Oral cytology assessment by flow cytometry of DNA adducts, aneuploidy, proliferation and apoptosis shows differences between smokers and non-smokers

Oral cytology and morphometric staining is used to identify malignant keratinocytes in oral premalignant or malignant lesions. To detect and to begin to assess changes in oral keratinocytes exposed to tobacco-derived carcinogens, which are at risk for malignant transformation, a novel method is required. The approach uses oral cytology harvested oral keratinocytes analyzed using flow cytometry (FC) for changes in DNA content, damage, cell cycle and apoptosis. Six smoker and six non-smoker oral keratinocytes were evaluated using flow cytometry in the form of laser scanning cytometry (LSC) and laser microdissection (LMD). Among smokers compared to non-smokers, the method detected and assessed DNA damage from tobacco smoke exposure quantifying an enhanced formation of DNA adducts, such as, 8-hydroxy-2′-deoxyguanine (8-OHdG) which creates oxidation lesions and benzo[a]pyrene(B[a]P), which produces a B[a]P)-N2-dG bulky adduct. Increased DNA content, aneuploidy, percentage of cells in synthesis (S) and G₂+Mitosis (M), and apoptosis were recorded. Tissue and cell controls were used to verify these relationships. Data suggested healthy smokers were at increased risk for malignant transformation of oral keratinocytes because of the changes stated above. Using identical methods, keratinocytes exposed to the tobacco derived carcinogen, B[a]P parallel results obtained from smoke exposure indicating a direct link. Flow cytometric evaluation of oral cytology harvested keratinocytes can be used to measure exposure to tobacco carcinogens, and possibly establish a link to premalignant and malignant transformation before a lesion is noted.     

p53: guardian of ploidy

Aneuploidy, often preceded by tetraploidy, is one of the hallmarks of solid tumors. Indeed, both aneuploidy and tetraploidy are oncogenic occurrences that are sufficient to drive neoplastic transformation and cancer progression. True to form, the tumor suppressor p53 obstructs propagation of these dangerous chromosomal events by either instigating irreversible cell cycle arrest or apoptosis. The tumor suppressor Lats2, along with other tumor inhibitory proteins such as BRCA1/2 and BubR1, are central to p53-dependent elimination of tetraploid cells. Not surprisingly, these proteins are frequently inactivated or downregulated in tumors, synergizing with p53 inactivation to establish an atmosphere of "tolerance" for a non-diploid state.     

全自动细胞图像分析仪在胸腹腔积水诊断中的应用

背景与目的:胸腹水积良恶性细胞诊断是临床细胞病理上的一个难点,有多种方法用于胸腹积水细胞性质的鉴定,但因复杂而鲜在临床使用.本研究试用DNA全自动图像分析研究恶性胸腹积水细胞中的非整倍体细胞.方法:每例胸腹积水样本50～100 mL经离心去掉上清液,经涂片离心机制成2张玻片.一张玻片用Feulgen染色,用DNA倍体分析仪测定DNA含量:另一张作为对照,经瑞士染色作常规细胞学诊断.结果:463例胸腹积水中,经临床证实有203例为炎性积水,240为痛性积水,20例临床诊断不明.203例炎性积水中,有8例发现1～2个大于5c非整倍体细胞,其余均未见异常倍体细胞;而常规细胞学诊断193例为炎性积水,10例可疑核异质.在240例癌性积水中,DNA倍体分析除7例外,均发现有非整倍体细胞,其中包括6例1～2个大于5c细胞,81例3个或3个以上的大于5c细胞,146例可见异倍体细胞峰;而常规细胞诊断为177例转移性腺癌,16例淋巴瘤、30例间皮细胞瘤,17例发现核异质.20例临床诊断不明病例中DNA倍体分析发现有4例未见倍体异常细胞,16例有非整倍体细胞,其中包括14例1～2个大于5c细胞,2例3个以上大于5c细胞:常规细胞均可见核异质.结论:在大多数癌性胸腹积水中均可见到大于5c异倍体细胞及异倍体细胞峰,DNA倍体分析方法可用于鉴别诊断癌性或炎性胸腹积水.     

HepG2细胞染色体着丝粒点变异的研究

背景与目的:探讨HepG2瘤细胞染色体着丝粒点(Cd)的变异与其非整倍性畸变的关系.材料与方法:用Cd-NOR同步银染分析技术研究HepG2细胞染色体Cd的变异.结果:HepG2细胞染色体Cd缺失率为2.30%、Cd迟滞复制率为1.02%、小Cd率为2.58%、Cd-NOR融合率为0.64%;与正常人胚胎绒毛细胞染色体Cd变异相比较,HepG2细胞染色体Cd缺失、Cd迟滞复制和小Cd升高,而Cd-NOR融合差异无显著性.结论:HepG2细胞染色体非整倍性畸变的途径可能主要涉及Cd缺失、Cd迟滞复制、小Cd.     

Cyclin D1 promoter -56 and -54 bp CpG un-methylation predicts invasive progression in arsenic-induced Bowen’s disease

Background

Patients with arsenic-induced Bowen’s disease (As-BD) are at risk of developing invasive cancers in the skin, lung, and urinary bladder. However, a longitudinal follow-up study on the association between As-BD and invasive cancers is still lacking.

晚裂胚胎性染色体及18号染色体非整倍体分析

目的：分析晚裂胚胎性染色体及18号染色体数目异常情况。方法：应用荧光原位杂交技术检测晚裂胚胎X、Y及18号染色体的非整倍体情况,并与低评分的双原核（2PN）胚胎进行比较。结果：共收集85个胚胎,其中晚裂胚胎45个（不考虑形态学评分）,成功固定269个核;低形态学评分的2PN胚胎40个,成功固定243个核,用CEPX/Y、CEP18染色体探针对85个胚胎共512个核进行荧光原位杂交。晚裂胚胎组的染色体数目异常率为45.7%,其中性染色体异常率为34.5%,18号染色体异常率为38%;2PN胚胎组的染色体异常率为48.5%,其中性染色体异常率为32%,18号染色体异常率为39%。2组性染色体和18号染色体的异常率差异均无统计学意义。结论：晚裂胚胎性染色体及18号染色体数目有较高的异常发生率,与低形态学评分的2PN胚胎一样,均不适合宫腔内移植。     

Spindle Assembly Checkpoint as a Potential Target in Colorectal Cancer: Current Status and Future Perspectives

Colorectal cancer (CRC), one of the most common malignancies worldwide, is often diagnosed at an advanced stage, and resistance to chemotherapeutic and existing targeted therapy is a major obstacle to its successful treatment. New targets that offer alternative clinical options are therefore urgently needed. Recently, perturbation of the spindle assembly checkpoint (SAC), the surveillance mechanism that maintains anaphase inhibition until all chromosomes reach the metaphase plate, has been regarded as a promising target to fight cancer cells, either alone or in combination regimens. Consistent with this strategy, many cancers, including CRC, exhibit altered expression of SAC genes. In this article, we review our current knowledge on SAC activity status in CRC, and on current anti-CRC strategies and future therapeutic perspectives on the basis of SAC targeting experiments in vitro and in animal models.     

Flow cytometric measurement of ploidy and proliferative activity of carcinomas of the oropharyngeal mucosa

Summary The most important indicator of ploidy and cell cycle stage in ortho-and pathologous tissues is the nuclear DNA content. To study this parameter of malignancy in squamous carcinomas of the oral, pharyngeal, or laryngeal mucosa we analyzed DNA histograms by aid of flow cytophotometry after using pepsin digestion of tumor specimens for cell dispersal and fluorochromation with combined ethidium bromide and mithramycin.In 30 of 36 tumor tissue specimens aneupoid states of nuclear DNA content (83%) were recognized, in some cases only by comparing tumor cells with admixed diploid human reference cells. All but two tumors (with hypodiploid DNA pattern) exhibited hyperdiploid stem line abnormalities, one specimen even exhibited them with triclonal DNA distribution pattern. The degree of ploidy (DNA index), defined as the ratio of peak modal channel number for the G_1/0 proportion of tumor cells to that of normal cells, ranged from 0.59 to 3.24 (mean 1.58). Cell cycle analysis of untreated squamous carcinomas, calculated by the relative DNA distribution pattern in histograms, also offered a considerable variation in proliferative activity.Kindly supported by the Deutsche Forschungsgemeinschaft (SFB 118)