Intratumoral heterogeneity in DNA ploidy of esophageal squamous cell carcinomas

Genomic Adequacy from Solid Tumor Core Needle Biopsies of ex Vivo Tissue and in Vivo Lung Masses: Prospective Study

Purpose To identify the variables and factors that affect the quantity and quality of nucleic acid yields from imaging-guided core needle biopsy. Materials and Methods This study was approved by the institutional review board and compliant with HIPAA. The authors prospectively obtained 232 biopsy specimens from 74 patients (177 ex vivo biopsy samples from surgically resected masses were obtained from 49 patients and 55 in vivo lung biopsy samples from computed tomographic [CT]-guided lung biopsies were obtained from 25 patients) and quantitatively measured DNA and RNA yields with respect to needle gauge, number of needle passes, and percentage of the needle core. RNA quality was also assessed. Significance of correlations among variables was assessed with analysis of variance followed by linear regression. Conditional probabilities were calculated for projected sample yields. Results The total nucleic acid yield increased with an increase in the number of needle passes or a decrease in needle gauge (two-way analysis of variance, P < .0001 for both). However, contrary to calculated differences in volume yields, the effect of needle gauge was markedly greater than the number of passes. For example, the use of an 18-gauge versus a 20-gauge biopsy needle resulted in a 4.8-5.7 times greater yield, whereas a double versus a single pass resulted in a 2.4-2.8 times greater yield for 18- versus 20-gauge needles, respectively. Ninety-eight of 184 samples (53%) had an RNA integrity number of at least 7 (out of a possible score of 10). Conclusion With regard to optimizing nucleic acid yields in CT-guided lung core needle biopsies used for genomic analysis, there should be a preference for using lower gauge needles over higher gauge needles with more passes. ^©RSNA, 2016 Online supplemental material is available for this article. An earlier incorrect version of this article appeared online. This article was corrected on October 21, 2016.

Chromosomal aneuploidies and combinational fluorescence in situ hybridization probe panels are useful for predicting prognosis for esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a common cancer type in China. In this study, we aimed to develop aneuploidy markers for diagnosis and prognosis of ESCC.

METHODS

Chromosomal aneuploidies were detected in 493 primary tumors and 61 precancerous lesions by fluorescence in situ hybridization with chromosome enumeration probes (CEP), and cut-off values were set by receiver operating characteristic (ROC) curves.

RESULTS

According to the cut-off values, chromosomes 3, 8, 10, 12, 17 and 20 presented frequent gains, with rates of 70.1, 69.7, 58.9, 66.9, 67.5 and 77.2 % in tumors and of 32.1, 26.8, 33.9, 41.2, 44.0 and 42.0 % in precancerous lesions. Loss of chromosome Y was detected in 72.0 % of male patients. An optimal four-probe panel CEP3/12/17/20 was established for detecting ESCC (sensitivity: 86.1 %), and CEP3/10/12/20 for precancerous lesions (sensitivity: 48.0 %). Gain of CEP8 was significantly correlated with lymph node metastasis (LNM) and late stages (P = 0.002 and 0.001), and loss of CEPY with age (P = 0.002, male). Kaplan-Meier survival curves indicated that patients with positive CEP10/17 (pT1 + T2, P = 0.041) and CEP8/17 (stages IIb + III + IV, P = 0.002) had poor overall survival. Combinations of LNM/stage and CEP panels could divide patients into more subgroups, including LNM + CEP3/17, LNM + CEP10/17, LNM + CEP3/10/17, stage + CEP3/17, stage + CEP10/17 and stage + CEP3/10/17 (P = 0.0004, 0.0003, 0.0001, 0.005, 0.001 and 0.0008, respectively). Multivariate Cox regression analysis confirmed that the above combinational models were independent prognostic factors.

CONCLUSIONS

Our data suggest that the combinational probe sets may have potential for detection and prognostic prediction of ESCC.

In vivo aneuploidization during the expansion of renal adenocarcinoma

BACKGROUND/AIMS

A correlation has been observed between DNA ploidy and other prognostic parameters such as tumor stage and grade. The present study evaluates tumor aneuploidization during renal adenocarcinoma expansion and growth.

METHODS

A total of 252 renal tumors were analyzed between 1969 and 2001. Evaluated variables were age, TNM, Fuhrman classification, histology, size and DNA. A tumor was homogeneous when all the samples were diploid or aneuploid, and a heterogeneous tumor was the coexistence of aneuploid and diploid samples, or all-aneuploid with different aneuploid clones.

RESULTS

A total of 224 tumors were included (coefficient of variation <8). The DNA study classified 129 (57.6%) as diploid and 95 (42.4%) as aneuploid. The percentage of aneuploid tumors increased significantly with the pathological stage. Both aneuploid patterns were also significantly more frequent in advanced pathological stages. Tumors with multiple aneuploid clones (n = 17) were significantly more frequent in tumors measuring `4 cm. Both aneuploid patterns showed no differences in survival (p = 0.83), indicating that the heterogeneous pattern probably represents an intermediate step between diploid and homogeneous aneuploid tumor status.

CONCLUSIONS

The aneuploid pattern is more common in more advanced stages of the disease, with no clear correlation to primary tumor size. This suggests gradual aneuploidization with tumor expansion and growth.

Prognostic significance of multidrug-resistance protein (MDR-1) in renal clear cell carcinomas: a five year follow-up analysis

Background

A large number of renal cancer patients shows poor or partial response to chemotherapy and the mechanisms have not been still understood. Multi-drug resistance is the principal mechanism by which many cancers develop resistance to chemotherapic drugs. The role of the multi-drug resistant transporter (MDR-1/P-glycoprotein), the gene product of MDR-1, and that one of the so-called multi-drug resistance associated protein (MRP), two energy-dependent efflux pumps, are commonly known to confer drug resistance.

We studied MDR-1 expression in selected cases of renal cell carcinoma (RCC), clear cell type, with long-term follow-up, in order to establish its prognostic role and its possible contribution in the choice of post-surgical therapy.

Methods

MDR-1 has been studied by standard LSAB-HRP immunohistochemical technique, in paraffin embedded RCC samples. Protein expression has been compared to clinical and histopathological data and to disease specific survival of RCC patients, by Kaplan-Meier curve and Cox multivariate regression analyses.

Results

Two groups of RCCs were obtained by esteeming MDR-1 expression and disease specific survival (obtained with Kaplan-Meier curve and Cox multivariate regression analyses): the first one presents low or absent MDR-1 expression and good survival; the second one is characterized by high MDR-1 expression and significant poor outcome (p < 0.05). Afterwards, we have found disease specific survival, adjusted for stages and independent of therapy: this difference of survival rates was statistically significant (p < 0.05). Stage adjusted disease specific survival rate, according to MDR-1 expression and therapy in patients affected by RCC in early stage (stage I), has revealed that the group of patients with high MDR-1 expression and without adjuvant therapy showed poor survival (p < 0.05). Cox multivariate regression analysis has confirmed that, in our cohort of RCC (clear cell type) patients, the strong association between MDR-1 and worse outcome is independent not only of the adjuvant therapy, but also of the other prognostic parameters (p < 0.05).

Conclusion

In our opinion, the results of this study well prove the relationship between MDR-1 expression and worse clinical prognosis in RCC, because MDR-1 over-expressing RCCs can be considered a group of tumours with a more aggressive behavior. This finding outlines a possible role of MDR-1 as prognostic factor, dependent and independent of multidrug resistance. These results could be useful to predict cancer evolution and to choose the appropriate treatment: this is another step that can stimulate further promising and interesting investigations on broader study population.

Comparison of DNA content parameters in paired, fresh tissue pretreatment biopsies and surgical resections from squamous cell carcinoma of the head and neck

OBJECTIVE

Cellular DNA characteristics derived from pretreatment biopsy (PTB) may become important for predicting treatment outcomes in patients with head and neck squamous cell cancer (HNSCC). Whether the PTB adequately represents the whole specimen is of critical importance.

STUDY DESIGN

In a series of >700 HNSCCs, we identified 59 cases in which the PTB and the surgical resection (SR) met the following criteria: PTB and SR were from the same site, and SR was obtained within 5 weeks of PTB with no intervening treatments.

RESULTS

Twenty-nine percent of the PTB specimens were DNA diploid. Only 1 of the 11 subsequent DNA diploid SR was associated with a DNA aneuploid PTB (91% concordance). Of the 48 DNA aneuploid tumors, 3 were associated with DNA diploid PTB (94% concordance). Three other DNA aneuploid SRs were associated with PTB of poor quality.

CONCLUSION

With respect to DNA ploidy, PTB are representative of SR specimens.

Intratumoral genetic heterogeneity in Barrett adenocarcinoma

In 10 cases of Barrett adenocarcinoma, samples from 8 tumor areas (including superficial and deep from peripheral and central areas) and a regional lymph node metastasis were studied for amplification of c-myc, c-erbB-2, and EGFR. We analyzed loss of heterozygosity (LOH) at 3 loci (APC, MCC, and RB) and 2 anonymous microsatellite markers (D4S1652 and D18S474). We detected c-myc in variable fractions of tissue samples from 3 of 9 tumors; EGFR was amplified in 2 specimens from 1 tumor. One tumor demonstrated amplification of c-erbB-2 in all areas. LOH at the D4S1652, MCC, RB, APC, and D18S474 loci was found in 75% (3/4), 57% (4/7), 50% (4/8), 11% (1/9), and 0% (0/10) of informative cases, respectively. LOH generally was restricted to variable subpopulations of tumor cells within individual tumors. There was no obvious association of certain genetic alterations with topographically distinct tumor regions; however, superficial areas showed more frequent genetic alterations than areas from the deeply invading front. More aberrations were detected in the periphery than in the center. Barrett adenocarcinoma is characterized by marked intratumoral genetic heterogeneity, which must be considered when evaluating genetic alterations as indicators of response to therapy and prognosis.

Nuclear DNA content-derived parameters correlated with heterogeneous expression of p53 and bcl-2 proteins in clear cell renal carcinomas

BACKGROUND

p53 and bcl-2 are two key genes involved in cell cycle and cell death regulation. Altered expression or mutation of these genes has been found in human cancers and also has been identified in clear cell renal carcinoma (RCC). Their role in RCC progression, however, is still unclear. By contrast, the prognostic significance of ploidy and S-phase fraction (SPF) have been studied extensively in RCC. To better characterize the biologic role of p53 and bcl-2 oncoproteins in RCC, we offer a multisample correlative analysis of the expression of these two proteins with ploidy and SPF.

METHODS

Ploidy and SPF along with p53 and bcl-2 expression were analyzed in 296 specimens, selected by multiple sampling of 33 consecutive operable RCCs. The expression of p53 and bcl-2 proteins was studied by immunohistochemistry, and SPF and tumor ploidy were studied by flow cytometry.

RESULTS

In our study, 4 of 32 (12.5%) were found to be diploid, and 28 of 32 (87.5%) cases showed an abnormal DNA content. Among the aneuploid tumors, 14 of 28 (50%) were multiploid. Heterogeneous DNA content was detected in 21 of 32 (65.6%) tumors and was correlated with the more advanced Robson stage tumor (P = 0. 03). Intratumor heterogeneity also was detected for p53 and bcl-2 protein expression. Expression of p53 protein correlated with the lack of bcl-2 protein expression (P = 0.0032), aneuploidy (P < 0. 0001), and high SPF (P = 0.0006), whereas bcl-2 expression was associated with a normal DNA content (P < 0.0001) and low SPF (P = 0. 035).

CONCLUSIONS

Within each RCC, p53 and bcl-2 expression is markedly heterogeneous. Our results depicted a scenario in which bcl-2 protein, expressed by normal renal parenchyma, is still present in euploid cell clones of RCC but disappears during the progression of renal neoplasm toward a more aggressive phenotype characterized by overexpression of p53 protein, aneuploidy, and high SPF.

The mitotic machinery as a source of genetic instability in cancer

Development and growth of all organisms involves the faithful reproduction of cells and requires that the genome be accurately replicated and equally partitioned between two cellular progeny. In human cells, faithful segregation of the genome is accomplished by an elaborate macromolecular machine, the mitotic spindle. It is not difficult to envision how defects in components of this complex machine molecules that control its organization and function and regulators that temporally couple spindle operation to other cell cycle events could lead to chromosome missegregation. Recent evidence indicates that the persistent missegregation of chromosomes result in gains and losses of chromosomes and may be an important cause of aneuploidy. This form of chromosome instability may contribute to tumor development and progression by facilitating loss of heterozygocity (LOH) and the phenotypic expression of mutated tumor suppressor genes, and by favoring polysomy of chromosomes that harbor oncogenes. In this review, we will discuss mitotic defects that cause chromosome missegregation, examine components and regulatory mechanisms of the mitotic machine implicated in cancer, and explore mechanisms by which chromosome missegregation could lead to cancer.

Prognosis of esophageal squamous cell carcinoma: analysis of clinicopathological and biological factors

OBJECTIVE

Esophageal squamous cell carcinoma (ESCC) is rather common among the Chinese, but the therapeutic outcome is dismal. Knowledge of the prognostic factors in cancerous patients may influence therapeutic strategy. However, systemic analyses of clinicopathological and biological factors for patients with ESCC are few, and the results are controversial.

METHODS

Between 1985 and 1996, 117 patients undergoing en bloc esophagectomy and gastric substitution were enrolled. None had neoadjuvant treatment. Postoperative adjuvant therapy was provided for patients at and beyond stages IIa. Clinical responses were followed routinely. Flow cytometry was used to measure DNA ploidy and synthesis-phase fraction (SPF) of the resected esophageal tissues from all patients. Immunohistochemistry was also used to examine the expression of proliferating cell nuclear antigen (PCNA), epidermoid growth factor receptor (EGFR), HER-2/neu, and p53 in the pathological sections. Clinical correlation was evaluated by chi2 with Fisher's exact test, and survival by log-rank test.

RESULTS

The overall survival rates were 74% for 1 yr, 48% for 3 yr, and 38% for 5 yr. TNM tumor staging, the number of diseased lymph nodes (N < or = 3 or N > 3), degree of cell differentiation, DNA ploidy, SPF, and lymphovascular invasion were more useful than biological markers, such as PCNA, EGFR, HER-2/neu, and p53, for the prognosis of ESCC. Multivariate analysis revealed significant correlation of tumor staging and number of diseased lymph nodes with patient survival after surgery.

CONCLUSIONS

En bloc esophagectomy may provide a rather satisfactory survival rate for patients with early stage ESCC. However, for patients with distant lymph node metastasis and those with more than three lymph nodes involved, radical surgical resection, even combined with postoperative chemoradiotherapy, cannot improve survival. The prognostic value of biological markers, including PCNA, EGFR, HER-2/neu, and p53, however, is limited.

Flow-cytometric DNA content analysis of oesophageal carcinoma. Comparison between tumour and sequential non-tumour mucosae

The DNA content in oesophageal carcinoma and in sequential non-tumour mucosa was evaluated in 35 patients with oesophageal carcinoma, to explore the hypotheses that DNA distribution pattern and S-phase fraction can reflect malignant potential and that DNA aneuploidy can provide an early-warning signal of developing cancer. DNA flow cytometry was performed on 129 specimens from the tumours and on 119 specimens from non-tumour mucosa. Control specimens from gastric fundus had normal diploid DNA content and low S-phase fraction. Aneuploidy was found in 94.3% of the carcinoma specimens and intratumoral heterogeneity in 54.3%. Of the non-tumour specimens, 43.7% showed aneuploidy and none multiple aneuploidy. Pattern III distribution was present in 8.6% of the tumour specimens but not in non-tumour mucosa, where the incidence of aneuploidy rose with closeness to the tumour (p < 0.001). S-phase fraction was smaller in non-tumour than in tumour specimens (p < 0.0001). The study indicated that histologically tumour-free oesophageal mucosa may have a high malignant potential in patients with oesophageal carcinoma. The relative instability of such mucosa, with aneuploid cells and low S-phase fraction, may facilitate transition to abnormally proliferating cells in response to environmental signals. Cigarette smoking and alcohol may increase the risk of multicentric cancer development.

Overexpression of cyclin-D1, bcl-2, and bax proteins, proliferating cell nuclear antigen (PCNA), and DNA-ploidy in squamous cell carcinoma of the oral cavity

The prognostic role of the expression of bcl-1, bcl-2, bax, PCNA, and DNA-ploidy in a series of 25 oral squamous cell carcinoma (SCC) was investigated. The average age of the patients was 62.04 years (range, 27 to 81 years), with a sex ratio (M/F) of 23:2. The follow-up mean time was 2.24 years (range, 8 months to 8 years from surgery). Immunohistochemistry for PCNA, bcl-2, bcl-1, and bax proteins was carried out on 5-microm serial sections from formalin-fixed, paraffin-embedded tissue. The findings were compared with clinicopathologic data and with follow-up. The statistical evaluation of the results of the current study suggests that the low positivity for PCNA with a high positivity for bcl-2 protein are related to a better clinical behavior of the tumors. By converse, a high expression of PCNA, bax, and bcl-1 appears to correlate with a worse prognosis. All of our cases of SCC showed the presence of aneuploid populations, which was not correlated with the clinicopathologic parameters or with the overexpression of bcl-1, bcl-2, bax, and PCNA. Therefore, the aneuploidy per se did not predict the clinical evolution for the single cases of cancers. Nevertheless, once the parameters considered for the evaluation of DNA were examined in detail, it appeared that some of them, individually or combined with each other or with the expression of bcl-1, bcl-2, and bax, gained statistical significance in predicting the clinical evolution of SCC of our series. Particularly, high values of 2cDI and DNA-MG and the absence or reduction of the euploid population were associated with a short interval between surgery and recurrence or death, and this significance persisted when the simultaneous presence of overexpression of bcl-1 was considered.

Representativity of incisional biopsies for the assessment of flow cytometric DNA content in head and neck squamous cell carcinoma

DNA flow cytometry studies of squamous cell carcinoma of the head and neck have shown that patients with diploid tumours have favourable prognoses, whereas the outcomes of those with DNA aneuploid tumours are poor. DNA flow cytometry is therefore increasingly used as an integral part of diagnostic procedures. To evaluate how representative biopsies predict the DNA ploidy of oral carcinomas, incisional biopsies taken pretherapeutically from 256 tumours were compared with the corresponding surgical resection specimens. Sixty-six tumours exclusively displayed cells with flow cytometrically diploid DNA content in both the biopsy and the subsequent resection specimen, while 182 carcinomas expressed DNA aneuploid tumour cell lines in matched samples. There were only 8 tumours (3.1%) with heterogeneity in the DNA ploidy status between the biopsy and the resection specimen. These results emphasise the usefulness of incisional biopsies to reliably prognosticate the DNA ploidy status of oral carcinomas.

DNA index as a significant predictor of recurrence in colorectal cancer

PURPOSE

To clarify the prognostic significance of the DNA content in cases of colorectal cancer, we investigated the relationship between the DNA content, as determined by the DNA ploidy or DNA index, and disease-free survival.

RESULTS

This study included 201 cases that were treated by curative surgery between 1989 and 1995 at our hospital. 68 were diploid and 133 were aneuploid. The mean DNA index of these tumors was 1.42. Recurrence occurred in 30 cases (14.9 percent). Tumor site, venous invasion, Dukes stage, DNA ploidy (diploid or aneuploid), and a DNA index (less than or greater than 1.4) correlated well with disease-free survival. A multivariable analysis suggested the DNA index to be a stronger predictor than DNA ploidy. Patients with aneuploid tumors had shorter disease-free survival than those with diploid tumors (P = 0.011), especially in Dukes Stage C cases (P = 0.0209). Patients with a DNA index greater than 1.4 also had a shorter disease-free survival than those with a DNA index less than 1.4 (P < 0.001), especially in Dukes Stage C cases (P = 0.0033).

CONCLUSIONS

The DNA index value (less than or greater than 1.4) seems to be a stronger predictor than DNA ploidy (diploid or aneuploid), and the combination of Dukes stage, tumor site, and a DNA index is, therefore, considered to be clinically valuable in predicting recurrence in cases of colorectal cancer.

Cytofluorometric DNA analysis by stathmokinetic method of experimental thyroid neoplasms in rats

Thyroid neoplasms were induced in rats by the intraperitoneal injection of N-bis(2-hydroxy-propyl)nitrosamine as a carcinogenic substance and by the oral administration of KCIO4 as a promoter. The nuclear DNA content was measured in tissue sections of the tumors by the stathmokinetic method with the use of vincristine, and was correlated with the histopathological findings in the process of tumorigenesis and progression. Histological examination showed various types of lesions were produced in 47 surviving rats. A diploid pattern was seen in 82 (92%) of 89 tumors and an aneuploid pattern in 7 (8%) of 89 tumors. Papillary carcinomas and mixed carcinomas only had a diploid pattern, while two of 17 follicular carcinomas and five of 13 anaplastic carcinomas had an aneuploid pattern. On the other hand, benign proliferative nodules only had a diploid pattern. DNA heterogeneity was noted in seven malignant tumors. In four of them it was associated with the histopathological evidence of change, but in three there was no histological difference between the aneuploid and diploid areas other than a difference in the mitotic index. Mitotic indices were significantly higher in the aneuploid than in the diploid areas. These findings suggest that changes in the DNA ploidy cause histological abnormalities and/or affect the mitotic index. It is hypothesized that a change occurs in some diploid cells in a region of a tumor, and that aneuploid cells develop from the diploid cells which then acquire high proliferative activity.

Progression of hepatocellular carcinoma as reflected by nuclear DNA ploidy and cellular differentiation

BACKGROUND/AIMS

Intratumor heterogeneity of DNA ploidy within a single hepatocellular carcinoma is not well understood. The present study was designed to examine the histologic distribution of intratumor DNA ploidy in hepatocellular carcinomas of different growth types in relation to cell differentiation.

METHODS

Twenty patients (16 men and four women; mean age, 60.2 years) with hepatocellular carcinoma (mean diameter, 4.3 cm) were studied. One hundred and twenty-seven samples from different sites of each tumor were analyzed by determination of the nuclear DNA content and histological examination.

RESULTS

The DNA ploidy was heterogeneous in nine (45%) of the 20 tumors. Five tumors had a mixture of diploid and aneuploid regions, and the remaining four consisted of aneuploid regions with different DNA indices. There was no significant difference in patient characteristics between the heterogeneous and homogeneous groups. A significant correlation was found between tumor growth type and the incidence of heterogeneity. Only 16% of single nodular carcinomas without intratumor septal formation exhibited heterogeneity, while single nodular tumors with septal formation or confluent multinodular tumors were associated with high incidences of different DNA ploidy patterns or DNA indices. There was no aneuploidy in well-differentiated foci, while aneuploidy was frequently found in moderately or poorly differentiated foci (incidences of 67% and 74%, respectively).

CONCLUSIONS

Heterogeneity of DNA ploidy may develop along with changes in growth pattern and cell dedifferentiation or by confluence of nodules originating from different tumor cell clones.

Amplification of the c-erbB-2 gene detected by FISH in gastric cancers

The amplification and overexpression of the c-erbB-2 gene are considered to be implicated in the process of carcinogenesis of a variety of human tumors. The amplification and overexpression of c-erbB-2 were investigated in 48 surgically resected human gastric cancers by means of fluorescence in situ hybridization and immunohistochemistry. DNA ploidy was determined by flow cytometry. The c-erbB-2 amplification was demonstrated as a cluster of signals, suggesting homogeneously staining region (HSR), in three tumors (6.3%) accompanied by the overexpression of its protein. Such overexpression was detected in another tumor without amplification of the c-erbB-2 gene. All tumors with amplification and overexpression of c-erbB-2 were differentiated adenocarcinoma histologically, but only 10.3 and 13.8% of differentiated carcinomas showed amplification and over-expression of the c-erbB-2 gene, respectively. There was no relationship between the amplification and overexpression of c-erbB-2 and the depth of tumor invasion and lymph node involvement. Three of four cases with overexpression of c-erbB-2 were classified into DNA aneuploid tumor.

Heterogeneity of DNA content in multiple synchronous hepatocellular carcinomas

Heterogeneity of DNA content in multiple hepatocellular carcinomas (HCCs) was investigated by flow cytometry in 62 tumours from 26 patients who had undergone surgical treatment for multiple synchronous HCCs. Heterogeneity of DNA content was defined (a) when tumours had a different DNA ploidy pattern or (b) when the difference in the DNA index of the aneuploid clone was more than 0.1. A tumour with DNA aneuploidy was observed in 17 (66%) of the 26 patients. Heterogeneity of the DNA content was demonstrated in 12 (46%) out of 26 patients: in ten cases by definition (a) and in two cases by definition (b). Histological examination revealed that, of the 12 patients with a heterogeneous tumour DNA content, seven (58%) had a heterogeneous and the remaining five (42%) had a homogeneous type and grade of differentiation among the tumours, showing the absence of a relationship between histological heterogeneity and DNA content. The present results suggest the clinical relevance of DNA content analysis for identifying the clonal origin of multiple HCCs.

Use of flow cytometry in the analysis of stage III squamous cell carcinoma of the oesophagus and its association with MIB-1

AIMS

To examine the prognostic and pathobiological importance of DNA content in oesophageal squamous cell carcinomas in Hong Kong Chinese subjects; to evaluate its association with the immunohistochemical proliferative marker MIB-1.

METHODS

Paraffin wax embedded tumour tissue and adjacent normal tissue (control tissue) samples from 45 resected stage III oesophageal squamous cell carcinomas were studied using flow cytometric analysis. The DNA content and the clinicopathological data of these patients were analysed together with the MIB-1 labelling index.

RESULTS

DNA aneuploidy was present in 14 (31%) of the 45 cases. However, the DNA content did not correlate significantly with the age, sex, or survival of the patients, nor the length, location, differentiation and MIB-1 labelling index of the oesophageal carcinomas. The synthetic (S) phase fraction of diploid tumours bore no relation to the patients' survival or MIB-1 score.

CONCLUSIONS

Flow cytometry was not as useful as the MIB-1 labelling index in predicting the biological characteristics of the tumours and the prognosis of patients with oesophageal squamous cell carcinomas. This study does not support the routine use of DNA flow cytometric analysis in oesophageal cancers.

DNA ploidy and S-phase fraction of neoplastic and non-neoplastic lesions of the human gallbladder

Studies on the cell kinetics of the human gallbladder are difficult because of epithelial degeneration by bile. Using the epithelial isolation technique, however, we were able to determine the degree of degeneration and to examine the cell kinetics of gallbladder lesions in freshly resected surgical specimens. Normal and neoplastic epithelia were isolated nonenzymatically from freshly resected gallbladder. The nuclear DNA content and S-phase fraction were estimated in 110 patients with gallbladder lesions by flow cytometry (FCM). Normal tissues and all lesions except carcinomas were diploid. The S-phase fraction of gallstone cases was significantly higher (1.47 +/- 0.70%; mean +/- SD) than normal (0.79 +/- 0.39%) (P < 0.0006). All gallbladder carcinomas were multiploid, and their S-phase fraction was 11.63 +/- 3.65%. Cell renewal of normal gallbladder is low. In the gallstone cases, the S-phase fraction was increased, possibly correlated with carcinogenesis.

Heterogeneity in renal cell carcinoma and its impact no prognosis--a flow cytometric study

In the process of tumour progression genetic instability is the basis for the evolution of tumour cell clones with various genotypic and phenotypic characteristics causing heterogeneity. Renal cell carcinoma has a long prediagnostic growth period, which increases the probability of clonal evolution. We have studied 200 consecutive renal cell carcinomas, addressing the interrelationship between intratumour heterogeneity and clinicopathological factors. DNA ploidy patterns were analysed in multiple samples from each tumour using flow cytometry and compared with clinical stage, tumour invasion, metastatic rate and survival. Eighty-five of 192 evaluable tumours (44%) were homogeneous concerning DNA ploidy (62% diploid, 38% aneuploid). Among 107 heterogeneous tumours a majority (79%) contained aneuploid as well as diploid cell clones. Homogeneously diploid tumours had a lower incidence of local tumour spread compared with tumours with aneuploid cell clones (P < or = 0.001), but the frequency of distant metastasis at time of diagnosis was similar. The presence of aneuploidy in at least one sample from a tumour was a significant adverse prognostic factor (P < 0.001), whereas the degree of heterogeneity had no influence on survival. The frequent heterogeneity demonstrated indicates that multiple samples must be investigated to evaluate properly the malignant character of renal cell carcinoma.

Clinical manifestations in patients with hereditary nonpolyposis colorectal cancer

The clinical manifestations of 1,042 Japanese patients with nonpolyposis colorectal cancer who underwent a resection between 1972 and 1992 at the National Kyushu Cancer Center were examined. Hereditary nonpolyposis colorectal cancer (HNPCC) was found in 39 (3.7%) patients. Some characteristic findings in HNPCC cases included early age of onset, a preponderance of right colon cancers, an increased frequency of colorectal cancers, and a favorable survival. Metachronous (postoperative) colorectal cancers developed significantly more often in cases with HNPCC than in those without (12.8% vs. 1.8%, P = 0.0001). Metachronous (postoperative) extracolonic cancers tended to develop more often in cases with HNPCC than in those without (10.2% vs. 3.5%, P = 0.053). In cases with HNPCC, the mean interval between the initial surgery and the diagnosis of the second cancer was 61 months (range; 12-153 months). These findings thus indicate the importance of routine and long-term follow-up to identify any second lesions, especially in patients with HNPCC.

Flow cytometric analysis of the DNA content in primary and metastatic lesions of colorectal cancer

We investigated and compared the DNA content between primary and metastatic lesions from 30 colorectal cancer cases. The findings were only diploid in 2 cases (6.7%) and only aneuploid in 18 cases (60.0%). On the whole, the DNA ploidy agreed in 20 cases (66.7%) between both lesions. In the 18 cases with only aneuploid tumors in both lesions, the DNA index tended to be larger in the metastatic lesions than in the primary lesions. In contrast, a variation in the DNA ploidy was observed in 10 cases (33.3%). These findings show that DNA ploidy tends to remain stable during metastasis in many cases of colorectal cancer, although the DNA index did tend to be larger in metastatic lesions than in primary lesions. The existence of intertumoral heterogeneity in the DNA ploidy also shows that specimens should be investigated from both lesions in order to obtain more accurate information on the tumor and its biological behavior.

Flow cytometric analysis of DNA heterogeneity in superficial carcinoma of the esophagus

BACKGROUND

There are few studies of flow cytometric analysis for DNA heterogeneity of patients with superficial carcinoma of the esophagus limited to the epithelium or superficially invading the lamina propria or submucosa.

METHODS

Flow cytometric analysis of cellular DNA content was performed on superficial carcinomas of the esophagus using paraffin embedded blocks of the surgically resected specimens from 56 patients. To evaluate the intratumoral DNA heterogeneity, a total of 141 samples of the 56 tumors were analyzed, depending upon the tumor size.

RESULTS

One or two of the samples was available from 18 of 19 patients with tumors 2 cm or less in greatest dimension, whereas more than three of the samples were available from 22 of 37 patients with tumors 2.1 cm or greater in dimension (P < 0.003). Of 56 tumors, 40 (71.4%) exhibited DNA aneuploidy; DNA heterogeneity was found in 26 tumors (46.4%). The remaining 16 tumors exhibited DNA diploidy. Two of the five tumors that were limited to the epithelium had DNA heterogeneity. The mean dimension of the tumors with DNA heterogeneity was significantly greater (5.8 +/- 2.8 cm) than those exhibiting DNA diploidy (2.3 +/- 1.1 cm) and DNA aneuploidy without heterogeneity (2.9 +/- 2.4 cm). Recurrences after esophagectomy were detected in 6 of the 56 patients; the DNA ploidy pattern of these six patients exhibited DNA heterogeneity.

CONCLUSION

The incidence of DNA heterogeneity increases as tumor size increases and is associated with an increased risk of tumor recurrence after esophagectomy in patients with superficial carcinoma of the esophagus.

Immunohistochemical analysis of p53 in colorectal cancer regarding clinicopathological correlation and prognostic significance

The overexpression of the tumor suppressor gene p53 was investigated immunohistochemically in 144 cases of primary colorectal cancer and in 8 cases with cancer in the corresponding metastatic lymph nodes. Abnormalities in p53 expression were found in 36 cases (25%) of the 144 primary cancer cases. In addition, p53-positive tumors were found to metastasize frequently to the lymph nodes, as compared to p53-negative tumors (61.1% vs. 41.7%, P = 0.0428). p53 staining was identical in 7 of 8 (87.5%) cases in primary and metastatic lesions. When the DNA content of the tumor was determined by flow cytometry, the DNA index (mean +/- SD) was significantly higher in p53-positive tumors than in p53-negative tumors (1.57 +/- 0.38 vs. 1.39 +/- 0.37, P = 0.012). Therefore, the immunohistochemical data of p53 in colorectal cancer may help in potentially predicting metastatic spread to the lymph nodes.

Achalasia-associated squamous cell carcinoma of the esophagus: flow-cytometric and histological evaluation

Although the risk of cancer is increased in patients with achalasia, biomarkers of an increased cancer risk have not been evaluated. In an esophagectomy specimen of a patient with achalasia-associated squamous cell carcinoma, normal mucosal and carcinomatous samples were systematically taken for flow cytometry and histology. The distribution of DNA aneuploidy and dysplasia was mapped within the resected specimen. Four of 10 tumor samples and 4 of 16 normal mucosal samples of the esophagus showed additional aneuploid stem lines. Gastric mucosa only showed diploid DNA histograms. S-phase fraction in normal esophageal samples (7.8% +/- 1.1%) was lower than in dysplastic and carcinomatous samples (8.8% +/- 2.4%; P = NS). Areas of mild to moderate dysplasia were detected in the esophageal mucosa adjacent to the neoplasm. This report shows the potential applicability of flow cytometry in the surveillance of patients with achalasia. However, prospective endoscopic studies with long follow-up periods are required before flow cytometric and histological parameters can be used as biomarkers of an increased cancer risk in achalasia.

Flow cytometric analysis of variations in the DNA content of superficial and deep layers in colorectal cancer

We investigated variations in the DNA content of multiple samples from both superficial and deep layers of tumors from 81 colorectal cancer cases. The findings were only diploid in 21 cases (25.9%) and only aneuploid in 49 cases (60.5%). On the whole, the DNA ploidy agreed in 70 cases (86.4%) between both layers. In the 49 cases with only aneuploid tumors in both layers, the DNA index (mean +/- SD) was 1.58 +/- 0.25 in the superficial layer and 1.59 +/- 0.25 in the deep layer, with the values being almost identical. In contrast, a variation in the DNA ploidy of 11 cases (13.6%) was observed. These findings show that DNA ploidy remains stable during tumor progression from the superficial into the deep layers in most cases of colorectal cancer. However, the existence of heterogeneity in the DNA ploidy also shows that several specimens should be collected from both layers before making a determination of DNA ploidy.

Analysis of gene amplification and overexpression in human esophageal-carcinoma cell lines

Gene amplification/overexpression was analyzed in 23 cell lines derived from human esophageal squamous-cell-carcinoma tissues by Southern and Northern hybridizations to c-myc, c-erbB, hst-1 and cyclin-D1 probes. Amplification of the c-myc gene was observed in 5 cell lines derived from well-differentiated carcinomas and all of them were accompanied by co-amplification of other examined oncogenes. The c-erbB gene was amplified in 3 cell lines. Co-amplification of hst-1 and cyclin D1, both of which are located in chromosome 11q13, was found in 9 cell lines. Without exception their amplification was simultaneous and the magnitudes were similar. Their amplification, but not their overexpression, was significantly correlated with poor prognosis in patients from whom the cell lines were established. While hst-1-gene expression was not detected, at least 1 of the genes analyzed was overexpressed in 20 cell lines vs. its expression in normal esophageal mucosal tissues. However, gene amplification was not necessarily accompanied by overexpression of the corresponding genes. Expression of the cyclin D1 gene, which has been assumed to be a target gene for 11q13 amplification, was not detected in one particular cell line with amplification of 11q13. These results suggest that the amplification/overexpression of more than I oncogene is involved in the carcinogenic process of esophageal carcinoma and that c-myc-gene amplification is associated with a well-differentiated subtype. There remains a possibility that key oncogenes other than cyclin D1 are involved in 11q13 amplification.

Esophageal cancer

Esophageal cancer is an important problem in the United States. It results in more deaths (over 10,000 annually) than rectal cancer. Furthermore, the incidence of esophageal adenocarcinoma is increasing at a rate faster than that of nearly any other cancer and the reasons for the increase are not well understood. A variety of tumor-suppressor genes (including p53, APC, DCC and Rb) and proto-oncogenes (including prad1, EGFR, c-erb-2 and TGF alpha) may be involved in the development and progression of esophageal cancer. Clinical prognostic factors include stage, Karnofsky performance status, sex, age, anatomic location of the tumor, and degree of weight loss. A new staging system based on depth of wall penetration and lymph node involvement correlates well with prognosis for patients undergoing esophagectomy. Newer staging procedures including endoscopic ultrasound as well as the use of minimally invasive surgery, such as thoracoscopy and laparoscopy, may allow accurate staging without esophagectomy. Surgical resection provides excellent palliation; however, the chance for cure with esophagectomy alone is only 10% to 20%. Adjuvant treatment with pre- or postesophagectomy radiation may improve local-regional control but does not improve survival. Nor has preoperative chemotherapy been shown to improve survival; however, it remains an active area of investigation. Multimodality therapy, namely, chemotherapy and radiation (chemoradiation), given concurrently prior to surgical resection shows promise, with one study indicating a 5-year survival of 34%. A complete pathologic response to chemoradiation correlates with improved survival. Chemoradiation has been shown to be superior to radiation as primary management of esophageal cancer. There has been no successfully completed randomized trial of surgery versus definitive radiation or chemoradiation. However, chemoradiation represents a reasonable alternative to esophagectomy in the primary management of squamous cell carcinoma of the esophagus and chemoradiation also appears to be effective in the treatment of patients with adenocarcinoma of the esophagus, offering significant palliation and a chance for long-term survival as well. Randomized studies of preoperative chemoradiation versus surgery or versus chemoradiation alone are needed. The treatment of advanced esophageal cancer must be directed toward palliation of symptoms. Newer endoscopic techniques, including the use of expansile metal stents, laser ablation, intraluminal high-dose rate brachytherapy, BICAP tumor probe, or photodynamic therapy, offer selected patients short-term palliation.(ABSTRACT TRUNCATED AT 400 WORDS)

Intratumoral DNA heterogeneity correlated with lymph node involvement and surgical staging in epithelial ovarian cancer by flow cytometry

BACKGROUND

Flow cytometry (FCM)-measured DNA content may be a predictor in the prognosis of ovarian cancer. Multiple specimens taken from the same ovarian tumor may show a variation in DNA content (i.e., intratumoral DNA heterogeneity). We measured the FCM DNA content of multiple specimens from the same tumor in ovarian cancer, and the relationship among DNA ploidy, intratumoral DNA heterogeneity, retroperitoneal lymph node involvement, and surgical staging was evaluated.

METHODS

Forty-one patients with primary epithelial ovarian cancer were included in the study. The FCM-measured DNA content of multiple fresh tumor specimens taken from different parts of the same ovarian tumor from each patient was measured. When aneuploidy was observed in at least one specimen from the same tumor, the tumor was defined as an aneuploid tumor. If there were two or more different aneuploid stem lines with a variation of DNA indices (differences of the DNA indices > 0.15) from the same tumor, the presence of intratumoral DNA heterogeneity was defined.

RESULTS

Diploid tumor was found in 8 (19.5%) of the 41 patients, and aneuploid tumor with intratumoral DNA heterogeneity was found in 20 (48.8%). None of the eight patients with diploid tumors demonstrated lymph node involvement. In contrast, lymph node involvement was found in 14 (70.0%) of 20 patients with intratumoral DNA heterogeneity. There was a significant different incidence of lymph node involvement between the groups with and without intratumoral DNA heterogeneity (P < 0.01). The incidence of intratumoral DNA heterogeneity significantly correlated with the International Federation of Gynecology and Obstetrics staging (P < 0.01), while that of aneuploid tumor did not.

CONCLUSIONS

Intratumoral DNA heterogeneity reflected a malignant potential for lymph node involvement and its progression in epithelial ovarian cancer.

Esophageal squamous cell carcinoma: pathology and prognosis

Between 1985 and 1992 a total of 403 patients with resected thoracic esophageal squamous cell carcinoma were evaluated histopathologically, and various pathologic findings related to survival were examined. Concerning depth of tumor invasion, 8 (2%) cases were pTis, 110 (27%) were pT1, 48 (12%) were pT2, 202 (50%) were pT3, and 35 (9%) were pT4. Lymphatic invasion was detected in 299 cases (74%), blood vessel invasion in 200 cases (49%), intramural metastasis in 45 (11%), and lymph node metastasis in 232 (58%). In pT1 carcinoma cases, 4% of mucosal carcinomas and 30% of submucosal carcinomas had lymph node metastasis. Tumors with deeper invasion had a higher incidence of lymph node metastasis: 74% of pT3 carcinomas and 83% of pT4 carcinomas. The sites of lymph node metastasis were divided into mediastinal, cervical, and abdominal fields; and rates of lymph node metastasis were 49%, 14%, and 41%, respectively. In all resected cases, the operative mortality rate was 3.2%, and the overall 5-year survival rate was 44.8%. The 5-year survival rate of patients with curative resection (R0 and R1) was 49.5%, whereas patients with palliative resection (R2) did not survive more than 3 years. There was no significant difference in survival relative to tumor location. In curatively resected cases, the significant prognostic factors by multivariate analysis were pT category, vascular invasion, lymph node metastasis, and intramural metastasis. Prognosis of lymph node-positive cases did not depend on the positive node site. Patients with only one positive node had a better prognosis, and those with six or more positive nodes had a poor prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Flow cytometric DNA ploidy and S-phase heterogeneity in advanced ovarian carcinoma

BACKGROUND

The prognostic significance of flow cytometric DNA ploidy and S-phase fraction (SPF) in ovarian cancer has been controversial. In the current study, the authors analyzed tumor heterogeneity in respect to DNA index DI and SPF.

METHODS

Flow cytometric variation in DI and SPF among representative fresh tumor material from the primary tumor, metastasis, and malignant effusions from the same patient was analyzed.

RESULTS

One hundred thirty-two samples from 47 patients were analyzed, and 119 samples from 42 patients were evaluable. Stable DI between different samples was found in 34 patients, whereas heterogeneity was found in 8 patients (19%). The metastases showed stable DNA content. The malignant effusion samples often lacked tumor cells. The representative ones were often DNA diploid. In 21% of the aneuploid samples, the SPF could not be analyzed. In 38% of the aneuploid samples, the stem line constituted less than 15% of measured nuclei. In these samples, a negative correlation between SPF and percentage of aneuploid cells was found, making SPF unreliable. Correct SPF measurement was thus possible in only 41% of the aneuploid samples, and in these tumors, SPF values varied considerably among different samples from the same patient, illustrated by a median SPF difference of 11% (range, 0-28%).

CONCLUSIONS

Tumor DI heterogeneity existed in 19% of tumors. SPF depended on the amount of aneuploid cells in case of small stem lines and varied considerably, making its use as a prognostic factor doubtful. To ensure that all tumor stem lines are represented, at least two biopsy specimens from any solid tumor should be analyzed.

Intraoperative radiotherapy for esophageal carcinoma--significance of IORT dose for the incidence of fatal tracheal complication

PURPOSE

The feasibility of intraoperative radiotherapy (IORT) combined with modified regional lymphatic dissection (plus esophagectomy) for advanced esophageal carcinoma was tested. The quality of life in the patients was expected to improve by modified surgery, securing a good local control by additional IORT.

METHODS AND MATERIALS

Total esophagectomy plus modified three-regional lymphatic dissection with upper mediastinal IORT followed by postoperative external beam irradiation was systematically given to 62 patients between August 1989 and June 1992. Sixty-five percent of the patients were age over 60, and 76% (47/62) of the patients were Stage III or IV by pTNM. Several techniques for the IORT were developed and used throughout this period, including a temporary collapse of the right lung by unilateral tracheal incubation (for the insertion of IORT applicator) and an in vivo dosimetry to know the appropriate range (energy) of electron beam. The method of surgical treatment, the dose of external beam irradiation were kept standardized, and only the dose of IORT was randomized either to 20 or 25 Gy. IORT-related complications and the pattern of failures were carefully monitored.

RESULTS

(a) Most prominent IORT-related complication was the late tracheal damage, which occurred 6 of 44 patients who were at risk for more than a year. (b) The incidence of IORT-induced tracheal damage was sharply dependent on the dose of IORT; 6 out of 21 patients who received single dose of 25 Gy, and none out of 33 who were given 20 Gy or less. (c) 2-year cause-specific survival and actuarial 2-year survival were 75.0 +/- 14.5% and 62.5 +/- 13.2%, respectively. No loco-regional recurrence has been detected at the time of analysis.

CONCLUSION

IORT in combination with modified total esophagectomy is an effective and safe method to obtain a local control in advanced esophageal carcinomas, if the dose of IORT does not exceed 20 Gy.

Heterogeneity in the nuclear DNA content of cells in carcinomas of the biliary tract and pancreas

BACKGROUND

The authors investigated the frequency of aneuploidy and heterogeneity in DNA ploidy within one tumor by multiple sampling.

METHODS

Using flow cytometry, the authors measured the nuclear DNA content of cells in fresh surgical specimens from 24 patients with carcinoma of the extrahepatic bile duct, 8 patients with carcinoma of the gallbladder, 5 patients with carcinoma of ampulla of Vater, and 14 patients with carcinoma of the pancreas.

RESULTS

The frequency of aneuploidy was 91.7%, 87.5%, 80.0%, and 85.7% in carcinoma of the extrahepatic bile duct, gallbladder, ampulla of Vater, and pancreas, respectively. The incidence of heterogeneity in DNA ploidy within a tumor was 79.2%, 87.5%, 80.0%, and 85.7% in carcinoma of the extrahepatic bile duct, gallbladder, ampulla of Vater, and pancreas, respectively. The DNA index ranged mostly from 1.0-2.0. Hypodiploid samples constituted 23.5% of the total, and only five (9.8%) had a DNA content above tetraploid. Many of the patients in which the DNA index was about 1.0 (including diploid cases) tended to be in the relatively early stages of the disease.

CONCLUSIONS

It is necessary to take several fresh samples from the same tumor to accurately measure the variations in nuclear DNA content. The authors suggest that three or four samples should be studied to determine aneuploidy and that DNA ploidy heterogeneity should be analyzed in five or six samples.

Lack of intratumoral heterogeneity in DNA ploidy pattern of hepatocellular carcinoma

BACKGROUND

From biological and clinical perspectives, it is important to clarify tumor heterogeneity. This study was aimed to investigate whether or not intratumoral heterogeneity of DNA ploidy pattern exists in hepatocellular carcinoma (HCC).

METHODS

Using fresh materials resected from 31 untreated patients, DNA ploidy was analyzed at different sites of the same HCC by means of flow cytometry. The tumor size ranged from 1.7 to 25.0 cm.

RESULTS

There was no case in which euploid and aneuploid HCCs coexisted in the same tumor. The DNA ploidy pattern was euploid in 15 and aneuploid in 16 instances. Of 15 euploid tumors, the areas analyzed were all diploid in 12 and tetraploid in 2 but diploid/tetraploid in 1. Among 16 aneuploid tumors, the DNA indices (DI) at different sites were similar in 9, but apparently, different aneuploid subclones coexisted in 7 cases. The incidence of DI heterogeneity in aneuploid HCCs was similar between small (< 5 cm) and large (> or = 5 cm) tumors; 3 of 7 (42.9%) versus 4 of 9 (44.4%).

CONCLUSIONS

It is assumed that euploid and aneuploid HCCs develop in their own ploidy pattern and that the evolution of aneuploid subpopulations from euploid HCC is rare, but new aneuploid subclones can evolve from aneuploid HCC due to increased instability of its karyotype.

Influence of preoperative radiotherapy on DNA ploidy in squamous cell carcinomas of the oesophagus

The influence of preoperative radiotherapy on the prevalence of DNA aneuploidy and the prognostic significance of tumour DNA ploidy was evaluated in 126 patients with squamous cell carcinoma of the oesophagus. Preoperative radiotherapy with 30 Gy was performed in 52 patients. DNA ploidy was analysed by flow cytometry on nuclei isolated from paraffin embedded tumour tissue. DNA aneuploidy was identified in 75 tumours (61%) and found to correlate significantly with tumour stage. The percentage of aneuploid carcinomas was significantly reduced by preoperative radiotherapy (surgery only group, 71%; radiotherapy group, 47%, p = 0.01). Although the median survival time was slightly better in the diploid than in the aneuploid group (11.3 and 8.0 months respectively), this difference was not statistically significant. A curative tumour resection was the most important prognostic factor. Preoperative radiotherapy did not prolong survival in oesophageal cancer.

Prognostic significance of flow cytometric analysis of DNA content in colorectal cancer: a prospective study

We prospectively analyzed the tumor DNA content by flow cytometry in 100 patients who underwent a curative resection for colorectal cancer between August 1989 and May 1992 in order to evaluate the prognostic significance of DNA ploidy and the DNA index (DI). Patients with aneuploid tumors were found to have a significantly shorter disease-free survival than those with diploid tumors (P = 0.014). In addition, patients who had tumors with a DI greater than 1.6 had a significantly shorter disease-free survival than those who had tumors with a DI of less than 1.6 (P = 0.0001). After stratification by stage, this association was only seen in Dukes' stage C disease (P = 0.0065). Cox's regression analysis demonstrated that the DI (below or above 1.6) rather than DNA ploidy was an important independent predictor of disease-free survival. These results suggest that the DI rather than DNA ploidy provides us with important prognostic information in patients undergoing curative surgery for colorectal cancer.

Gastric cancer with p53 overexpression has high potential for metastasising to lymph nodes

Overexpression of the tumour suppressor gene p53 was investigated immunohistochemically in 96 primary gastric carcinomas and 26 corresponding metastatic perigastric lymph nodes. Abnormalities in p53 expression were found in 52 (54%) of the 96 primary carcinomas. Tumours stained positively for p53 frequently metastasised to lymph nodes (the metastatic rate: 85%) compared to findings in those with negative p53 staining (64%, P < 0.05). Ninety-two percent (24/26) of the malignant cells in the lymph nodes stained positively for p53. When the DNA ploidy pattern of the tumour was determined by flow cytometry, the aneuploid tumours in p53 positive and negative groups accounted for 69% and 45%, respectively (P < 0.05). Proliferative activity of the tumour, as measured by Ki-67 labelling, was significantly higher (30.6 +/- 12.0%) in the p53 positive group than that (25.1 +/- 10.7%) in the p53 negative group (P < 0.05). Thus, gastric cancer with a mutant p53 has high proliferative activity and metastasis to lymph nodes will probably occur.

Clinical application of flow cytometry for DNA analysis of solid tumors

Recent developments of flow cytometry (FCM) technology which make multiple correlative biological measurements on normal and neoplastic cells is affecting areas of diagnostic pathology as well as research fields, and a general understanding of FCM techniques is essential for pathologists. Today, FCM DNA measurements of tumors also becomes routine in the clinical and/or pathological laboratory for aid in cancer diagnosis and cancer treatment. It can also contribute to diagnosis of tumors as a supplemental method to conventional histopathology, and DNA ploidy and the percentage of S-phase fraction are considered as complementary prognostic parameters independent of the stage of disease. This article reviews clinical applications of flow cytometry focusing on the DNA measurements of solid tumors, and related practical issues, such as the methodology for nuclear DNA measurement, interpretation of DNA histograms and the relationship of DNA ploidy and S-phase fraction to clinical and pathological features of human solid tumors.