Normal Sequence and Activity but Reduced Levels of DNA-Pkcs in Human Lymphoblastic Cells Implicate Impaired Protein Stability with Radiosensitive Phenotype.

Background: Non-homologous end joining (NHEJ) is the main repair pathway for DNA double strand breaks (DSBs) induced by ionizing radiation in mammalian cells. Subsets of cancer patients are hypersensitive to radiotherapy after standard doses. We sought to determine the radiosensitivity of human lymphoblastic cells (LB0005) for the abnormality in NHEJ components.

High incidence of nasopharyngeal cancer: similarity for 60% of mitochondrial DNA signatures between the Bidayuhs of Borneo and the Bai-yue of Southern China.

Populations in Southern China (Bai-yue) and Borneo (Bidayuh) with high incidence of nasopharyngeal cancer(NPC) share similar mitochondrial DNA signatures, supporting the hypothesis that these two populations may share the same genetic predisposition for NPC, which may have first appeared in a common ancestral reference population before the sea levels rose after the last ice age.

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

Unlabelled: 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.

Sun exposure and risk of lymphoid neoplasms in Singapore.

Background: Epidemiologic studies have reported an inverse association between sun exposure and non-Hodgkin lymphoma (NHL), but these have been almost exclusively conducted in Western populations residing in temperate locations. We evaluated the association between personal outdoor sun exposure and risk of malignant lymphomas in Singapore.

Methods: A hospital-based case-control study of 541 incident cases of lymphoid neoplasms and 830 controls were recruited during 2004-2008.

Is nasopharyngeal cancer really a "Cantonese cancer"?

Nasopharyngeal cancer (NPC) is endemic in Southern China, with Guandong province and Hong Kong reporting some of the highest incidences in the world. The journal Science has called it a "Cantonese cancer". We propose that in fact NPC is a cancer that originated in the Bai Yue ("proto Tai Kadai" or "proto Austronesian" or "proto Zhuang") peoples and was transmitted to the Han Chinese in southern China through intermarriage.

Weak expression of cyclooxygenase-2 is associated with poorer outcome in endemic nasopharyngeal carcinoma: analysis of data from randomized trial between radiation alone versus concurrent chemo-radiation (SQNP-01).

Background: Over-expression of cyclooxygenase-2 (COX-2) enzyme has been reported in nasopharyngeal carcinoma (NPC). However, the prognostic significance of this has yet to be conclusively determined. Thus, from our randomized trial of radiation versus concurrent chemoradiation in endemic NPC, we analyzed a cohort of tumour samples collected from participants from one referral hospital.

Presence of a high-grade component in gastric mucosa-associated lymphoid tissue (MALT) lymphoma is not associated with an adverse prognosis.

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B cell lymphoma (DLBCL) show a spectrum of disease characterized by varying proportions of low-grade and high-grade components. While the natural history and optimum treatment for low-grade gastric MALT lymphoma and DLBCL is well established, the prognosis and optimal treatment of patients with both low- and high-grade components is not well established. The purpose of our study was to evaluate the clinical characteristics, survival outcomes, and prognostic factors of patients with gastric MALT lymphoma and gastric DLBCL.

Increased but error-prone nonhomologous end joining in immortalized lymphoblastoid cell extracts from adult cancer patients with late radionecrosis.

Purpose: To study nonhomologous end joining in extracts of two lymphoblastoid cell lines derived from patients with late radionecrosis after radiotherapy. Both cell lines were previously shown to exhibit impaired rejoining of DNA double-strand breaks in a pulse-field gel electrophoresis assay.

Methods And Materials: We used a cell-free system and quantitative real-time polymerase chain reaction, as well as sequencing analysis of end joining products.

An Epstein-Barr virus positive natural killer lymphoma xenograft derived for drug testing.

Natural killer (NK) lymphomas occurring more frequently in the Far East and South America respond poorly to anthracycline-based regimens. Here we report an in vivo NK lymphoma xenograft (NK-S1) derived from the testicular metastasis of a patient with an extranodal NK lymphoma (nasal type). The NK-S1 xenograft, established in severe combined immune deficient (SCID) mice retained the same imunophenotypic features as the original tumor.

The relationship of hepatitis B virus infection and non-Hodgkin's lymphoma and its impact on clinical characteristics and prognosis.

Aim Of The Study: This study aims to evaluate the association between hepatitis B virus (HBV) and lymphoma and to characterize HBV-related lymphomas. The efficacy of prophylactic lamivudine on HBV reactivation was also evaluated.

Methods: We compared the prevalence rate of HBV infection in 556 patients with lymphoma seen over a 4-yr period with that in a group of 4698 Singapore residents aged 18-69 who participated in the National Health Survey.

A novel approach to brachytherapy in hepatocellular carcinoma using a phosphorous32 (32P) brachytherapy delivery device--a first-in-man study.

Purpose: While potentially very useful, percutaneously delivered brachytherapy of inoperable intra-abdominal solid tumors faces significant technical challenges. This first-in-man study is designed to determine the safety profile and therapeutic efficacy of a novel phosphorous (32P) brachytherapy device (BrachySil) in patients with unresectable hepatocellular carcinoma.

Methods And Materials: Patients received single percutaneous and transperitoneal implantations of BrachySil under local anesthesia directly into liver tumors under ultrasound or computed tomographic guidance, at an activity level of 4 MBq/cc of tumor.

Complete tumor response following intratumoral 32P BioSilicon on human hepatocellular and pancreatic carcinoma xenografts in nude mice.

Purpose: 32P BioSilicon is a new, implantable, radiological medical device that comprises particles of highly pure silicon encapsulating 32phosphorus (32P) for the treatment of unresectable solid tumors. Prior to administration, the device particles are suspended in a formulant which provides an even suspension of the intended dose for implantation. The primary objective of this animal trial study was to investigate the effects of intratumoral injection of 32)P BioSilicon on human hepatocellular (HepG2) and pancreatic carcinoma (2119) xenografts implanted in nude mice (BALB/c).

Outcome of patients with nasal natural killer (NK)/T-cell lymphoma treated with radiotherapy, with or without chemotherapy.

Background: This study reviews the outcome of patients with nasal natural killer (NK)/T-cell lymphoma treated at the Therapeutic Radiology Department, National Cancer Centre, Singapore, from 1997 to 2003.

Methods: Twenty-one consecutive patients treated with radiotherapy, with or without chemotherapy, were retrospectively reviewed.

Results: The median age was 44 years (range, 27-86 years).

Randomized trial of radiotherapy versus concurrent chemoradiotherapy followed by adjuvant chemotherapy in patients with American Joint Committee on Cancer/International Union against cancer stage III and IV nasopharyngeal cancer of the endemic variety.

Purpose: The Intergroup 00-99 Trial for nasopharyngeal cancer (NPC) showed a benefit of adding chemotherapy to radiotherapy. However, there were controversies regarding the applicability of the results to patients in endemic regions. This study aims to confirm the findings of the 00-99 Trial and its applicability to patients with endemic NPC.

Nasal-type extranodal natural killer/T-cell lymphomas: a clinicopathologic and genotypic study of 42 cases in Singapore.

We studied the clinicopathologic features of 42 cases of nasal-type extranodal natural killer (NK)/T-cell lymphoma in Singapore and compared our findings with other series reported in the Asian and Western populations. A panel of immunohistochemical stains, which included CD2, CD3, CD4, CD8, CD56, T-cell intracellular Antigen-1 and granzyme B, and in situ hybridization for Epstein-Barr virus encoded RNA (EBER) were performed. Polymerase chain reaction for T-cell receptor-gamma gene rearrangement using both gel and capillary electrophoresis were evaluated to determine the proportion of tumors which are of true T-cell lineage.

Reduced DNA-dependent protein kinase activity in two cell lines derived from adult cancer patients with late radionecrosis.

Epstein-Barr virus-immortalized lymphoblastoid cell lines were derived from five patients with late radionecrosis. Two of these cell lines exhibited postradiation viability levels intermediate between normal cell lines and that from an individual with ataxia telangiectasia. Compared with controls, these two cell lines exhibited impaired ability to rejoin DNA double-strand breaks on pulsed-field gel electrophoresis and 6-10-fold reduced DNA-dependent protein kinase (DNA-PK) activity in vitro in cell-free extracts.

Primary nasal lymphoma, NK/T-cell type: report of two cases with similar presentation but different outcome.

Two cases of natural killer (NK)/T-cell primary nasal lymphoma with similar clinical presentations are reported, for comparison and contrast, to highlight the clinical issues and challenges posed by this unusual disease, its aggressiveness being matched only by its rarity. Presenting as a lesion in the nasal cavity with histological features of malignant lymphoma, primary nasal lymphoma is an uncommon extranodal lymphoma, which poses problems in both diagnosis and management. In people of oriental descent, the common cell subtype is NK/T-cell.