Antisense oligonucleotide-mediated MDM4 exon 6 skipping impairs tumor growth

MDM4 is a promising target for cancer therapy, as it is undetectable in most normal adult tissues but often upregulated in cancer cells to dampen p53 tumor-suppressor function. The mechanisms that underlie MDM4 upregulation in cancer cells are largely unknown. Here, we have shown that this key oncogenic event mainly depends on a specific alternative splicing switch. We determined that while a nonsense-mediated, decay-targeted isoform of MDM4 (MDM4-S) is produced in normal adult tissues as a result of exon 6 skipping, enhanced exon 6 inclusion leads to expression of full-length MDM4 in a large number of human cancers. Although this alternative splicing event is likely regulated by multiple splicing factors, we identified the SRSF3 oncoprotein as a key enhancer of exon 6 inclusion. In multiple human melanoma cell lines and in melanoma patient-derived xenograft (PDX) mouse models, antisense oligonucleotide-mediated (ASO-mediated) skipping of exon 6 decreased MDM4 abundance, inhibited melanoma growth, and enhanced sensitivity to MAPK-targeting therapeutics. Additionally, ASO-based MDM4 targeting reduced diffuse large B cell lymphoma PDX growth. As full-length MDM4 is enhanced in multiple human tumors, our data indicate that this strategy is applicable to a wide range of tumor types. We conclude that enhanced MDM4 exon 6 inclusion is a common oncogenic event and has potential as a clinically compatible therapeutic target.

Carotid artery inflammation associated with gemcitabine-based therapy: a special report

Vasculitis is an inflammation that can present as acute or chronic in nature, which causes changes in the walls of blood vessels, including thickening, weakening, narrowing and scarring. Gemcitabine, an antimetabolite chemotherapeutic agent, is generally well tolerated with a favorable side effect profile. However, there is increasing evidence that it is associated with vasculitis, which can affect small and large vessels. In this case report, we report a patient who has experienced fever with severe tenderness over right carotid artery, which occurred on the fifth day after the administration of gemcitabine. The exact mechanism of gemcitabine-induced vasculitis is unknown but cessation of gemcitabine and initiation of anti-inflammatory treatment appears to aid in the resolution of the clinical syndrome.

Gender and ethnic differences in incidence and survival of lymphoid neoplasm subtypes in an Asian population: Secular trends of a population-based cancer registry from 1998 to 2012

Descriptive epidemiology on incidence and survival by lymphoid neoplasm (LN) subtypes using the 2008 World Health Organisation (WHO) classification remained limited in Asia. The aim of this study was to evaluate whether gender and ethnic differences in incidence and survival of LN subtypes existed using the Singapore Cancer Registry (SCR) from 1998 to 2012. We derived age standardised incidence rates (ASIRs) by the direct standardisation method and 5-year relative survival (RSR) by the Ederer II method and period approach. Five-year observed survival (OS) was obtained for each ethnicity. Malays had the highest ASIR of total LNs among the three ethnicities for each time period. The largest increase in 5-year RSR subtypes was follicular lymphoma from 43.8% in 1998-2002 to 82.3% in 2008-2012; followed by chronic lymphocytic leukaemia (CLL)/small lymphocytic lymphoma (SLL) from 48.1% in 1998-2002 to 77.9% in 2008-2012. Although males had higher incidence than females in each time period, females had greater 5-year RSR for follicular lymphoma (89.8% in 2008-2012 for females vs. 76.6% in 2008-2012 for males) and CLL/SLL (78.7% in 2008-2012 for females vs. 76.7% in 2008-2012 for males). All three ethnicities experienced an overall increase in 5-year OS for mature B-cell lymphoma, with Indians experiencing the greatest increase (37.1% in 1998-2002 to 61.1% in 2008-2012), followed by Malays (30.8% in 1998-2002 to 48.7% in 2008-2012) and then Chinese (36.4% in 1998-2002 to 51.3% in 2008-2012). Our study demonstrated that improved mature B-cell lymphoma survival was not only observed in the West, but also in Singapore.

A Pilot Study to Evaluate the Role of Therapeutic Drug Monitoring of Pegfilgrastim in Lymphoma Patients Receiving Chemotherapy

Background:

Despite primary prophylaxis of febrile neutropenia (FN) with pegfilgrastim, studies have demonstrated a significant number of breakthrough FN events among Asian lymphoma patients receiving chemotherapy. This study was designed to investigate the association of pegfilgrastim concentrations during the lowest point of absolute neutrophil count (ANC nadir) after chemotherapy administration and the occurrence of breakthrough FN, to evaluate whether Therapeutic drug monitoring of pegfilgrastim can guide management of FN.

Methods:

This was a single-centre, prospective cohort study of Asian lymphoma patients who received prophylactic pegfilgrastim after completion of their chemotherapy. Pegfilgrastim serum concentrations were measured from blood samples taken during ANC nadir and at development of breakthrough FN using an enzyme-linked immunosorbent assay. Descriptive statistics, t-tests and correlation curves were used in the statistical analyses.

Results:

Nineteen patients were recruited from May to August 2012 and received 21 cycles of pegfilgrastim. Three (15.8%) developed breakthrough FN. The median pegfilgrastim concentration among patients who developed breakthrough FN was 0.257 (0.231–0.631) ng/ml, compared to 0.299 (0.001–0.829) ng/ml in patients who did not (p=0.740). Baseline ANC levels were significantly lower in patients with breakthrough FN (3.59 × 109/L, range 2.71–3.87) versus those who did not (5.36 × 109/L, range 2.80–16.48; p=0.014).

Conclusion:

There was no difference in pegfilgrastim levels during ANC nadir between patients who developed breakthrough FN and those who did not, but the study was underpowered. Therapeutic drug monitoring of pegfilgrastim cannot be recommended at this time.

Management of B-cell non-Hodgkin lymphoma in Asia: resource-stratified guidelines

Treatment of B-cell non-Hodgkin lymphomas has undergone substantial developments in the past 10 years. The introduction of rituximab has greatly improved survival outcomes in patients. Clinical practice guidelines based on current evidence have been developed to provide recommendations for standard treatment approaches. However, guidelines do not take into account resource limitations in resource-poor countries. The huge disparities in economy, health-care infrastructure, and access to novel drugs between Asian countries can hinder the delivery of optimum care to patients with lymphoma in Asia. We outline guidelines appropriate to different levels of health-care resources and expertise, aiming to provide advice on diagnosis and treatment, unify interpretation of results, and allow the design of future studies in Asia. In this resource-adapted consensus, we summarise recommendations for diagnosis, staging, risk stratification, and treatment of common B-cell non-Hodgkin lymphomas in Asia.

Angiogenesis and hematological malignancies

Since the initial hypotheses on the importance of angiogenesis in the pathogenesis of cancer approximately 30 years ago, there have been major advances in the understanding of the cellular and molecular mechanisms involved in the regulation of this complex process of new vessel formation. Among the multitude of factors, vascular endothelial growth factor (VEGF) has emerged as one of the most potent angiogenic factors, being implicated in the initiation of signal transduction responsible for cell proliferation, survival, migration and adhesion. Inhibition of VEGF and its signaling pathway offers a potential new molecular target in cancer therapy. This article reviews the role of angiogenesis and its mediators, particularly vascular endothelial growth factors, in hematological malignancies, as well as the potential use of anti-angiogenic therapies in the management of these conditions.

Brain metastasis in sarcoma: Does metastasectomy or aggressive multi-disciplinary treatment improve survival outcomes

AIM

Brain metastasis is rare in sarcoma. Prognostic factors, optimal management strategies and therapeutic outcomes of such patients are not well studied. We aimed to evaluate the incidence, clinical characteristics and treatment outcomes of parenchymal brain metastasis in sarcoma patients.

METHODS

This is a single center retrospective analysis. Overall survival (OS) was calculated from the time of diagnosis of brain metastasis to time of death.

RESULTS

Sixteen patients (2.1%) with complete electronic medical records treated at our institution from 2002 to 2010 were identified. Median age was 52 years; 88% had additional sites of metastases. Eight different subtypes of soft tissue and bone sarcoma were identified. Eighty-one percent of the patients developed metachronous brain metastasis at a median of 14 months after initial sarcoma diagnosis. Thirty-eight percent of patients had solitary brain metastasis and 44% underwent aggressive therapy for brain metastasis, defined as either surgical resection or multimodality treatment. The remaining 56% received conservative treatment (either whole brain radiation alone, chemotherapy alone or best supportive care). Median OS for the entire cohort was 3.5 months (95% CI 1.1-6.3 months). A trend toward improved OS was observed with an aggressive treatment approach, 3.7 months versus 1.2 months (P = 0.077) and the usage of chemotherapy (P = 0.071).

CONCLUSION

Brain metastasis in sarcoma is rare, usually coexists with significant systemic disease and is associated with a grave prognosis. Use of chemotherapy and an aggressive treatment approach in well-selected patients may be associated with improved survival. Prospective studies are needed to confirm these findings.

Janus kinase 3-activating mutations identified in natural killer/T-cell lymphoma

The molecular pathogenesis of natural killer/T-cell lymphoma (NKTCL) is not well understood. We conducted whole-exome sequencing and identified Janus kinase 3 (JAK3) somatic-activating mutations (A572V and A573V) in 2 of 4 patients with NKTCLs. Further validation of the prevalence of JAK3 mutations was determined by Sanger sequencing and high-resolution melt (HRM) analysis in an additional 61 cases. In total, 23 of 65 (35.4%) cases harbored JAK3 mutations. Functional characterization of the JAK3 mutations support its involvement in cytokine-independent JAK/STAT constitutive activation leading to increased cell growth. Moreover, treatment of both JAK3-mutant and wild-type NKTCL cell lines with a novel pan-JAK inhibitor, CP-690550, resulted in dose-dependent reduction of phosphorylated STAT5, reduced cell viability, and increased apoptosis. Hence, targeting the deregulated JAK/STAT pathway could be a promising therapy for patients with NKTCLs.

SIGNIFICANCE

Gene mutations causing NKTCL have not been fully identified. Through exome sequencing, we identified activating mutations of JAK3 that may play a significant role in the pathogenesis of NKTCLs. Our findings have important implications for the management of patients with NKTCLs.

Clinical pharmacy services and research for lymphoma patients at a cancer center

At the National Cancer Centre Singapore, which is currently the largest ambulatory cancer centre in Singapore, clinical pharmacists have taken upon responsibilities to provide direct pharmaceutical care in the center’s lymphoma team since 2006. Given the complexity and intricacies of lymphoma treatments, clinical pharmacists are often positioned to ensure supportive care is optimized among these patients. Besides management of chemotherapy-related and supportive care issues, clinical pharmacists play a pivotal role in guiding cost-effective and safe prescribing. In collaboration with the medical team, they are also involved in conducting practice research in order to optimize the delivery of pharmaceutical care. In this report, the dedicated services and research activities conducted by clinical pharmacists of a lymphoma team will be discussed.

Management of tumor lysis syndrome with a single fixed dose of rasburicase in Asian lymphoma patients: a case series and literature review

AIM

Recently, a number of studies have demonstrated the effectiveness of a single reduced dose of rasburicase for the management of tumor lysis syndrome (TLS) in adults. Whether Asian lymphoma patients similarly respond to a single dose of rasburicase is currently unknown. We aim to assess the efficacy of a single dose rasburicase in preventing TLS in Asian lymphoma patients.

METHODS

This was a single-center case series of adult lymphoma patients at high risk of TLS who received a single fixed dose of rasburicase. Patients had to have their uric acid, serum creatinine, lactate dehydrogenase and electrolytes monitored for at least 24-48 h post-administration.

RESULTS

Eleven patients were identified. Majority were Chinese (91%), male (64%) and with a median age of 61 years (range 41-84). All had at least two risk factors for developing TLS. Ten patients received a 6-mg dose and one received 4.5 mg. Prior to rasburicase administration, the mean uric acid level was 835 µmol/L (range 318-1237 µmol/L) and the level 24-h post-administration was 186 µmol/L (range 30-653 µmol/L) (P < 0.001). Eight patients (73%) experienced an improvement of renal function 72-h post-rasburicase. Normalization of serum electrolytes was achieved within 96 h.

CONCLUSION

Among Asian lymphoma patients who manifested at least two risk factors for developing TLS, a single fixed dose of rasburicase at 6 mg is deemed to be effective for rapidly lowering uric acid levels as well as sustaining reduced levels for up to 72 h.

Effect of sunlight exposure on survival in patients with lymphoma: Results from the prospective Singapore Lymphoma Study

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Background: Recently, several studies evaluating the effect of ultraviolet light exposure on the risk of developing lymphoma have yielded conflicting results, in part due to seasonal and latitude variation. Further, most of these studies also lack long term follow up and could not systemically address the influence of sunlight exposure on survival. In this prospective, epidemiological study, we explored the relationship between past sunlight exposure and survival in lymphoma patients in tropical Singapore, where sunlight exposure is constant throughout the year. Methods: Singapore Lymphoma Study was established in 2005. A total of 384 patients with histologically confirmed lymphoma were followed from date of diagnosis through November 2011. Interviewers were trained to conduct in-person interviews to collect detailed information, including every occupational period that lasted at least 1 year and number of hours worked outdoor from 9am to 5pm using a structured questionnaire. Descriptive, multivariate and survival analysis (Kaplan Meier; age, gender, race and education level adjusted) were performed. Results: Among all lymphoma subtypes, the most prevalent was diffuse large B cell lymphoma, 47.7%, followed by Hodgkin lymphoma, 14.6%, follicular lymphoma, 12.2% and T cell lymphoma, 6.5%. 97.1% had black or brown eye color and 49.6% had fair skin. Overall survival of lymphoma and NHL subtype decreased significantly with increasing lifetime occupational hours (ptrend=0.01 and 0.03). Chinese was associated with longer survival with increasing daily sunlight exposure during childhood and adolescent years, whether at school or outdoor leisure (ptrend=0.04) and there were no evidence for non-Chinese (Malays or Indians). Patients with lighter eye color results in shorter survival (HR=2.91, 95% CI: 1.15-7.34, p=0.02). Conclusions: We found leisure sunlight exposure during childhood and adolescent years to be beneficial to the survival of Chinese lymphoma patients and increasing lifetime cumulative occupational exposure is associated with increasing risk of death. This data contributes to the growing research on the effects of sunlight exposure on lymphoma patients.

Association of tumor-associated macrophages of M2 subtype with outcome in follicular lymphoma

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Background: Current methods used to prognosticate patients with follicular lymphoma (FL) include the Follicular Lymphoma International Prognostic Index (FLIPI) and tumor grade. However, they do not provide information on the biological and molecular features of FL. Recent data suggest that high tumor-associated macrophages (TAM) content may be an adverse prognostic factor in FL. However, TAM consists of two main subtypes, M1 and M2, with the former related to pro-inflammatory properties while the latter, anti-inflammatory functions. Currently, the prognostic impact of each individual subtype has not been elucidated and this may be more important than looking at TAM alone. Methods: Tumor specimens of 98 patients with FL diagnosed between 2005 and 2009 were investigated using immunohistochemistry and fluorescence in-situ hybridization (FISH) using break-apart FISH probes targeting BCL2, BCL6, MYC and IgH genes. Tumor specimens expressing a higher proportion of CD68+/CD163- in one high power field were defined as M1 subtype and those that expressed a greater proportion of CD68+/CD163+ were denoted as M2 subtype. Results: Amongst the 98 patients, 60 (61%) were of the M2 subtype, 59% presented with advanced disease, 47% were grade 3 and the median age was 59 years (21 – 88 years). Baseline characteristics including grade, stage and recurrent translocations did not significantly differ between the M1 and M2 groups. Similarly, there was also no difference in terms of treatment received (both Rituximab and chemotherapy) between the two groups. Despite these similarities, with a median follow-up of 3.2 years, the 3-year overall survival (OS) was significantly different (M1, 100% vs M2, 85%; p < 0.01). All 11 patients who died were of the M2 subtype (p=0.009). Conclusions: Our findings show that despite similar patient characteristics and treatment, there was, however, a statistically significant difference in OS, with the M2 subtype demonstrating an inferior outcome. The M2 TAM subtype rather than TAM alone may be a more important prognostic marker in FL, which could possibly be explained by its known biological anti-inflammatory function.

Geriatric high-grade soft tissue sarcoma (G-HG STS): An analysis of 116 patients (pts) evaluating prognostic factors and clinical outcomes stratified by histology

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Background: STS in geriatric pts is not well studied. We evaluated prognostic factors and clinical outcomes in elderly pts with HG STS. Methods: Single centre retrospective study. G-HG STS pts defined as age > 65 yrs seen in our centre from 2002 - 2011 with complete medical records were identified. Charlson age-comorbidity score was assessed for each pt. Results: 116 pts from 4 most common HG STS histo-types representing 69% of pts in the geriatric STS cohort were analysed; leiomyosarcoma (LMS, 14%), non well-differentiated liposarcoma (nWD-LPS, 9%), angiosarcoma (AS, 30%), and undifferentiated pleomorphic sarcoma (UPS, 47%). Median age was 72 yrs, 81% presented with localised disease; of 78% of these localised pts who had curative surgery, 49% received adjuvant therapy, of whom 92% had radiotherapy (RT) only. AS arises more commonly from the head/neck region (p<0.001) and fewer receive curative surgery (p=0.006). In 43 pts who had metastases either at diagnosis or relapse, 33% received first-line palliative chemotherapy with a response rate of 27% in evaluable pts. At a median follow-up of 15.8 mths, overall survival (OS) for the entire cohort was 25.1 mths, 30.5 vs 3.9 mths in pts presenting with localised vs metastatic disease respectively (p<0.0001). In pts who had curative surgery for localised disease, overall relapse-free survival (RFS) was 17.7mths; 26.8 mths vs 16.0 mths vs 7.3 mths vs 12.5 mths in LMS, nWD-LPS, AS and UPS respectively. In univariate analysis, adjuvant RT, non-head/neck primary and sarcoma subtype were associated with improved RFS. In multivariate analysis, adjuvant RT (p<0.001), sarcoma subtypes AS (p=0.011) and UPS (0.012) vs LMS remained significant. In pts with metastatic HG STS either at diagnosis or relapse, overall median OS was 5.9 mths; 5.9 mths (LMS), 30.5 mths (nWD-LPS), 6.4 mths (AS) and 4.3 mths (UPS). In univariate analysis, presence of bone metastases was significantly associated with inferior OS (p=0.0029). Charlson score did not correlate with RFS or OS. Conclusions: Prognosis of G-HG STS appears poor particularly in AS and UPS. Adjuvant RT improves outcomes in this group of pts and should not be omitted based on age alone.

AIDS-related lymphoma (ARL) in Asians in the era of HAART and rituximab

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Background: We described EBV & HHV8 co-infection rates, histology subtypes (particularly T-cell), prognosticators and outcomes of Asian ARL and compared them to Western series. Methods: We studied clinicopathologic features of 46 HAART-era ARL diagnosed from 1998-2011 in an Asian Tertiary Cancer Centre. To study HIV effect on survival, we applied multivariate analysis to HIV-DLBCL matched against 453 de novo DLBCL from 2000-2008. Results: The 46 patients’ characteristics are presented in the table below. Of note, germinal centre B-cell (GCB) subtype predominated in HIV-DLBCL with evaluable tissue. In multivariate analysis of HIV-DLBCL and matched de novo DLBCL, HIV status did not predict survival (HR1.33, p=0.63); CR was the only significant prognosticator (HR0.30, p=0.048). Conclusions: 1. EBV+ rates appeared to surpass prior Western ARL series. Although concomitant EBV infection appeared to correlate with inferior survival (HR34.5), it was not statistically significant. 2. Alb<30 (p=0.02) & Hb<10 (p=0.003) significantly predicted worse OS, but not CD4 or concurrent HIV&ARL diagnosis. 3. In this predominantly EPOCH-treated population, BL (HR 2.27) non-significantly trended to worse OS than DLBCL. 4. T-cell ARL (2/46, 4%) was rarer than the expected Asian de novo rate. 5. In multivariate analysis, HIV-DLBCL OS was similar to matched de novo DLBCL, suggesting they should be similarly treated with curative intent. CR rates and 5yr OS were comparable to de novo DLBCL. [Table: see text]

Non-bacterial infections in Asian patients treated with alemtuzumab: a retrospective study of the Asian Lymphoma Study Group

This retrospective study concerns non-bacterial infections in Asian patients receiving alemtuzumab. The clinical data of 182 patients treated with alemtuzumab alone or alemtuzumab-containing chemotherapy between the years 2003 and 2009 was collected from six Asian countries. Alemtuzumab was used in the setting of frontline (n =48) or salvage (n =90) treatment, and as a part of the conditioning regimen for allogeneic stem cell transplant (n =44). Reactivation of cytomegalovirus (66/182) and varicella zoster virus (25/182), and fungal infection (31/182) including invasive pulmonary aspergillosis, were the most common infectious complications in this retrospective analysis. Thus, we recommend routine prophylaxis with valganciclovir and itraconazole, especially when alemtuzumab is used in the conditioning regimen for allogeneic stem cell transplant. Pneumocystis jirovecii pneumonia (PJP) was found in four patients (3%, 4/122) receiving alemtuzumab as conditioning for stem cell transplant or salvage treatment. Three cases of hepatitis B virus reactivation were found in antigen-negative patients, and 16 cases of tuberculosis were observed. Infection is the major complication of alemtuzumab therapy, and these infectious complications are potentially severe and life-threatening. Based on our retrospective analysis, we have constructed a guideline for antimicrobial prophylaxis in Asian patients receiving alemtuzumab therapy.