An Intrinsic Thymic Epithelial Abnormality Is Responsible for the Spontaneous Development of Predominantly Lymphocytic Thymomas in BUF/Mna Rats

The nature of tumorigenesis of predominantly lymphocytic thymoma was examined using an animal model. Rats of the inbred BUF/Mna strain were found spontaneously to develop predominantly lymphocytic thymomas, histologically indistinguishable from their human counterparts, at an incidence of virtually 100%. Thymic rudiments of BUF/Mna rats grafted 17 months previously under the renal capsule of young athymic ACI/NMs- rnu/rnu rats also gave rise to similar lesions. The lymphocytes in the thymomas expressed T-cell antigens (rat Lyt-1 and Lyt-2.3), as in the normal case, and ACI rat specific antigen. When BUF/Mna rats of thymoma age were irradiated with a lethal dose of 12 Gy and then received a single injection of bone marrow cells (8 × 10⁷) from BALB/c- nu/nu mice, thymomas were re-formed three weeks later (in 2 of 5 rats) with the replacement lymphocytes expressing mouse Thy-1.2 antigen. These results indicate that an intrinsic thymic epithelial abnormality is responsible for the development of predominantly lymphocytic thymomas in BUF/Mna rats.     

Nodular Development of Spontaneous Epithelial Thymoma in (ACI/NMs × BUF/Mna)F1 Rats

The BUF/Mna strain is a high thymoma line of rats, and virtually all rats develop overt thymomas by the age of 40 weeks. To reveal the early morphologic changes in this thymomagenesis, thymuses and thyraomas were studied in (ACI/NMs × BUF/Mna)Fl (ABF1) rats, which inherit a thymoma susceptibility gene ( Tsr-1 ) from the BUF/Mna strain. At 50 weeks of age, 18% of ABF1 rats had developed medium to large thymomas, 54% had just began to develop multiple, small round nodules in their involuted thymuses, and the remaining 29% had involuted thymus only. The nodules were, microscopically, composed of cortex-like tissues with a starry-sky pattern, showing a quite similar structure to that of the large macroscopic thymomas of predominantly lymphocytic type seen in 104-week-old ABF1 or BUF-Mna rats. Thus, the nodule was actually a small thymoma. In fact, their epithelial cells often had larger atypical nuclei than those in the adjacent involuted thymus cortex. At 104 weeks of age, the incidences of the medium to large thymomas and the small thymoma nodules in ABF1 rats were 64 and 19%, respectively. These results suggest that the thymoma of ABF1 rats occurs initially as multiple small nodules which develop further into medium to large overt thymomas as a result of growth and fusion.     

Establishment of Transplantable Tumor Lines and in vitro Cell Lines of Malignant Thymoma Developed in a BUF/Mna Rat

A spontaneous malignant thymoma was found in an 18-month-old female BUF/Mna rat and serially transplanted subcutaneously in both syngeneic BUF/Mna rats (designated as MTH-R) and KSN nude mice (MTH-NM) for more than 5 years. Both tumors shared the histological appearance of sarcomatoid carcinoma as seen in the original tumor. However, MTH-NM grew faster than MTH-in the respective hosts. The MTH-NM grew in both KSN-nude mice and BUF/Mna- rnu/rnu rats but not in BUF/Mna rats the host of the original tumor. Three continuous tissue culture cell lines (MTHC-1, MTHC-2 and MTHC-3) were established from the MTH-NM tumors at the 2nd, 15th and 17th transplantation generations, respectively. The MTH-NM tumors and latter two tissue culture cell lines carried one or more mouse chromosomes, probably acquired by cell fusion with mouse cells during passages in vivo. The presence of the mouse chromosomes was confirmed by the presence of mouse DNA and of antibodies to the MTHC-2 and MTHC-3 cells in the sera of BUF/Mna rats transplanted with MTH-NM.     

Genetic Regulation of Development of Thymic Lymphomas Induced by N-Propyl-N-nitrosourea in the Rat

To clarify the linkage between Hbb and Tls-1 (thymic lymphoma susceptible-1) loci and to investigate other loci concerned in thymic lymphomagenesis, the BUF/Mna rat, which is highly sensitive to the lymphomagenic activity of N -propyl- N -nitrosourea (PNU), the WKY/NCrj rat, reported to be resistant, and their cross offspring were subjected to genetic analysis. F₁ hybrid and backcross generations were raised from the 2 strains, and 6 genetic markers including Hbb were analyzed in individuals of the backcross generation. However, no linkage between Hbb and Tls-1 loci could be demonstrated since WKY rats also developed a high incidence of thymic lymphomas in response to PNU. Nevertheless, thymic lymphomas developed more rapidly and reached a larger size in the BUF rats. F₁ rats expressed a rather rapid and large tumor growth phenotype, while the [(WKY × BUF) × WKY] backcross generation consisted of rats with either rapidly growing or slowly growing tumors. It was thus concluded that rapid development of thymic lymphomas is determined by a gene, provisionally designated Tls-3 . Analysis of the relationship between 6 genetic markers and development of thymic lymphoma in the backcross generation demonstrated that the Tls-3 locus is loosely linked to the Gc locus, suggesting a possible location on rat chromosome 14. Tls-3 may not be identical with Tls-1 and other genes known to be relevant to thymic tumors, but its relationship with Tls-2 remains obscure.     

Expression of p21waf-1/cip-1 Is Significantly Induced in the Livers of LEC Rats with Chronic Liver Injury

It is reported that hepatocytes isolated from LEC rats with chronic liver injury show reduced growth activity in primary culture. To elucidate the molecular basis of this phenomenon, we examined expression of p21^waf-1/cip-1 and p27, cyclin-dependent kinase inhibitors, by northern blot analysis. The expression of p21^waf-1/cip-1 in the LEC rat liver was 3-fold higher than that of age-matched SD rat liver, while there was no significant difference in p27 expression level. Western blot analysis also revealed a significant increase in p2l^waf-1/cip-1 in the nuclear matrix fraction of the LEC rat liver. Immunohisto-chemically, p21^waf-1/cip-1 was detected in the nuclei of normal LEC rat hepatocytes, but not in those of hepatocellular carcinoma cells, suggesting selective growth of neoplastic hepatocytes.     

Genetic Variations in Carcinogen Metabolizing Genes Associated with Oral Cancer in Pakistani Population

Background: Xenobiotics are metabolized by either phase I enzymes like CYP1A1 or phase II enzymes likeGSTs. Polymorphisms in the encoding genes (CYP1A1, GSTM1, GSTT1 and GSTP1) potentially may thererforecontribute towards risk association for oral cancer. Methodology: These genes were investigated via a casecontrol study consisting of 228 oral cancer patients and 150 cancer free normal individuals as controls. DNA wasextracted from WBCs for genotyping. Polymerase chain reaction–single stranded conformational polymorphism(SSCP) was used for screening CYP1A1 and GSTP1 genes mutations. Deletion of GSTM1 and GSTT1 genes wereanalyzed by multiplex PCR. Results: Two novel mutations were found in this study in relation to oral cancer. Asubstitution mutation of A2842 with C resulting in missense tyrosine to serine formation along with a frameshiftmutation due to insertion of thymidine at nucleotide 2842 resulting in 495 nucleotide sequence to alter was foundin oral cancer patients. GSTM1 and GSTT1 deletion polymorphism was found in significantly higher number ofindividuals (OR=2.08, CI 1.05-4.2; OR=1.5, CI 0.9-2.4 respectively) compared to controls. 10 patients had deletionof both GSTM1 and GSTT1 genes. GSTP1 gene was also found to have novel substitution mutations of A2848 toT and G2849 to A in exon 7 resulting in leucine to leucine and alanine to threonine formation respectively. Twointronic deletions of cytosine at positions 1074 and 1466 was found in intron 3 and 4 in patients and no controlhad these exonic or intronic variants in GSTP1 gene. Conclusion: These results suggest that accumulation ofgenetic changes in CYP1A1, GSTM1, GSTT1 and GSTP1 genes are associated with increased risk of oral cancer.     

Carcinogenicity of Captafol in F344/DuCrj Rats

Captafol was administered at dietary levels of 0 (control), 750 and 1,500 parts per million (ppm) to groups of 50 male and 50 female F344/DuCrj rats for 104 weeks, and then all animals were maintained without captafol for a further 8 weeks, and killed in week 113. Renal cell carcinoma was found in eight of 50 male rats treated with 1,500 ppm and in one of 50 male rats treated with 750 ppm of captafol. The incidences of renal adenomas, including micro-adenomas, and basophilic altered cell tubules were significantly higher in both sexes treated with captafol than in controls, and the increases were apparently dose-dependent except that of adenomas in females. The incidences of neoplastic and preneoplastic lesions of the kidney in captafol-treated animals were higher in males than in females. Captafol also induced hepatocellular carcinomas in four of 50 female rats in the 1,500 ppm group. The incidences of hyperplastic (neoplastic) nodules and foci of cellular alterations in the liver were also significantly increased in both sexes treated with captafol, the increases being dose-dependent. In conclusion, captafol induced renal cell carcinomas in male rats and hepatocellular carcinomas in female rats.     

1-氯甲基杂氮硅三环对大鼠致畸毒性试验

背景与目的： 观察1-氯甲基杂氮硅三环对大鼠的致畸毒性。 材料与方法： 将SD孕鼠随机分为1-氯甲基杂氮硅三环高、中、低3个不同剂量(10.29、32.54、102.89 mg/kg)的给药组,以及溶剂对照组(3％淀粉糊)和敌枯双阳性对照组(1 mg/kg),共5组。大鼠妊娠第6～15 d每天灌胃染毒1次,妊娠第20 d处死,检查各项指标。 结果： 1-氯甲基杂氮硅三环中、高剂量组胎仔骨骼畸形率较溶剂对照组增加(P<0.05或P<0.01),主要表现为胸骨骨化不全、缺失和形状异常等,其最小致畸量为32.54 mg/kg;各剂量组孕鼠的体重和胚胎毒性与阴性对照组比较差异无统计学意义(P>0.05);各剂量组胎仔的生长指标、外观和内脏均未见异常。 结论： 在本实验条件下, 1-氯甲基杂氮硅三环一定剂量下对SD大鼠有致畸毒性。     

Genetic Polymorphisms of Fas/FasL Promoter Associated with Hepatitis C cirrhosis and HCC

Aim: The present study was performed to determine any associations of genetic polymorphisms of Fas/FasL promoter regions, at Fas670 and Fas1377 and FasL844, with hepatitis C cirrhosis and HCC, with a focus on severity of disease. Methods: Totals of 120 patients with cirrhosis and 101 with hepatocellular carcinoma (HCC) were enrolled. All had chronic HCV infection as indicated by positive anti-HCV antibodies and positive HCV RNA on real time PCR. One hundred healthy control subjects were also included in the study. Patients were subjected to full clinical, radiological and histopathological examinations. In addition to routine laboratory tests for liver function tests, Fas670 and Fas1377 and FasL844 genetic polymorphisms of Fas/FasL promoter regions were assessed by RFLP-PCR (restriction fragment length polymorphism with polymerase chain reaction). Results: Significant higher levels of the AG genotype in Fas670 and Fas1773 were observed in patients with cirrhosis and HCC (P=0.0001) as compared to control subjects. In addition, the CC genotype in FASL844 was also more common in patients (P=0.01). Furtehrmore, there was a significant association of substitution of A by G alleles in Fas670 and Fas1773 with advanced BCA staging (P=0.02, P=0.0001 respectively) and larger tumor size >5cm (P=0.01, P=0.0001 respectively) and in Fas670 with advanced pathological grading (P=0.0001). Moreover the CC genotype of FASL844 was significantly linked with advanced BCA, large tumor size >5cm and advanced pathological grading (P=0.0001). Conclusion: The findings of the present study highlight associations of genetic polymorphisms of promoter regions in Fas and Fas L with cirrhosis and HCC associated with chronic HCV. Support was also obtained for the conclusion that single nucleotide polymorphisms of the Fas/ FasL system impact on clinical and histopathological grading of HCCs. Further large scale studies are recommended for confirmation.     

Specific Chromosomal Abnormalities in Patients with Acute Nonlymphocytic Leukemia from the Islamic Republic of Iran

Cytogenetic analysis performed at diagnosis is considered to be the most valuable prognostic factor in acute nonlymphocyticleukemia (ANLL), a very heterogeneous disease. Little data exist in Iran regarding the cytogeneticcharacteristics of ANLL . Therefore, cytogenetic investigations were performed for 58 patients with various subtypesof ANLL with unstimulated short term culture and high resolution cell synchronization techniques. Among the 58evaluated patients, 45 (77.5%) showed clonal karyotypic abnormalities and the percentages of the abnormal cellswere recorded within the range of 30%-100%. Some 14 were classified as M1, 20 as M2, 19 as M3 , 3 as M4, 1 as M5and 1 as M6. The most common chromosome rearrangements were t(15;17), t( 8;21) and t(9;22). Trisomy ofchromosome 8 (+8) was the most frequent numerical alteration in 3 patients with M1, M2 and M6. The incidence ofother chromosomal defects, including -10, DMCs , -19 , 5q- , dicentric(dic), chromatid breaks, and markerchromosomes was relatively high. Similarities and dissimilarities of our study with others may be due to the role ofgenetic sensitivities as well as uneven geographic distribution in the pathogenesis of ANLL. Further prospectivestudies are warranted to precisely elucidate ethnic differences in the pathogenesis of this disease in differentpopulations.     

1p/19q chromosome deletions in metastatic oligodendroglioma

Extracranial metastasis of primary brain tumors is a rare phenomenon. Of the few cases reported of metastatic oligodendroglioma, only two have evaluated genetic alterations, specifically deletions of chromosomes 1p and 19q. Herein, we report two additional patients with metastatic anaplastic oligodendroglioma to bone, both followed until death. All available pathology specimens were reviewed and genetic analysis was performed in one of the cases. Although the bone metastasis was non-informative, the primary intracranial tumor revealed codeletions of the 1p and 19q chromosomal arms, commonly recognized as the genetically favorable profile of oligodendrogliomas. Both patients died of complications related to their systemic disease and did not have any radiologic evidence of intracranial progression at the time of their last MRI studies. Along with the reported literature, our data suggest that despite their generally favorable behavioral profiles, oligodendroglial tumors with 1p/19q deletions may be more prone to metastasis as they progress. Genetic analysis serves a valuable ancillary role in the diagnostic workup of such cases.     

Lack of Chronic Oral Toxicity of Chemopreventive Bovine Lactoferrin in F344/DuCrj Rats

Studies were undertaken to determine whether bovine lactoferrin (bLF) and related compounds, shown to prevent carcinogenesis in the colon and other organs in rats, have any toxic effects in long-term feeding studies. In experiment I, male F344/DuCrj rats received a basal diet containing 0.2% bLF for 40 weeks. No adverse findings were noted, furthermore, serum triglyceride level was significantly decreased to 72% of the control level, suggesting preventive effects against the metabolic syndrome. In experiment II, male and female F344/DuCrj rats were fed a basal diet containing 0.02, 0.2, 2.0 and 5.0% bLF, 2.0% bLF hydrolysate (bLF-H) or 0.1% lactoferricin (LFcin), a peptide derived from bLF, for 60 weeks in males and 65 weeks in females. No toxicological effects, including carcinogenicity, were evident in either sex. The results of the studies provide subjective support for safety of clinical studies of bLF for supplement use.     

SNP rs9387478 at ROS1-DCBLD1 Locus is Significantly Associated with Lung Cancer Risk and Poor Survival in Indian Population

Objective: Receptor tyrosine kinases (RTK) are relevant therapeutic targets in the treatment of lung cancer. Germline susceptibility variants that influence these RTKs may provide new insights into their regulation.  rs9387478 is located in the genomic interval between two RTK-genes ROS1/DCBLD1, of which ROS1 alterations are implicated in lung carcinogenesis and treatment response while the latter remains poorly understood. Materials and methods: Venous blood was drawn from 100 control and 231 case subjects. Genotype was scored by restriction fragment length polymorphism (RFLP), PCR amplification followed by HindIII digestion. Logistic regression was applied to compare the association between variables. Survival curve was plotted to draw a correlation between the genotype and overall survival. Also, eQTL and chromatin state changes were analyzed and correlated with the survival of patients using available datasets. Results: In our population smoking correlated significantly with lung cancer [OR= 2.607] with the presence of the minor allele ‘A’ enhancing the nicotine dependence [CA (OR=3.23)]. Individuals with homozygous risk allele ‘A’ had a higher chance of developing lung cancer [OR=2.65] than individuals with CA/CC implying a recessive model of association. Patients with CC/CA genotype had better overall survival than patients with AA genotype [161 days/142 days vs 54 days, p=0.005]. The homozygous risk allele was significantly associated with increased DCBLD1 and ROS1 expression in lung cancer, with enriched active histone marks due to the polymorphism. Interestingly, increased DCBLD1 expression was associated with poor outcomes in lung cancer. Conclusion: Overall, our study provides strong evidence that rs9387478 is significantly associated with both nicotine dependence and lung cancer in our North Indian cohort. The association of the SNP with prognostic genes, DCBLD1 and ROS1 make rs9387478 a promising prognostic marker in the North Indian population. The results obtained are significant, however, the study needs to be performed in a larger sample size.     

MUC1及同种型MUC1/Y基因mRNA在膀胱癌中的表达及临床意义

目的：探讨肿瘤相关抗原MUC1及同种型MUCI／Y粘蛋白基因在膀胱癌中mRNA的表达及其临床意义．方法：22例膀胱癌的组织样本（实验组）和10例正常膀胱组织样本（对照组）中提取总RNA，采用逆转录聚合酶链反应（RT-PCR）技术，检测两组样本中MUC1及同种型MUC1／Y粘蛋白基因mRNA表达水平，结果：膀胱癌组织的MUC1mRNA水平较正常膀胱组织显著增高（P〈0．01）；Ⅲ-Ⅳ期膀胱癌组织的MUC1／YmRNA水平较Ⅰ-Ⅱ期膀胱癌组织显著增高（P〈0．01）。结论：MUC1及同种型MUCI／Y粘蛋白基因mRNA表达水平与膀胱癌有关，对膀胱癌的诊断和治疗有临床意义一，     

Sequencing of Chromosomal Locus 6q25.1 Revealed Two Significant SNPs rs2046210 and rs2046211 Associated with Breast Cancer: A Case-Control Study in Egyptian Women

Background: Breast cancer (BC) is one of the major health problems affecting females in Egypt. Certain chromosomal loci abnormalities were proved to be associated with BC in different populations. One of them is chromosomal locus 6q25.1, that affects estrogen receptor gene (ESR) which controls ER receptor expression. Therefore, the aim of this study was to investigate locus 6q25.1 among group of Egyptian female BC patients and compare the results to healthy matched age controls. Methods: Formalin fixed paraffin embedded (FFPE) samples of sixty newly diagnosed BC patients were sequenced for locus 6q25.1 using genetic analyzer with capillary electrophoresis (3500 GA). The identified single nucleotide polymorphisms (SNPs) were compared to blood samples of forty controls. Realtime PCR using TaqMan probes was used for validation. Results: Two SNPs rs2046210 and rs2046211 were significantly associated with BC. Frequency of rs2046210-A minor allele was 30% in controls, while the frequency of rs2046211-G minor allele was 15%. Rs2046210-A allele was associated with increased risk of BC (P=0.0001), while rs2046211-G allele was associated with reduced risk of BC (P=0.021). Combined analysis of both SNPs showed that haplotype A/C was associated with increased risk of BC (P = 0.042). No significant correlation was found between rs2046210-A allele and ER status, while positive association was observed between rs204621-C allele and ER status (p= 0.005). Conclusion: Our data confirmed the important association between locus 6q25.1 and risk of BC in other populations. The frequencies of minor alleles of both significant SNPs will pave the way for a wider large-scale genome study and to be investigated with other BC risk factors.     

Infrequent Mutations in the PTEN/MMAC1 Gene among Primary Breast Cancers

Recently PTEN/MMAC1 , a candidate tumor suppressor gene, was isolated from chromosome 10q23-24 and somatic mutations of this gene were detected in several malignancies including brain, prostate, and breast tumors. To investigate further the potential role of this gene in mammary carcinogenesis, we examined 69 primary breast cancers for mutations in PTEN/MMAC1 by means of polymerase chain reaction single-strand conformation polymorphism and sequencing analysis. We detected only one somatic missense mutation, a change from T to C at codon 59 (TCA to CCA) resulting in substitution of Pro for Ser in the predicted protein. This site is located outside of phosphatase or phosphate-acceptor motifs, but this codon encodes a residue that is conserved in homologous proteins, tensin and auxilin and is likely to be crucial for normal function of PTEN/MMAC1 . Among the 69 tumors examined, three low-frequency polymorphisms were found as well, one in the non-coding region of exon 1 and one each in introns 2 and 7. Our results suggested that mutation of the PTEN/MMAC1 gene is not a major factor in the development of most primary breast cancers.     

Lack of Carcinogenicity of Quercetin in F344/DuCrj Rats

Quercetin was administered at dietary levels of 0(control), 1.25 and 5.0% to groups of 50 male and 50 female rats for 104 weeks, and then all animals were maintained without quercetin supplement for a further 8 weeks. At 5.0% quercetin, both sexes showed growth retardation throughout the study. There were no treatment-ascribed effects regarding clinical signs, mortality, urinalyses or hematology. Although serum glucose in 5.0% quercetin-treated males was significantly decreased and some relative organ weights in 5.0% groups showed statistically significant increases, these latter changes seemed to be related to the growth retardation. An increased incidence of non-neoplastic hyperplastic polyps in the cecum was noted in the 5.0% males. The incidences of cystic changes and fibroadenomas of the mammary gland, and foci (areas) of hepatocellular alteration in the 5.0% females, and liver bile duct proliferations in the 5.0% males were significantly decreased. No proliferative lesions of the urinary bladder related to treatment with quercetin were found in any rats. The incidences of several other nonneoplastic and neoplastic lesions which demonstrated statistically significant changes appeared to be related to the growth retardation or to be within the normal range, and therefore none was considered to be significant biologically. Thus, the investigation did not demonstrate any clear carcinogenic effect of quercetin on F344 rats at dietary levels of up to 5.0%.     

Mixed Phenotype Lymphomas in Thymectomized (SL/KhxAKR/Ms)F1 Mice

Lymphomagenesis in mice is determined both by genetic and epigenetic mechanisms. The inbred strain SL/Kh mice selectively develop pre-B lymphomas and AKR/Ms, T-lymphomas. In crosses between SL/Kh and AKR/Ms, an AKR-derived dominant gene Tlsm1 (Thymic lymphoma susceptible mouse-1 ) determines the type of lymphoma to be a T-lymphoma. As an approach to the role of Tlsm1 , we studied the effect of thymectomy at 1 week of age in (SL/KhxAKR/Ms)Fl hybrids. In intact F1 mice, the predominant type of lymphoma was of T-lineage, whereas in thymectomized mice, it was an unusual mixed-phenotype lymphoma. They were basically CD5⁺ B-lymphomas with a rearranged immunoglobulin gene, but carried NK1 and Mac1 on the cell surface and large lysosomal granules in the cytoplasm. Histologically, the lymphoma consisted of large lymphoblastoid cells and infiltrated the spleen, lymph node and liver. Electron microscopy and histochemistry revealed numerous cytoplasmic granules containing acid phosphatase and lysozyme. These morphological features are suggestive of large granular lymphocytes. They expressed interleukin-4, perforin, and interferon-γ. On transplantation, these lymphoma cells grew equally well in intact and thymectomized F1 recipients.