient distribution influences the selection of speed and the convergence of the initial conditions to the automodel solution.

GLUT1 Expression Is Increased in Hepatocellular Carcinoma and Promotes Tumorigenesis

Accelerated glycolysis is one of the biochemical characteristics of cancer cells. The glucose transporter isoform 1 (GLUT1) gene encodes a key rate-limiting factor in glucose transport into cancer cells. However, its expression level and functional significance in hepatocellular cancer (HCC) are still disputed. Therefore, we aimed to analyze the expression and function of the GLUT1 gene in cases of HCC. We found significantly higher GLUT1 mRNA expression levels in HCC tissues and cell lines compared with primary human hepatocytes and matched nontumor tissue. Immunohistochemical analysis of a tissue microarray of 152 HCC cases revealed a significant correlation between Glut1 protein expression levels and a higher Ki-67 labeling index, advanced tumor stages, and poor differentiation. Accordingly, suppression of GLUT1 expression by siRNA significantly impaired both the growth and migratory potential of HCC cells. Furthermore, inhibition of GLUT1 expression reduced both glucose uptake and lactate secretion. Hypoxic conditions further increased GLUT1 expression levels in HCC cells, and this induction was dependent on the activation of the transcription factor hypoxia-inducible factor-1alpha. In summary, our findings suggest that increased GLUT1 expression levels in HCC cells functionally affect tumorigenicity, and thus, we propose GLUT1 as an innovative therapeutic target for this highly aggressive tumor.

Induction of apoptosis in tumor cells as a mechanism of tumor growth reduction in allergic mice

Cancer is the leading cause of mortality worldwide. Analysis of epidemiological data has revealed a negative relationship between allergic conditions and cancer incidence. This study addresses the effects of chronic antigen ingestion by sensitized mice (allergy) on Ehrlich tumor growth in mouse footpad. Mice were sensitized (allergic) or not (sham) with ovalbumin and challenged orally with egg white solution. After one week of oral challenge, all mice were inoculated with experimental Ehrlich tumor (EET) cells in the footpad, and tumor growth was evaluated for 21 days. A decrease in tumor growth occurred, as assessed by paw thickness in the allergic group, which was associated with smaller areas of necrosis, reduced infiltration of neutrophils, and reduced levels of IFN-γ, IL-4, and IL-10. Although, the tumor proliferation rate was similar in both groups, an increase in apoptosis occurred in allergic mice. In conclusion, analysis of the data obtained allows us to suggest that a concomitant allergic condition would reduce tumor progression through increased tumor cell apoptosis, accompanied by reduced areas of necrosis at the tumor site. Indeed, such findings suggested a possible mechanism for the reduced cancer incidence observed in allergic individuals.

Advances in neuroimaging techniques for the evaluation of tumor growth, vascular permeability, and angiogenesis in gliomas

This review will summarize new neuroimaging techniques, particularly MRI and PET imaging, that can be used to assess brain tumor growth and angiogenesis. Glioma tumor vasculature is abnormal, and advances in MRI now permit visualization of the hemodynamic properties of gliomas including cerebral blood volume and blood flow, vascular permeability, and blood vessel diameter. New radiolabeled PET tracers have allowed more specific interrogation of glioma physiology such as hypoxia assessment or tumor proliferation rate. These two techniques are complementary and will likely yield important information on tumor response to therapy, particularly in the setting of antiangiogenic agents, which confound the interpretation of standard contrast-enhanced MRI scans. These techniques may allow development of patient-specific therapy to improve outcome in patients with gliomas.

Synergistic antitumoral activity and induction of apoptosis by novel pan Bcl-2 proteins inhibitor apogossypolone with adriamycin in human hepatocellular carcinoma

To investigate the in vitro and in vivo activities and related mechanism of apogossypolone (ApoG2) alone or in combination with adriamycin (ADM) against human hepatocellular carcinoma (HCC). The IC50 of ApoG2 in vitro was tested by WST assay, and the synergistic effect was analyzed using the CalcuSyn method. Cell apoptosis was determined using 4',6-diamidino-2- phenylindole staining and flow cytometric analysis. Western blotting was used to determine the expression of apoptosis-related proteins. In vivo activity was evaluated in the xenograft model in nude mice, and apoptosis in tumor tissues was determined by terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling (TUNEL) assay. The IC50 of ApoG2 in HCC cells was 17.28-30.63 micromol/L. When ApoG2 was combined with ADM, increased cytotoxicity and apoptosis were observed in SMMC-7721 cells compared to treatment with ApoG2 alone. The Western blotting results indicated that the ApoG2 induced apoptosis in SMMC-7721 cells by downregulating anti-apoptotic proteins Bcl-2, Mcl-1, and Bcl-XL, up-regulating pro-apoptotic protein Noxa, and promoting the activities of caspases-9 and -3. The tumor growth of xenograft SMMC-7721 was inhibited in nude mice when ApoG2 was administered orally without causing damage to the normal tissues. The in vivo study also indicated an increasing anti-tumoral effect when ApoG2 at 100 or 200 mg/kg dosages were used together with ADM at 5.5 mg/kg, with relative tumor proliferation rate (T/C) values of 0.456 and 0.323, respectively. Apoptosis induced in vivo by ApoG2 alone or combined with ADM was confirmed by TUNEL assay in tumor tissues. ApoG2 is a potential non-toxic target agent that induces apoptosis by upregulating Noxa, while inhibiting anti-apoptotic proteins and promoting the effect of chemotherapy agent ADM in HCC.

Effects of combination treatment of bortezomib and dexamethasone in SCCHN cell lines depend on tumor cell specificity.

Bortezomib has recently become the new treatment standard for relapsed or refractory multiple myeloma. We previously demonstrated that bortezomib also had a significant growth-inhibiting and apoptotic effect on squamous cell carcinoma of the head and neck (SCCHN) cells in vitro. Preclinical evidence has provided a rationale for combining bortezomib with dexamethasone in multiple myeloma, suggesting that the therapeutic effects of the two agents might be additive. These findings are in contrast with the results achieved in solid tumor models where the addition of dexamethasone reduced the efficacy of other antineoplastic drugs. In the present study, we investigated the effect of dexamethasone in combination with bortezomib in SCCHN cell lines for the first time. The antiproliferative effect of bortezomib alone or in combination with increasing concentrations of dexamethasone was investigated in four SCCHN cell lines. Cell growth inhibition and viability were measured quantitatively using WST and LDH assays. Bortezomib alone inhibited the growth of all four SCCHN cell lines significantly (p<0.047). The addition of dexamethasone leads to a clear tumor cell decline and showed a trend in enhancing the growth-inhibitory effect of bortezomib although the difference failed to reach statistical significance (p>0.05). Our first results show that dexamethasone increased the cytotoxic activity of bortezomib in most SCCHN cell lines investigated. These findings might be dependent on molecular factors such as the degree of tumor cell differentiation and proliferation rate. Therefore, further studies will be required to elucidate these molecular factors to substantiate our findings from a cancer biological point of view.

Design, synthesis and antitumor evaluation of novel thalidomide dithiocarbamate and dithioate analogs against Ehrlich ascites carcinoma-induced solid tumor in Swiss albino mice

A series of 16 novel thalidomide sulfur analogs containing one and two sulfur atoms 2 and 4– 18, respectively, were designed and synthesized. These compounds were screened for in vitro antitumor activity against Ehrlich ascites carcinoma (EAC) cell line and exhibited potent cytotoxic activity. On the bases of the obtained results for in vitro cytotoxic activity, thalidomide sulfur analogs containing two sulfur atoms 8, 9, 13 and 14 were selected and tested in vivo against EAC-induced solid tumor in female mice compared to thalidomide 1 as well as its analog 2 and exhibited a highly significant reduction in tumor volume (TV). Results illustrated the antioxidative activity of these compounds as the level of hepatic lipid peroxidation decreased and levels of antioxidant enzymes like superoxide dismutase (SOD) and catalase were elevated. The histopathological investigations revealed that thalidomide sulfur analogs 2, 8, 9, 13 and 14 have antimitotic, apoptotic and necrotic activities against solid tumor. These compounds lead to increase of Fas-L expression. The immunohistochemical studies showed a decrease in Ki67 and vascular endothelial growth factor (VEGF) staining in tumor cells from treated-animals when compared with non-treated groups, which suggests an inhibition of tumor proliferation rate and angiogenic process associated with tumor growth. Compounds 9 and 13 were the most potent compounds in tumor necrosis without liver necrosis. At the same time, treatment with compound 9 resulted in liver degeneration.

The Targeted Oncolytic Poxvirus JX-594 Demonstrates Antitumoral, Antivascular, and Anti-HBV Activities in Patients With Hepatocellular Carcinoma

JX-594 is a targeted oncolytic poxvirus that is designed to eradicate cancer cells having cell-cycle defects, through replication, cell lysis, and spread within tumors; oncolysis-induced tumor vascular shutdown and immunostimulation are augmented by granulocyte monocyte-colony-stimulating factor (GM-CSF) transgene expression. We have previously shown, in animal models of hepatocellular carcinoma (HCC), that JX-594 is a promising anticancer agent. We tested JX-594 in three patients with advanced refractory hepatitis B virus (HBV)-associated HCC through intratumoral administration. JX-594 treatment was well-tolerated and resulted in antitumoral efficacy in all three patients, despite the presence of high levels of neutralizing antibodies. JX-594 replication, its release into the circulation, distant tumor targeting were demonstrated. JX-594 administration resulted in the induction of antivascular cytokines, and was associated with tumor vascular shutdown. We also showed, for the first time, that oncolytic virotherapy can suppress underlying HBV replication in HCC patients, and that tumor tissue could be the primary source of acute HBV replication and acute post-treatment HBV release. JX-594 treatment in HBV-associated HCC warrants further clinical testing; a Phase II trial is underway.

Expression of stem cell factor (SCF), a KIT ligand, in gastrointestinal stromal tumors (GISTs): A potential marker for tumor proliferation

Gastrointestinal stromal tumors (GISTs) show a high incidence of gain-of-function mutations of the c-kit gene, which encodes a receptor tyrosine kinase KIT. This mutation is seen independently of metastasis and/or recurrence of tumors; thus, the factors involved in tumor proliferation rate and malignancy are still not known. Some mesenchymal and epithelial tumors have been reported to co-express KIT and its ligand, stem cell factor (SCF), for autonomous proliferation by the autocrine mechanism. The purpose of this study is to clarify whether GIST cells produce SCF, despite mutated KIT with constitutive activation. Immunohistochemically, we examined the co-expression of KIT and SCF in 36 GIST cases. All cases were found to be KIT-positive, and of these, 21 cases, including four recurrent or metastatic GISTs, showed co-expression of SCF. MIB-1 labeling index was significantly higher, and the average tumor size was larger in SCF-positive cases. By confocal microscopy, KIT was expressed on the cellular membrane, around which SCF was distributed less densely. Western blot analysis revealed that the membrane-bound SCF of 31 kDa was found to be approximately 10 times more abundant than the soluble SCF of 18.5 kDa, suggesting continuous KIT activation. These results indicate that proliferation of GIST cells can be caused not only by the gain-of-function mutation of c-kit, but also by the autocrine mechanism of the SCF/KIT system. Thus, SCF expression would be a useful marker for tumor proliferation.

Expression of tenascin-c and CD44 receptors in cardiac myxomas

Myxomas are the most frequent primary cardiac neoplasms. They have an abundant extracellular matrix rich in proteoglycans. Interactions between cells and matrix are very important in the development of tumors, but data about myxomas in this setting are scarce because of the rarity of such neoplasms. The expression of tenascin-c and hyaluran receptors in cardiac myxoma has never been investigated. Moreover, it is now well recognized that cells of cardiac myxoma differentiate along endothelial lines. We have analyzed left atrial myxomas from 13 consecutive patients (six male and seven female, surgically treated), via immunohistochemical methods for the expression of molecules also implicated in angiogenesis in normal and pathological conditions, like tenascin-c and hyaluran receptors CD44s, CD44v5 and CD44v6. Our data suggest that tenascin-c and CD44s play a synergic and perhaps complementary role in development of cardiac myxomas. In particular, tenascin-c seems to promote aggregation of cells and differentiation in vascular structures, whereas CD44s receptors might be important for cellular motility. Cell proliferation rate in such tumors was very low (MIB-1 labeling index <1%) and uniform in all the areas of the neoplasms regardless of the presence of characteristic structures such as cords and rings of multinucleated cells or the expression of tenascin-c and CD44 receptors. This study shows that cardiac myxomas express in the extracellular matrix tenascin-c and on the cellular membranes of neoplastic cells the hyaluran receptor CD44s. Such molecules take part in the mechanism of development of the myxomas and might be in the future the target of nonsurgical treatments.

In vivo MRS markers of response to CHOP chemotherapy in the WSU-DLCL2 human diffuse large B-cell lymphoma xenograft.

To identify 1H-MRS molecular biomarkers of early clinical therapeutic response in non-Hodgkin's lymphoma, an in vivo longitudinal study was performed on human non-Hodgkin's diffuse large B-cell lymphoma xenografts (WSU-DLCL2) grown in the flanks of female SCID mice. 31P-MRS measurements, which have been demonstrated to be prognostic clinical indices of response (Arias-Mendoza et al. Acad. Radiol. 2004; 11: 368-376) but which provide lower spatial resolution, were included for comparison. The animals received CHOP (cyclophosphamide, hydroxydoxorubicin, oncovin and prednisone) chemotherapy for three 1-week cycles, resulting in stable disease based on tumor volume. Localization of total choline and phosphorus metabolites in vivo was achieved with stimulated echo acquisition mode and image selected in vivo spectroscopy sequences, respectively. Significant decreases in lactate were detected by the selective multiple quantum coherence spectral editing technique after the first cycle of CHOP, whereas total choline and the phosphomonoester/nucleoside triphosphate ratio did not change until the third cycle. Ex vivo extract MRS of tumors corroborated the in vivo results. Histological staining with antibodies to Ki67 revealed a decrease in proliferation rate in CHOP-treated tumors that coincided with the decrease in lactate. This study demonstrates the utility of lactate as an early proliferation-sensitive indicator of therapeutic response in a mouse model of non-Hodgkin's lymphoma and serves as a basis for future clinical implementation of these methods.

In vivofate and therapeutic efficacy of PF‐4/CTF microspheres in an orthotopic human glioblastoma model

The correlation between glioma grade and angiogenesis suggests that antiangiogenic therapies are potentially therapeutically effective for these tumors. However, to achieve tumor suppression, antiangiogenic therapies need to be administered daily using high systemic quantities. We designed a biodegradable polymeric device that overcomes those barriers by providing sustained local delivery of a C-terminal fragment of platelet factor 4 (PF-4/CTF), an antiangiogenic agent. Fluorescent-labeled microspheres composed of poly lactic-coglycolic acid (PLGA) were loaded with rhodamine-labeled PF-4/CTF and formulated to release their contents over time. Fluorescent labeling enabled the correlation between the in vitro to the in vivo kinetic and release studies. PF-4/CTF microspheres were injected into established intracranial human glioma tumors in nude mice. Noninvasive magnetic resonance imaging (MRI) was used to assess the therapeutic response. Tumor size, microvessel density, proliferation, and apoptosis rate were measured by histological analysis. Intracranially, the microspheres were located throughout the tumor bed and continuously released PF-4/CTF during the entire experimental period. MRI and histological studies showed that a single injection of microspheres containing PF-4/CTF caused a 65.2% and 72% reduction in tumor volume, respectively, with a significant decrease in angiogenesis and an increase in apoptosis. Our data demonstrate that polymeric microspheres are an effective therapeutic approach for delivering antiangiogenic agents that result in the inhibition of glioma tumor growth.

Her2 and Progesterone Receptor Status Are Not Predictive of Response to Fulvestrant Treatment

It has been hypothesized that response to endocrine therapy for breast cancer depends on Her2 and progesterone receptor status, grading, and tumor proliferation rate. In this study, we evaluated factors that are potentially predictive of response and time to progression in patients treated with fulvestrant. One hundred fifty-five patients were included and followed prospectively. Patients received fulvestrant at standard dose by i.m. injection. Response was evaluated every 3 months using International Union Against Cancer criteria. Time to progression and overall survival were estimated with the Kaplan-Meier product limit method. A multivariate analysis was done to evaluate factors potentially influencing response and time to progression. We observed a partial response in 19 patients (12.3%), stable disease > or =6 months in 56 patients (36.1%), stable disease >3 months but <6 months in 7 patients (4.5%), and progressive disease in 73 patients (47.1%). Median time to progression was 5 months, and median overall survival was 27 months. Probability of achieving clinical benefit was significantly associated with a low proliferation rate (P = 0.015), nonvisceral metastatic sites (P = 0.023), and first-line therapy (P = 0.023). First-line therapy was also associated with prolonged time to progression (P = 0.003). Response rate and time to progression are shown to be independent of Her2 status, grading, and progesterone receptor status. This is probably caused by the unique mechanism of action associated with fulvestrant: Due to receptor down-regulation, it blocks nuclear, cytoplasmatic, and membrane-bound estrogen receptor. Therefore, it seems to inhibit the cross-talk between growth factor receptor signaling and estrogen receptor in a more effective manner.

Efficacy and toxicity of dose-adjusted EPOCH-rituximab in adults with newly diagnosed Burkitt lymphoma

8035 Background: Burkitt Lymphoma (BL) is a rare and highly aggressive lymphoma, characterized by a high tumor proliferation rate. While the standard therapy of BL is highly effective, it involves intensive, multi-agent chemotherapy that is associated with considerable treatment-related toxicity and mortality, especially in older patients. We hypothesized that the regimen DA-EPOCH may be effective in BL, based on the observation that it overcomes the adverse effect of high proliferation in diffuse large B-cell lymphoma. Methods: We investigated DA-EPOCH-rituximab (R) in untreated BL in an attempt to maintain the high cure rates of standard therapy with minimal treatment related toxicity. Eligible patients had a diagnosis of untreated BL and could be HIV negative or positive with HIV negative patients (n=13) receiving 6 cycles of DA-EPOCH-R as previously described (Blood 99: 2685, 2002) and HIV positive (n=6) patients receiving 3–6 cycles of DA- EPOCH-R for 1 cycle beyond CR for a minimum of 3 cycles. All patients received intrathecal methotrexate prophylaxis and outpatient therapy where possible. Results: The characteristics of 19 enrolled patients are: median age (range) 29 (18–66) and ECOG PS 1(1–3); stage III/IV 10 (53%); LDH &gt; N 11 (61%); male sex 15 (79%); extranodal sites 13 (68%) and ileocecal disease 13 (68%). No patients so far had CNS involvement at diagnosis. Response is CR/CRu in 100% of patients with one patient receiving consolidative radiotherapy to a site of residual disease. OS and PFS are both 100% and EFS 93.3% at a median potential follow-up time of 29 months. Toxicities were fever/neutropenia in 16%, grade 4 neutropenia in 47% and grade 3/4 thrombocytopenia in 22% of cycles. There was one case of tumor lysis syndrome and no treatment related deaths. Conclusions: DA-EPOCH-R is highly effective in BL. It appears to be associated with much lower toxicity compared to standard high-dose regimens and may significantly advance the therapeutic index of BL treatment. Accrual continues. No significant financial relationships to disclose.

Point mutations and genomic deletions in CCND1 create stable truncated cyclin D1 mRNAs that are associated with increased proliferation rate and shorter survival

AbstractA gene expression signature of tumor proliferation rate in mantle cell lymphoma (MCL) is an overriding molecular predictor of the length of survival following diagnosis. Many strongly proliferative MCL tumors have exceptionally high cyclin D1 mRNA levels and preferentially express short cyclin D1 mRNA isoforms. We demonstrate here that these short mRNAs are cyclin D1a isoforms with truncated 3′UTRs, not alternatively spliced cyclin D1b mRNA isoforms. Among 15 MCL tumors with truncated cyclin D1 mRNAs, 7 had genomic deletions in the CCND1 3′UTR region. In 3 others, CCND1 contained point mutations that created premature polyadenylation signals, giving rise to 1.5-kb mRNAs lacking most of the 3′UTR. Both types of genomic alteration created transcripts lacking mRNA destabilization elements present in the wild-type cyclin D1a mRNA. Premature polyadenylation due to a 3′UTR mutation also was present in the Z-138 MCL cell line, which expressed both truncated and full-length cyclin D1a mRNAs. In these cells, the half-life of the short cyclin D1a mRNA was much longer than that of the full-length mRNA. We conclude that alterations of CCND1 3′UTR structure can significantly increase its oncogenic effect and worsen the clinical course of MCL patients.

Distinct Clinical and Pathological Features Are Associated with the BRAFT1799A(V600E) Mutation in Primary Melanoma

The BRAF(T1799A) mutation encodes BRAF(V600E) that leads to activation of the mitogen-activated protein kinase pathway. This study aimed to assess the clinico-pathological features of primary invasive melanomas containing the BRAF(T1799A) mutation. Patients (n=251) with invasive primary melanomas from Australia were interviewed and examined with respect to their melanoma characteristics and risk factors. Independent review of pathology, allele-specific PCR for the BRAF(T1799A) mutation, immunohistochemical staining with Ki67, and phospho-histone-H3 (PH3) were performed. The BRAF(T1799A) mutation was found in 112 (45%) of the primary melanomas. Associations with the BRAF(T1799A) mutation (P<0.05) were as follows: low tumor thickness (odds ratio (OR)=3.3); low mitotic rate (OR=2.0); low Ki67 score (OR=5.0); low PH3 score (OR=3.3); superficial spreading melanoma (OR=10.0); pigmented melanoma (OR=3.7); a lack of history of solar keratoses (OR=2.7); a location on the trunk (OR=3.4) or extremity (OR=2.0); a high level of self-reported childhood sun exposure (OR=2.0); < or =50 years of age (OR=2.5); and fewer freckles (OR=2.5). We conclude that the BRAF(T1799A) mutation has associations with host phenotype, tumor location, and pigmentation. Although implicated in the control of the cell cycle, the BRAF(T1799A) mutation is associated with a lower rate of tumor proliferation.

Bromodeoxyuridine Labeling Index as an Indicator of Early Tumor Response to Preoperative Radiotherapy in Patients with Rectal Cancer

PurposeAssessment of tumor proliferation rate using Bromodeoxyuridine labeling index (BrdUrdLI) as a possible predictor of rectal cancer response to preoperative radiotherapy (RT). Methods and materialNinety-two patients were qualified either to short RT (5 Gy/fraction/5 days) and surgery about 1 week after RT (schedule I), or to short RT and 4–5 weeks interval before surgery (schedule II). Tumor samples were taken twice from each patient: before RT and at the time of surgery. The samples were incubated with BrdUrd for 1 h at 37°C, and the BrdUrdLI was calculated as a percentage of BrdUrd-labeled cells. ResultsThirty-eight patients were treated according to schedule I and 54 patients according to schedule II. Mean BrdUrdLI before RT was 8.5% and its value did not differ between the patients in the two compared groups. After RT tumors showed statistically significant growth inhibition (reduction of BrdUrdLI). As the pretreatment BrdUrd LI was not predictive for early clinical and pathologic tumor response, prognostic role of the ratio of BrdUrdLI after to BrdUrdLI before RT was considered. The ratios were calculated separately for fast (BrdUrd LI > 8.5%) and slowly (BrdUrd LI ≤ 8.5%) proliferating tumors and correlated with overall treatment time (OTT, i.e., time from the first day of RT to surgery). One month after RT, accelerated proliferation was observed only in slowly proliferating tumors. ConclusionsPretreatment BrdUrdLI was not predictive for early clinical and pathologic tumor response. The ratio after/before RT BrdUrdLI was correlated to inhibition of proliferation in responsive tumors.

Antiproliferative and apoptotic effects of mycophenolic acid in human B-cell non-Hodgkin lymphomas

Mycophenolic acid (MPA)/mycophenolate mofetil (MMF), a powerful immunosuppressive agent was tested on human B-lymphoma cells (Epstein-Barr virus +/−) in vitro and in SCID mouse xenograft model. Proliferation, apoptotic activity and tumor volume were evaluated. MPA inhibited lymphoma cell proliferation and induced apoptosis (50–60% at 72 h). In vivo, oral administration significantly inhibited subcutaneous tumor growth. Immunohistochemistry showed significantly decreased proliferation rate and higher apoptotic activity in tumors treated with MMF. Xenografted lymphoma cells remained sensitive to MPA. Our results suggest that MPA may be recommended as an additional component of lymphoma chemotherapeutical regimens, with special considerations to post-transplant lymphomas.