DNA distribution pattern of the so-called severe dysplasias and small carcinomas of the colon and rectum and its possible significance in the tumor progression

Intratumor Mycoplasma promotes the initiation and progression of hepatocellular carcinoma

The carcinogenesis and progression of hepatocellular carcinoma (HCC) are closely related to viral infection and intestinal bacteria. However, little is known about bacteria within the HCC tumor microenvironment. Here, we showed that intratumoral Mycoplasma hyorhinis (M. hyorhinis) promoted the initiation and progression of HCC by enhancing nuclear ploidy. We quantified M. hyorhinis in clinical tissue specimens of HCC and observed that patients with high M. hyorhinis load had poor prognosis. We found that gastrointestinal M. hyorhinis can retrogradely infect the liver through the oral-duodenal-hepatopancreatic ampulla route. We further found that the increases in mononuclear polyploidy and cancer stemness resulted from mitochondrial fission caused by intracellular M. hyorhinis. Mechanistically, M. hyorhinis infection promoted the decay of mitochondrial fusion protein (MFN) 1 mRNA in an m6A-dependent manner. Our findings indicated that M. hyorhinis infection promoted pathological polyploidization and suggested that Mycoplasma clearance with antibiotics or regulating mitochondrial dynamics might have the potential for HCC therapy.

Oncogenic BRAF induces whole-genome doubling through suppression of cytokinesis

Melanomas and other solid tumors commonly have increased ploidy, with near-tetraploid karyotypes being most frequently observed. Such karyotypes have been shown to arise through whole-genome doubling events that occur during early stages of tumor progression. The generation of tetraploid cells via whole-genome doubling is proposed to allow nascent tumor cells the ability to sample various pro-tumorigenic genomic configurations while avoiding the negative consequences that chromosomal gains or losses have in diploid cells. Whereas a high prevalence of whole-genome doubling events has been established, the means by which whole-genome doubling arises is unclear. Here, we find that BRAFV600E, the most common mutation in melanomas, can induce whole-genome doubling via cytokinesis failure in vitro and in a zebrafish melanoma model. Mechanistically, BRAFV600E causes decreased activation and localization of RhoA, a critical cytokinesis regulator. BRAFV600E activity during G1/S phases of the cell cycle is required to suppress cytokinesis. During G1/S, BRAFV600E activity causes inappropriate centriole amplification, which is linked in part to inhibition of RhoA and suppression of cytokinesis. Together these data suggest that common abnormalities of melanomas linked to tumorigenesis - amplified centrosomes and whole-genome doubling events - can be induced by oncogenic BRAF and other mutations that increase RAS/MAPK pathway activity.

The Controversial Role of Polyploidy in Hepatocellular Carcinoma

Polyploidy, a physiological phenomenon in which cells contain more than two sets of homologous chromosomes, commonly exists in plants, fish, and amphibians but is rare in mammals. In humans, polyploid cells are detected commonly in specific organs or tissues including the heart, marrow, and liver. As the largest solid organ in the body, the liver is responsible for a myriad of functions, most of which are closely related to polyploid hepatocytes. It has been confirmed that polyploid hepatocytes are related to liver regeneration, homeostasis, terminal differentiation, and aging. Polyploid hepatocytes accumulate during the aging process as well as in chronically injured livers. The relationship between polyploid hepatocytes and hepatocellular carcinoma, the endpoint of most chronic liver diseases, is not yet fully understood. Recently, accumulated evidence has revealed that polyploid involves in the process of tumorigenesis and development. The study of the correlation and relationship between polyploidy hepatocytes and the development of hepatocellular carcinoma can potentially promote the prevention, early diagnosis, and treatment of hepatocellular carcinoma. In this review, we conclude the potential mechanisms of polyploid hepatocytes formation, focusing on the specific biological significance of polyploid hepatocytes. In addition, we examine recent discoveries that have begun to clarify the relevance between polyploid hepatocytes and hepatocellular carcinoma and discuss recent excellent findings that reveal the role of polyploid hepatocytes as resisters of hepatocellular carcinoma or as promoters of hepatocarcinogenesis.

Polyploidy in liver development, homeostasis and disease

Polyploidy (or whole-genome duplication) is the condition of having more than two basic sets of chromosomes. Polyploidization is well tolerated in many species and can lead to specific biological functions. In mammals, programmed polyploidization takes place during development in certain tissues, such as the heart and placenta, and is considered a feature of differentiation. However, unscheduled polyploidization can cause genomic instability and has been observed in pathological conditions, such as cancer. Polyploidy of the liver parenchyma was first described more than 100 years ago. The liver is one of the few mammalian organs that display changes in polyploidy during homeostasis, regeneration and in response to damage. In the human liver, approximately 30% of hepatocytes are polyploid. The polyploidy of hepatocytes results from both nuclear polyploidy (an increase in the amount of DNA per nucleus) and cellular polyploidy (an increase in the number of nuclei per cell). In this Review, we discuss the regulation of polyploidy in liver development and pathophysiology. We also provide an overview of current knowledge about the mechanisms of hepatocyte polyploidization, its biological importance and the fate of polyploid hepatocytes during liver tumorigenesis.

The causes and consequences of polyploidy in normal development and cancer

Although nearly all mammalian species are diploid, whole-genome duplications occur in select mammalian tissues as part of normal development. Such programmed polyploidization involves changes in the regulatory pathways that normally maintain the diploid state of the mammalian genome. Unscheduled whole-genome duplications, which lead primarily to tetraploid cells, also take place in a substantial fraction of human tumors and have been proposed to constitute an important step in the development of cancer aneuploidy. The origins of these polyploidization events and their consequences for tumor progression are explored in this review.

Correlations between p53 gene mutations and histologic characteristics of pancreatic ductal carcinoma

OBJECTIVE

With the aim of improving early detection of pancreatic carcinoma, we attempted to make correlations among positive immunohistochemical detection of p53 expression, mutations in the p53 gene, and detailed histologic features of pancreatic carcinoma.

METHODS

Seven cases of invasive pancreatic ductal carcinoma demonstrating p53 overexpression were analyzed. Serial 4- and 20-microm sections from paraffin blocks were used for immunodetection of p53 protein and microdissection, respectively. We used direct sequencing of polymerase chain reaction at 101 p53-positive and 10 p53-negative sites to sequence exons 5 to 8 of p53 and then analyzed these results in concert with detailed histologic features.

RESULTS

Regardless of the degree of p53 overexpression, we detected p53 point mutations in all p53-positive lesions, including 22 noninvasive sites, 17 invasive areas, and 1 lymph node metastasis. No significant correlations were measured between specific p53 mutations and histologic features. Within individual tumors, the same p53 mutation was generally, but not always, detected in different areas in invasive and noninvasive lesions.

CONCLUSIONS

Our results demonstrate that p53 mutation is an early genetic event affecting a diversity of molecular pathways in pancreatic carcinogenesis and indicates a possibility of early diagnosis of pancreatic carcinoma by detecting a few p53-positive cells obtained from the pancreatic fluid.

Response of DNA ploidy to chemotherapy in primary and metastatic lesions in human osteosarcomas

Primary and pulmonary metastatic and pulmonary metastatic tumors (two synchronous and seven metachronous metastases) in nine patients with osteosarcomas were studied by DNA cytofluorometry. All patients were treated with both pre and postoperative chemotherapy. The results showed that all five diploid osteosarcomas and three of the four aneuploid tumors did not markedly change their ploidy pattern after preoperative chemotherapy, and had almost the same ploidy patterns as the pulmonary metastatic lesions. Those eight tumors showed poor histologic response and chemoresistance by the doxorubicin binding assay. Only one aneuploid osteosarcoma showing good histologic response and chemosensitivity changed its ploidy pattern to diploid, with the disappearance of aneuploid tumor cells and its synchronous pulmonary metastatic tumor also showed conversion to a diploid pattern with massive tumor necrosis. It is evident that those tumors showing no change in their ploidy pattern after chemotherapy were resistant to the chemotherapy. Therefore, we conclude that regardless of whether the pulmonary metastatic tumors were synchronous or metachronous, they showed the same change in their ploidy pattern as well as their chemosensitivity as the primary human osteosarcoma from which they were derived.

Prognostic significance of DNA ploidy pattern in osteosarcomas in association with chemotherapy

In this study, we analysed the DNA ploidy of osteosarcomas at biopsy and attempted to clarify the relationship between DNA ploidy pattern and prognosis. Thirty patients with non-metastatic osteosarcoma of an extremity were studied. All underwent intensive chemotherapy with doxorubicin, cisplatin and methotrexate, in addition to wide tumor resection. DNA ploidy was detected by DNA cytofluorometry, using isolated and smeared cells of biopsied tumor tissue. Twelve tumors showed a diploid ploidy pattern and 18 showed a non-diploid pattern such as aneuploidy (15 tumors) and euploid-polyploidy (3 tumors). The event-free survival rate at 9 years was 63.5% in non-diploid osteosarcoma patients and 13.3% in diploid osteosarcoma patients. There was a statistically significant difference between the two groups (P = 0.0278). These results lead us to conclude that a non-diploid osteosarcoma may be more sensitive to chemotherapy than a diploid tumor.

Human neuroblastoma demonstrating clonal evolution in vivo

Neuroblastoma demonstrates various clinical behaviors, ranging from spontaneous regression to rapid progression regardless of the therapy used. To study the possibility that progression occurs in neuroblastoma through the accumulation of genetic aberrations, we analyzed the clonal constitution of the primary tumor and metastatic tumor samples from a stage-4 patient. Using cytofluorometry and FISH analyses, intratumor clonal heterogeneity was revealed. In the initial primary tumor sample, the nuclear DNA content indicated the coexistence of diploid and aneuploid clones, and the copy number of chromosome 1 varied from two to six. The chromosome 1 aneusomy population was composed of MYCN-amplified and 1p-deleted clones, whereas, in the chromosome 1 disomy population, coexistence of MYCN-amplified and non-amplified clones as well as 1p-deleted and 1p-intact clones was revealed. In the primary tumor after chemotherapy, the DNA-diploid component had become predominant, although the coexistence of MYCN-amplified and non-amplified clones could still be demonstrated in poorly- and well-differentiated tumor regions, respectively. This contrasted with the findings in the metastatic tumors, in which either diploid or aneuploid clone with MYCN amplification and 1p deletion dominated completely in each metastatic site. The findings suggest that the aneuploid clones had evolved from a diploid clone with MYCN amplification and a 1p deletion which, in turn, may have evolved from a diploid clone with neither MYCN nor 1p abnormality. This illustrates how various stages of multiple-step tumorigenesis may provide clues to a better understanding of the clinical heterogeneity of neuroblastoma.

Ploidy analysis in paraffin-embedded malignant fibrous histiocytoma by DNA cytofluorometry and flourescence in situ hybridization

To prove the relationship between chromosomal aberration and DNA ploidy in human malignant fibrous histiocytoma (MFH), fluorescence in situ hybridization (FISH) and DNA cytofluorometry were performed in this study. For FISH study, the nucleus of each tumor cell was isolated from paraffin-embedded tissue of nine MFHs. Five chromosome-specific DNA probes (1p36, 1q12, 8q21.3, 11 centromere, and 17 centromere) were hybridized on cell nuclei. Cells with more than three probe signals were regarded as chromosome polysomy. All of the tumors analyzed by FISH had extra copies. The average percentage of polysomy in all tumors was high, ranging from 10.2% to 49.2%. The DNA ploidy patterns, and the percentage of hyperdiploid cells showing a greater DNA content than diploid cells, were obtained from DNA cytofluorometry. Three of nine were diploid patterns and six were non-diploid patterns, and the percentage of hyperdiploid cells in all tumors was high, ranging from 9.1% to 61.9%. The percentage of polysomy could be correlated with the percentage of hyperdiploid cells in each cell. In this study, we found that the DNA ploidy change was closely correlated with aberrations of chromosome copy number in MFH. In addition, the alterations of specific chromosome copy number could be detected in MFH showing diploid cells. Thus, these data indicate that FISH and DNA cytofluorometry are available as a cytogenetic tool for the analysis of interphase nuclei of bone and soft tissue tumors including MFH.

Genetic heterogeneity in sporadic colorectal adenomas

The majority of colorectal cancers develop from adenomatous polyps under the influence of factors that are still poorly understood. Tumourigenesis is generally considered a multistep process in which multiple genetic alterations occur, eventually reflected in abnormalities of the cellular DNA content. Macroscopical features such as tumour size and tumour architecture (tubular, tubulovillous, or villous) are correlated wit the chance of malignancy in the lesion. Grade of dysplasia can be considered an indicator for the level of progression of the adenoma towards invasive carcinoma. These characteristics were correlated with the presence or absence of K-ras mutations and the DNA ploidy in a prospective study performed on 46 large sporadic colorectal adenomas resected by endoscopy. DNA ploidy and K-ras mutations were analysed in two samples taken at distant sites in the adenomas. Aneuploidy was present in 12 adenomas (26 per cent) and K-ras mutations occurred in 26 (57 per cent). A highly significant correlation was found between aneuploidy and adenoma size, architecture, and grade of dysplasia. The presence of K-ras mutations was significantly correlated only with the size of the adenomas. The proportion of adenomas with aneuploidy and/or a K-ras mutation increased when two samples were analysed instead of one. This observation suggests that the prevalence of genetic mutations and of aneuploidy is probably underestimated, as generally only one sample is investigated. No correlation was observed between K-ras mutations and ploidy. This study demonstrates the presence of genetic heterogeneity in colorectal adenomas and supports the notion that K-ras mutation is an early event, while aneuploidy is a late event in the adenoma-carcinoma sequence.

Fluorescence image cytometry for measurement of nuclear DNA content in surgical pathology

A study was made on various methodological aspects of fluorescence image cytometry (FICM) for measurement of nuclear DNA content by using CCD cameras attached to an epifluorescence microscope. Cell nuclei of paraffin-embedded specimens from mouse tissues and human prostate carcinomas were isolated and stained with 4'-6-diamidino-2-phenylindole (DAPI). We found that fluorescence fading, lamp stability, and the homogeneity of the illumination can easily be controlled. A camera with a signal-to-noise ratio of 53 dB gave a slightly more precise measurement than did a 46-dB camera. The linearity of the analysis results was very good. The coefficient of variation of mouse kidney standard cells in the DNA histograms was about 5% and 7.4% in histograms of prostate carcinoma biopsies. Stained cell nuclei can be stored for long periods at -20 degrees C without impairment of quality. Comparative measurements of ploidy by FICM and flow cytometry confirmed the accuracy of the FICM analyses. Thus, FICM appears to be an easy method for quantifying the DNA content of visually inspected cell nuclei in surgical pathology.

Heterogeneity and progression of renal cell carcinomas as revealed by DNA cytofluorometry and the significance of the presence of polyploid cells

With special attention to the presence of polyploid cells, we examined heterogeneity and progression of renal cell carcinomas. We separated 116 blocks from 51 tumors into several specimens according to the histologic findings, and analyzed their DNA ploidy patterns. Thirty-one tumors (61%) were aneuploid, 29 of which showed intratumoral DNA ploidy heterogeneity. Diploid cell lines were observed in 47 tumors (92%). Polyploid cells in the diploid component were more frequently found in tumors with mixed diploid and aneuploid patterns than in the purely diploid tumors. Of the diploid cases, higher stage cases tended to have a higher incidence of polyploid cells than the lower stage cases. The incidence of aneuploid cases and DNA heterogeneity became greater as the tumors progressed. Aneuploid cases had a poorer outcome than did the diploid cases. If diploid cases with polyploid cells were classified as aneuploid cases, the difference in the survival rate between the diploid and aneuploid cases became more significant. Diploid renal cell carcinomas with polyploid cells may be an intermediate stage between diploidy and aneuploidy. Analyzing renal cell carcinomas for the presence of polyploid cells is useful for differentiating diploidy, which is actually aneuploid, from pure diploidy.

Cytophotometric and flow cytometric DNA content of isolated glands in gastric neoplasia

The gland isolation method was applied to various gastric lesions to measure DNA content by cytophotometry and flow cytometry for the first time. By incubating and agitating fresh specimens from surgically resected stomachs in calcium-magnesium free Hanks's balanced salt solution (CMFH) containing EDTA, many neoplastic glandular epithelial cells were successfully isolated from the stroma, and their characteristic three dimensional features were seen morphologically. The DNA content of pure nuclear suspensions of isolated glands was obtained by cytophotometry and flow cytometry staining with 4',6-diamino-2-phenylindole dihydrochloride (DAPI) and propidium iodide, respectively. Compared with histological grading, the frequency of the DNA aneuploidy of cancer with moderate or poor differentiation by cytophotometry (75%) was significantly higher than that of well differentiated cancer (25%), but the histological typing of gastric cancer DNA frequency were not correlated. This method allowed us to detect small aneuploid peaks by flow cytometry, which were previously masked by contaminating interstitial cells. The frequency of DNA aneuploidy detected by flow cytometry (87.5%) was higher than detected by cytophotometry (58.3%). The results of these studies shows the feasibility of this technique for analysing the DNA content of various lesions of the stomach.

DNA amplifications and elevated expression of proto-oncogene in addition to altered DNA ploidy in metastatic brain tumors

The histopathological characteristics, proto-oncogene amplification, immunohistopathology of the c-erbB-2 product distribution, and the DNA content of nuclei were examined in metastatic brain tumors, which consisted of seven adenocarcinomas, a large cell carcinoma, a squamous cell carcinoma, a renal cell carcinoma and a mucoepidermoid carcinoma. A very high incidence of DNA changes was seen in these tumors. Proto-oncogene amplification and abnormal DNA content in the nuclear portion were found in 64% (7/11) and 67% (6/9) of cases, respectively. We also found double oncogene alteration in three cases metastasizing from lung, esophagus and kidney, and triple oncogene alteration in one case metastasizing from breast. We could not identify the common alterations in the group of metastatic brain tumor cells. These data suggest that the proto-oncogene amplifications and the alteration of DNA ploidy pattern may contribute to the metastatic process.

DNA densitometry of colorectal cancer

DNA analysis was assessed by densitometry for 281 cases of colorectal adenocarcinoma. Detection of aneuploidy in a single case rose from 65% if one, to 92.5% when three or more sections, were analysed. Although aneuploid tumours had significantly larger nuclear areas than near diploid tumours (p = 0.009), densitometric measurements showed no association with clinicopathological variables. DNA content determined by densitometry was compared with that from flow cytometry on 465 tissue sections from 241 cases. Aneuploidy assessed by flow cytometry was significantly associated with that determined by densitometry (p < 0.01 for all comparisons), ploidy state being similar in 381 sections (82%, kappa = 0.63, p < 0.001), and 187 cases (77.6%, kappa = 0.57, p < 0.001). Univariate survival analysis showed that DNA densitometric variables had no significant association with survival in (a) all cases, (b) cases without lymph node metastases, or (c) cases without distant metastases. Multivariate regression analysis of densitometric and clinicopathological variables identified Dukes's stage, patient age, and tumour differentiation as the combination of variables most closely related to survival. Densitometric measurement of DNA content could not significantly improve on the prognostic model containing these three variables. It is concluded that, although the assessment of DNA content by densitometry is comparable with that of flow cytometry, conventional histological variables remain the best predictors of prognosis in colorectal cancer.

Estimation of proliferative activity of experimental tongue carcinoma in rats. Immunohistochemical and DNA cytofluorometric analysis

Precancerous lesions and carcinomas were produced in rat tongues by oral administration of 0.001% 4-nitroquinoline 1-oxide (4NQO) in drinking water, and the biological characteristics and tumor kinetics were studied. Bromodeoxyuridine labeling index (BrdU L.I.) was determined immunohistochemically, and the nuclear DNA content was measured by DNA cytofluorometry. The BrdU L.I. was lowest in normal epithelium (3.49 +/- 0.49%), higher in papillomas (8.24 +/- 1.76%) and highest in squamous cell carcinomas (13.36 +/- 4.40%). Normal lingual epithelial cells, papillomas and 18 of the 25 squamous cell carcinomas showed a diploid pattern, while 7 squamous cell carcinomas showed a diploid plus tetraploid pattern. The correlation between polyploidization and tumor progression was significant, but the correlation between BrdU L.I. and tumor progression was not significant. The results suggest that while polyploidization of tumors increases with tumor progression the growth rate of tumors does not necessarily do so.

DNA image cytometric analysis of macroregenerative nodules (adenomatous hyperplasia) of the liver: evidence in support of their preneoplastic nature

Twenty-eight macroregenerative nodules from 14 cirrhotic patients who underwent orthotopic liver transplantation were evaluated for DNA ploidy by means of image analysis of Feulgen-stained tissue sections. The lesions were classified as type 1 (16 cases) or type 2 (12 cases) on the basis of the absence or presence of cellular or architectural atypia in the nodules. The surrounding cirrhotic nodules were evaluated for liver cell dysplasia. Aneuploid peaks were significantly more frequent in type 2 macroregenerative nodules (58.3%) than in the cirrhotic regenerative nodules (7.1%) (p < 0.007). In addition, aneuploid peaks occurred with increased frequency in type 2 nodules (58.3%) than in type 1 macroregenerative nodules (6.2%) (p < 0.02). Only two aneuploid peaks (14.2%) were found in dysplastic cirrhotic livers. The nuclear area of aneuploid hepatocytes (71.6 microns 2 +/- 10.1%, mean +/- S.D.) differed significantly from that of diploid liver cells (45.4 microns 2 +/- 6.5%) (p < 0.0001). Tetraploid peaks occurred in three type 2 lesions (25%); they were also found in one type 1 macroregenerative nodule (6.2%), one cirrhotic liver without dysplasia (7.1%) and three cirrhotic livers with dysplasia (21.4%). These findings support the notion that macroregenerative type 2 nodules are directly implicated in hepatocarcinogenesis and that their presence should be sought as an indicator of malignant potential in cirrhotic livers.

Comparative cytofluorometric DNA analysis of pleomorphic adenoma and adenoid cystic carcinoma of the salivary glands

The nuclear DNA content in the tumor cells of 17 pleomorphic adenomas (PA) and 26 adenoid cystic carcinomas (ACC) was assayed by cytofluorometry to clarify the etiology of the differences in their biological nature. Aneuploidy was found in only two solid-pattern ACC samples; all the other samples had diploid stemlines. With respect to the polyploid cell rate and the S + G2M fraction, the differences between the four histological patterns of PA were not significant. In the ACC, the S + G2M fraction was significantly higher in solid pattern than in cribriform or trabecular pattern tumors, which may indicate that proliferative activity is higher in the solid pattern than in the other two. The polyploid cell rate in ACC was significantly higher in the solid pattern than in the cribriform pattern carcinomas. There was no significant difference in the mean polyploid cell rate between PAs and ACCs. The mean S + G2M fraction was significantly higher in all histological patterns of ACCs than in PAs. These results suggest that proliferative activity is greater in any one of the histological patterns of ACC than in PA. These findings may largely explain the biological differences between the two tumors.

DNA ploidy pattern of flat adenomas of the large bowel

In an attempt to clarify the nature of "flat adenomas," DNA content was measured by means of microspectrophotometry. Thirty-nine flat adenomas (FA), 13 with mild, 22 with moderate, and 4 with severe atypia, were collected for this study. In FA, diploidy (D), polyploidy (P), and aneuploidy (A) were found 100, 0, and 0 percent in mild atypia, 41.9, 4.5, and 54.5 percent in moderate atypia, and 0, 0, and 100 percent in severe atypia, respectively. It is assumed that FA have a much higher malignancy potential than previously expected since, histologically, benign-appearing FA with moderate atypia have already contained malignant DNA patterns. In particular, those more than 5 mm in diameter show aneuploidy in 80 percent. These data suggest that FA with moderate atypia play an important role in the pathogenesis of small colonic carcinomas.

Cytofluorometric analysis of metastases from lung adenocarcinoma with special reference to the difference between hematogenous and lymphatic metastases

Metastatic tumors in the brain, liver, and regional lymph nodes (20 cases each) from patients with adenocarcinoma of the lung were examined by cytofluorometric analysis, and compared with the respective primary lung tumors. The nuclear DNA content of tumor cells was significantly increased in metastatic tumors in the brain and liver compared with the primary (P less than 0.01). However, the DNA content of metastatic tumors in regional lymph nodes was almost identical to that of the primary tumor in many instances. From the viewpoint of the nuclear DNA content of lung adenocarcinoma, blood-borne tumor cells in the brain and liver were considered likely to constitute a discrete tumor cell subpopulation, i.e., probably a more malignant one, different from the major subpopulation in the primary tumor, whereas lymphatic metastases in regional lymph nodes were similar to the primary. The subpopulation with an increased DNA content in hematogenous metastases were thought to have originated from a minor subpopulation in the primary tumor or to have developed at the metastatic site.

DNA measurements in chronic hepatitis, cirrhosis and hepatocellular carcinoma

It has been documented that chronic hepatitis may progress to cirrhosis and then develop hepatocellular carcinoma (HCC). To test whether abnormal cellular DNA increases along this line of development, liver tissues from 48 patients with chronic hepatitis, 17 with cirrhosis, and 8 with HCC were investigated for cellular DNA content with a scanning microdensitometer. Seven of 8 HCCs and 2 cirrhotic livers adjacent to HCC had abnormally increased cellular DNA content. Only 4 livers from patients with chronic liver diseases other than HCC had abnormal cellular DNA content. The cellular DNA content in livers not accompanying HCC was not related to the patient's age, histological diagnosis, and hepatitis inflammatory activity. The results confirmed the increase of cellular DNA content in HCC, but did not provide evidence of a progressively increasing DNA content from chronic hepatitis to liver cirrhosis. However, cirrhotic livers with abnormal hepatocytic DNA content deserve careful follow-up for the early detection of HCC.

DNA ploidy and proliferative activity of human pulmonary epithelium

DNA ploidy and distribution has been determined in normal and abnormal bronchial, bronchiolar and alveolar epithelium from 22 patients, aged between 0 and 85 years, 9 of whom had received chemotherapy for malignant disease. The DNA ploidy was diploid in all the specimens examined. The S + G2/M fraction was significantly greater in diseased than normal bronchial trees. In the bronchial epithelium, mean values +/- the standard deviation (SD) were 5.5 +/- 2.2% vs 1.1 +/- 0.6%, in bronchiolar epithelium 4.6 +/- 1.6% vs 1.0 +/- 0.9% and in alveolar epithelium 4.6 +/- 1.6% vs 0.8 +/- 0.5%. The highest S + G2/M value of 8.9% was obtained from inflamed bronchial epithelium. Polyploid cells up to the octaploid range occurred infrequently but their incidence was slightly increased to between 0.16% and 0.9% in diseased lungs and in patients who had received chemotherapeutic drugs. It was concluded that (1) non-cancerous drugs. It was concluded that (1) non-cancerous pulmonary epithelium is diploid, that (2) pulmonary epithelium shows steady-state renewal at all ages and polyploid cells are rare under normal conditions and that (3) the S + G2/M fraction increases up to approximately 10% in reactive proliferative states.

Problem of size dependence in fluorescence DNA cytometry

The relationship among fluorescence intensity, area, thickness, and DNA concentration of DNA-bearing polyacrylamide film, stained with 50 ng/ml DAPI, was studied using an epi-illumination cytofluorometer. Measurements and theoretical analysis suggest the inevitability of the size-dependent effect on human cell nuclei in which the order of the DNA concentration is approximately 10 mg/ml, and that this effect can be virtually negated if the nuclei are stretched and flattened to less than 0.33 microns in thickness on the smears. Alternative practical ways to minimize this effect are to decrease the dye concentration of a staining solution and to make smears as thin and uniform as possible by some means such as hypotonic treatment and/or using an automatic centrifuge smearing apparatus. The size-dependent effect, nevertheless, should be taken into account particularly when determining the DNA content of different cell types and the DNA aneuploidy of tumor cells, regardless of the technique used for measurement.

The possibility of nonpolypoid carcinogenesis in the large intestine as inferred from frequencies of DNA aneuploidy of polypoid and crater-shaped carcinomas

DNA ploidy patterns were studied by cytofluorometry in 60 cases of crater-shaped invasive carcinoma and 30 cases of polypoid tumor (severe dysplasia or submucosally invasive carcinoma located in the pedunculated, semipedunculated, or sessile polyp) of the large intestine. The data were compared with 20 cases of intramucosal differentiated (or intestinal type) adenocarcinoma of the stomach, with special reference to their macroscopic shape and frequency of DNA aneuploidy. DNA aneuploidy was found in 77% of the crater-shaped carcinomas and in 17% of the polypoid tumors of the large intestine. The frequencies were significantly different and the frequency gap amounted to 60%. However, 18 of 20 (90%) gastric adenocarcinomas were nonpolypoid in shape, whereas two (10%) were polypoid. DNA aneuploidy was found in 50% of the gastric adenocarcinomas and 56% of the nonpolypoid gastric adenocarcinomas. This value did not differ from the values reported previously for the submucosally invasive and advanced crater-shaped intestinal type adenocarcinomas of the stomach. Biologic characteristics of adenocarcinomas of the large intestine can be compared with those of intestinal type adenocarcinomas of the stomach, because intestinal type gastric adenocarcinoma is surrounded mostly by intestinalized mucosa and considered to arise from the epithelium under induction or progression of intestinal differentiation. Therefore, we inferred that the frequency gap in DNA aneuploidy between the crater-shaped and polypoid tumors of the large intestine implies that in the large intestine approximately 60% of the crater-shaped invasive carcinomas develop from the small nonpolypoid carcinomas.