Variability in DNA measurements in multiple tumor samples of human colonic carcinoma

Investigation of radiomics based intra-patient inter-tumor heterogeneity and the impact of tumor subsampling strategies

While radiomics analysis has been applied for localized cancer disease, its application to the metastatic setting involves a non-exhaustive lesion subsampling strategy which may sidestep the intrapatient tumoral heterogeneity, hindering the reproducibility and the therapeutic response performance. Our aim was to evaluate if radiomics features can capture intertumoral intrapatient heterogeneity, and the impact of tumor subsampling on the computed heterogeneity. To this end, We delineated and extracted radiomics features of all visible tumors from single acquisition pre-treatment computed tomography of patients with metastatic lung cancer (cohort L) and confirmed our results on a larger cohort of patients with metastatic melanoma (cohort M). To quantify the captured heterogeneity, the absolute coefficient of variation (CV) of each radiomics index was calculated at the patient-level and a sensitivity analysis was performed using only a subset of all extracted features robust to the segmentation step. The extent of information loss by six commonly used tumor sampling strategies was then assessed. A total of 602 lesions were segmented from 43 patients (median age 57, 4.9% female). All robust radiomics indexes exhibited at least 20% of variation with significant heterogeneity both in heavily and oligo metastasized patients, and also at the organ level. None of the segmentation subsampling strategies were able to recover the true tumoral heterogeneity obtained by exhaustive tumor sampling. Image-based inter-tumor intra-patient heterogeneity can be successfully grasped by radiomics analyses. Failing to take into account this kind of heterogeneity will lead to inconsistent predictive algorithms. Guidelines to standardize the tumor sampling step and/or AI-driven tools to alleviate the segmentation effort are required.

Targeting stemness of cancer stem cells to fight colorectal cancers

Cancer initiating/ stem cells (CSCs) undergo self-renewal and differentiation that contributes to tumor initiation, recurrence and metastasis in colorectal cancer (CRC). Targeting of colorectal cancer stem cells (CCSCs) holds significant promise in eradicating cancer cells and ultimately curing patients with cancer. In this review, we will introduce the current progress of CCSC studies, including the specific surface markers of CCSCs, the intrinsic signaling pathways that regulate the stemness and differentiation characteristics of CCSCs, and the tumor organoid model for CCSC research. We will focus on how these studies will lead to the progress in targeting specific surface markers or signaling pathways on CCSCs by monoclonal antibodies, or by natural or synthetic compounds, or by immunotherapy. As CSCs are highly heterogeneous and plastic, we suggest that combinatory approaches that target the stemness network may represent an important strategy for eradicating cancers.

DNA content in human colon cancer and non-neoplastic adjacent mucosa

DNA content was determined by flow cytometry in a series of 51 paired fresh tissue samples of primary colorectal carcinomas and the respective non-neoplastic adjacent mucosa in order to assess the relationship between DNA ploidy and the most commonly used prognostic factors. Aneuploidy was observed in 70.6% of the tumors and more than one aneuploid peak was present in 3.9%. Aneuploid tumor frequency was higher in left (93.3%) and right colon (64.7%) cancers than in rectal carcinomas (60.0%), and multiple aneuploid clones were detected more frequently in men than in women and in patients with advanced disease (Dukes stage D). Non-neoplastic mucosa adjacent to aneuploid tumors showed aneuploidy in 4 out of 51 samples (7.8%). The mucosa adjacent to diploid cancers had only diploid characteristics. Polidy did not correlate with histological abnormalities.

These findings suggest that DNA content as determined by flow cytometry needs further study with adequate follow-up to evaluate possible correlations with relapse-free and overall survival. Furthermore the aneuploidy of non-neoplastic mucosa provides evidence for a field defect in mucosa adjacent to colorectal cancer and supports the concept that this alteration may be of influence on carcinogenesis.

CD51 correlates with the TGF-beta pathway and is a functional marker for colorectal cancer stem cells

Colorectal cancer (CRC) is one of the top three most prevalent and deadly cancers. A cancer stem cell (CSC) sub-population that is characterized by the abilities of tumor initiation, self-renewal, metastasis and resistance to chemotherapy can suggest new therapeutic targets. However, no such sub-population has been conclusively identified for CRC, and we lack any marker to identify cells with all of the above characteristics. Here, we report that CD51⁺ CRC cells displayed greater sphere-forming and tumorigenic capacities, increased migratory and invasive potentials, and enhanced chemoresistance compared with CD51^- CRC cells. CD51 knockdown reduced the side population, sphere formation, cell motility and inhibited tumor incidence and metastasis in an in vivo tumor model. Furthermore, CD51 could bind transforming growth factor beta (TGF-β) receptors, and that it upregulated TGF-β/Smad signaling. These results indicate that CD51 is a novel functional marker for colorectal CSCs which may provide an therapeutic target for the efficient elimination of colorectal CSCs.

Colorectal cancer stem cells: from the crypt to the clinic

Since their first discovery, investigations of colorectal cancer stem cells (CSCs) have revealed some unexpected properties, including a high degree of heterogeneity and plasticity. By exploiting a combination of genetic, epigenetic, and microenvironmental factors, colorectal CSCs metastasize, resist chemotherapy, and continually adapt to a changing microenvironment, representing a formidable challenge to cancer eradication. Here, we review the current understanding of colorectal CSCs, including their origin, relationship to stem cells of the intestine, phenotypic characterization, and underlying regulatory mechanisms. We also discuss limitations to current preclinical models of colorectal cancer and how understanding CSC plasticity can improve the development of clinical strategies.

Prognostic value of ki-67 in breast carcinoma: tissue microarray method versus whole section analysis- potentials and pitfalls

In our study we have compared the prognostic value of two distinct methods of immunohistochemical Ki-67 determination, tissue microarray (TMA) and classical whole section analysis. "Cut-off" values were used according to the 2009 St. Gallen Consensus. Tissue specimens were obtained from a consecutive retrospective series of 215 female patients with primary invasive tumours. Two hundred and thirteen patients were included in the study. Data on Ki-67 was collected by both tissue microarray (TMA) and whole section analysis. Follow up data on overall (OS) and disease-free survival (DFS) were collected. Median follow-up was 95 months (range from 7.8 through 107 months). Mutual correlation of two Ki-67 determination methods was non-significant (Person's r = 0.13417; p = 0.0528). There was statistically significant association of whole section Ki-67 expression with histological and nuclear grade, progesterone receptor and HER2/neu status. The expression of Ki-67 protein in TMAs correlated only with histological and nuclear grade, but not with other traditional clinicopathological factors. Statistically significant differences in DFS (p = 0.0156) and OS (p = 0.0028) were confirmed between subgroups with low and high whole section Ki-67 expression. When subgroups with high and intermediate expression were compared, significant difference was found in DFS (p = 0.0272), but not in OS (p = 0.0624). On the other hand, there was no statistically significant difference either in DFS, or in OS, according to the expression of Ki-67 in TMAs (p = 0.6529; p = 0.7883; p = 0.7966 for DFS, and p = 0.8917; p = 0.6448; p = 0.4323 for OS, respectively). In our study, classical whole section was superior to TMA analysis in terms of prognosis and clinicopathological correlation. Our results indicate that the method used may have impact on prognostic significance of Ki-67. Further studies are needed, covering a greater number of patients and including a precisely defined stage and treatment patient cohorts, in order to solve controversies in Ki-67 assessment methodology.

Expression of P53 Protein and Dna Flow Cytometry in Gastric Adenocarcinoma: Implications in Patients Treated with Adjuvant Etoposide, Adriamycin and Cisplatin

Aims and background

We evaluated the prognostic value of p53 protein, DNA content and S-phase fraction in patients with adenocarcinoma of the stomach or the gastroesophageal junction treated with adjuvant etoposide, doxorubicin and cisplatin.

Methods and study design

Thirty-five consecutive patients with stage II or III gastric or gastroesophagial junction adenocarcinoma treated with at least two cycles of adjuvant etoposide, doxorubicin and cisplatin after curative gastric resection were included. The expression of p53 protein was determined by immunohistochemistry and DNA content by flow cytometry. The presence of p53 expression and DNA content was compared with clinicopathological features.

Results

Median age was 54 years (range, 31–71). P53 expression was detected in 42.9% (15 of 35) of gastric cancer tissues of the patients. Aneuploidy was observed in 31.4% of patients, and S-phase fraction was more than 10% in 22.9%. P53 immunoreactivity (33.3% vs 47.8%) was more common in advanced disease. There was no association among p53 immunoreactivity, DNA content and S-phase fraction. We also found no significant relationship between p53 immunoreactivity, DNA content, S-phase fraction or other clinicopathological parameters. In univariate analysis, the involvement of lymph nodes was a significant predictor of a poor outcome (P = 0.001). Also, p53-positive patients had a poor survival close to the level of significance (P = 0.051). Likewise, p53 immunoreactivity (P = 0.0071), in addition to lymph node involvement (P = 0.0016), were the independent prognostic factors in multivariate analysis.

Conclusions

This trial supports the results of previous reports that p53 immunoreactivity is a prognostic factor for patients with adenocarcinoma of stomach or gastroesophageal junction treated with adjuvant chemotherapy.

DNA ploidy in colorectal cancer, heterogeneity within and between tumors and relation to survival

Flow cytometry was used to study the incidence of aneuploidy and to determine the significance of multiple sampling from colorectal tumors. DNA ploidy pattern has been proposed as a supplementary prognostic marker, but discrepancies in findings are major. DNA clonal heterogeneity, defined as two or more DNA aneuploid stemlines in the same tumor, is well established. However, most studies have been based on only one biopsy from each tumor. In our study multiple biopsies were taken from 163 patients (88 males and 75 females) electively operated for colorectal cancer. Tumor cells were harvested by fine needle aspiration from fresh frozen biopsies sampled at different sites of each tumor. DNA aneuploidy was detected in tumors from 145 patients (89%), and 18 patients (11%) had a solitary DNA diploid cell population. In a 79 month follow-up period 105 patients had died. Statistical analysis showed that distinction between diploidy and aneuploidy did not predict survival. However, grouping subpopulations into DNA diploid plus near diploid (DNA index (DI) 0. 97-1.15), DNA aneuploid with all aneuploid subpopulations in the interval 1.15-2.06, and DNA aneuploid with subpopulations with DI < 0.97 and/or DI > 2.06, showed a significant difference in survival in a Cox multivariate analysis including Dukes' stage P = 0.049 comparing the second group to the first and P = 0.01 comparing the third group to the first. In 21 (13%) patients only one subpopulation was found, 57 (35%) had two, 44 (27%) had three, and 41 (25%) had four or more different subpopulations. The association of DNA ploidy to survival is shown to be dependent on the number of biopsies analysed.

Intratumoral heterogeneity of DNA content in renal cell carcinoma and its prognostic significance

BACKGROUND

A multiple sampling study was performed on 124 specimens of renal cell carcinomas to analyze the consistency and reliability of DNA measurements. The authors investigated intratumoral DNA heterogeneity and its role as a adverse prognostic factor for disease progression.

METHODS

DNA content was analyzed by flow cytometry on three different samples of the same tumor. The Cronbach alpha coefficient was used to assess the reliability and a Cox proportional hazards model was used to test the effect of DNA ploidy heterogeneity on time of disease progression.

RESULTS

The agreement among the DNA ploidy samples was high. The number of aneuploid findings increased significantly with the number of samples analyzed. The presence of non-diploid cell populations was a significant adverse predictive value for disease progression. However, the authors were unable to demonstrate that intratumoral heterogeneity DNA content had any influence on the biological behavior of the tumor.

CONCLUSIONS

Determination of DNA ploidy based on single samples may be inaccurate. Spatial variation in DNA ploidy is a feature of renal cell carcinoma; however, its biologic significance remains to be demonstrated.

Advances and new concepts in oral and maxillofacial pathology

New techniques in surgical pathology at the cellular and molecular levels offer the clinician help in determining modalities of treatment of specific diseases. In addition to routine staining, adjunctive tests such as immunohistochemical analysis, and the various methods of evaluating nucleic acid have helped make this possible. The efficacy of fine-needle aspiration biopsy has been enhanced by these diagnostic aids that enable the assessment of information from small amounts of tissue.

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.

Intratumoral heterogeneity in primary breast carcinoma: study of concurrent parameters

BACKGROUND AND OBJECTIVE

Intratumoral heterogeneity for prognostic factors (ploidy, proliferation, hormone receptor positivity) has been demonstrated in primary breast carcinoma by both flow cytometric and image analysis methods. Previously, heterogeneity in tumors had been demonstrated for only singular parameters. Our objective, using maps of tumors in which discrete regions can be analyzed simultaneously for DNA index (DI) and proliferative activity, was to demonstrate heterogeneity with respect to two parameters and to determine whether any interparametric relationships existed.

METHODS

We analyzed 25 cases of archived, paraffin-embedded breast carcinoma (ductal) for Feulgen stain DNA analysis and MIB-1 immunohistochemistry using the CAS 200 Image Cytometer. For each tumor, four discrete regions were analyzed including tumor-host tissue interface sectors.

RESULTS

Of 25 cases, 19 (76%) were homogeneously diploid or near-diploid aneuploid, and 6 (24%) were heterogeneous. Within the heterogeneous group, all cases had at least one diploid and one or more aneuploid populations from separate discrete regions. Five of six DI heterogeneous tumors displayed diploid values for the overall measurements of the respective tumors, based on analysis of 200 or more nuclei. Eight of 25 cases (32%) showed significant measurable variation for MIB-1 proliferative activity in various sectors of tumor. All the MIB-1 heterogeneous tumors, with one exception, were homogeneously diploid.

CONCLUSIONS

These findings demonstrate that (1) heterogeneity is present with respect to DI and proliferative activity in breast carcinoma and is relatively common, (2) tumors homogeneous for one parameter may be heterogeneous for another, and (3) heterogeneity for proliferative activity is more common in homogeneously diploid tumors than in heterogeneous/aneuploid tumors.

DNA heterogeneity determined by flow cytometry in prostatic adenocarcinoma--necessitating multiple site analysis

Although DNA ploidy analysis of prostate cancer is generally associated with grade, stage, clinical outcome, and responsiveness to androgen therapy, one possible reason cited for contrary reports may be tumor heterogeneity. A preliminary report using flow cytometric analysis of punch biopsies demonstrated DNA heterogeneity in five of nine patients. We evaluated 75 patients by cutting whole mounts of formalin fixed prostatectomy tissue every 0.6 cm. All malignant areas and a selected normal area were circumscribed, excised, remounted, and 1-3 50 mu thick sections removed. The nuclei were extracted by a Hedley technique and the DNA stained with propidium iodide. Each whole mount had an average of 1 distinct malignant area (range of 1-6 areas per whole mount block). Nuclei were analyzed on a Becton Dickinson (San Jose, CA) FACScan flow cytometer equipped with RFIT DNA software program. After excluding histograms with CVs > 8.0% and/or "suspicious" diploid histograms having a right "shoulder," 75 or 87 patients still had > or = 2 malignant sites available for analysis (average 4, range 2-9 malignant sites/patient). The 322 histograms had an average CV of 4.4%. Thirty of 75 patients (40%) showed DNA heterogeneity in multiple samples taken from the same prostate. There were 37 prostates with only diploid (D), 1 with only tetraploid (T), 7 with only aneuploid (A), 20 with D plus A, 7 with D plus T, 2 with D plus T plus A, and 1 with a D plus suspected hypodiploid DNA content. Exclusion of the tetraploid and "near diploid aneuploid" cases still resulted in 16% (12/75) of the patients having a diploid versus aneuploid DNA content heterogeneity. Because 40% of the prostates contained a different ploidy depending on which area was sampled, this report suggests multiple sites of malignancy must be analyzed to more accurately assess the ploidy status of prostatic adenocarcinoma.

Flow cytometric analysis of the DNA content in colorectal adenomas with focal cancers

BACKGROUND & AIMS

Variable results have been reported on the nuclear DNA content of colorectal polyps. The significance of DNA aneuploidy in the malignant transformation of colorectal polyps was evaluated.

METHODS

We analyzed by flow cytometry the nuclear DNA content of freshly frozen samples of 50 colorectal adenomas with or without focal cancers, analyzing separately the adenomatous and cancerous regions of the polyps.

RESULTS

In the adenomatous regions of the 50 polyps, the DNA was diploid in 43 and aneuploid in 7; the adenomas with DNA aneuploidy in the adenomatous regions were more frequently accompanied by focal cancers than were the DNA-diploid adenomas (P < 0.01). In 60% of the polyps with DNA aneuploidy in the cancerous regions, the DNA was also aneuploid in the adenomatous region and had similar DNA indices; this result suggests that the DNA aneuploidy had already occurred during the adenomatous stage, which lends support to the concept of the adenoma-carcinoma sequence. DNA aneuploidy in the adenomatous region was significantly correlated with the size of colorectal polyps (P < 0.05).

CONCLUSIONS

DNA aneuploidy may be an important indicator for the early diagnosis of malignant transformation of colorectal polyps.

Debris compensation of DNA histograms and its effect on S-phase analysis

Debris compensation is an important variable affecting S-phase fraction (SPF) analysis in flow cytometric DNA histograms. The SPF was estimated in fresh frozen breast carcinomas using the following four debris subtraction algorithms: modeling debris as an exponential curve (EXP); the incorporation of nuclei cut a single time into the exponential moel (EXP-SC); the random cutting of nuclei into multiple pieces of varying sizes (MC); and a combination of both nuclear cutting models (SC-MC). Comparison of SPF estimates indicated that the various debris subtraction models yielded differences in SPF, with SPF values obtained using the exponential model having considerable variation compared to SPF estimates from histograms where debris was modeled by algorithms based on nuclear slicing and fragmentation. However, SPF estimates could be affected by initial placement of the nuclear debris boundaries, the coefficient of variation of the G0/1 peak, and the relative amount of debris. Using the ratio of the height of the G0/1 peak to the height of the debris between the chicken red blood cells (CRBC) and G0/1 peaks as an objective measurement of nuclear debris, debris compensation was necessary in diploid DNA histograms where this ratio was as low as 1.5%. Taken in the context of SPF prognostic cutoff levels, variation in debris models and boundaries can change the classification of cases with borderline SPF levels into the poor prognostic high SPF categories, thereby making the comparison of SPF values derived from different studies difficult.

Correlation of DNA content between endoscopic biopsy and surgically resected specimens in gastric and colorectal cancer

To investigate DNA heterogeneity and the consistency of DNA content between endoscopic biopsy and the corresponding resected specimens, the DNA content of 749 different samples from 30 gastric and 30 colorectal cancers was analyzed and the results were compared with those obtained from endoscopic biopsy specimens. The incidence of DNA heterogeneity was 33% in patients with gastric cancer and 40% in those with colorectal cancer. Most of the cases of heterogeneity were caused by differences in DNA indices in aneuploidy. The consistency of DNA ploidy pattern between endoscopic biopsies and the corresponding resected specimens was 100% in both gastric and colorectal cancer, while the consistency in the DNA index of aneuploid tumors was approximately 90%. From these results, it seems possible that analysis of the DNA content of a biopsy specimen could provide an adequate measure of the DNA content of the corresponding resected specimen.

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.

Karyotypic characterization of colorectal adenocarcinomas

Cytogenetic analysis of short-term cultures from 52 primary colorectal adenocarcinomas revealed clonal chromosome aberrations in 45 tumors, whereas the remaining 7 had a normal karyotype. More than 1 abnormal clone was detected in 26 tumors; in 18 of them, the clones were cytogenetically unrelated. The modal chromosome number was near-diploid in 32 tumors and near-triploid to near-tetraploid in 13. Only numerical aberrations were identified in 13 carcinomas, only structural aberrations in 3, and 29 had both numerical and structural changes. The most common numerical abnormalities were, in order of decreasing frequency, gains of chromosomes 7, 13, 20, and Y and losses of chromosomes 18, Y, 14, and 15. The structural changes most often affected chromosomes 1, 17, 8, 7, and 13. The most frequently rearranged chromosome bands were, in order of decreasing frequency, 13q10, 17p10, 1p22, 8q10, 17p11, 7q11, 1p33, 7p22, 7q32, 12q24, 16p13, and 19p13. Frequently recurring aberrations affecting these bands were del(1)(p22), i(8)(q10), i(13)(q10), and add(17)(p11-13). The most common partial gains were from chromosome arms 8q, 13q, and 17q and the most common partial losses from chromosome arms 1p, 8p, 13p, and 17p. A correlation analysis between the karyotype and the clinicopathologic features in our total material, which consists of altogether 153 colorectal carcinomas, including 116 with an abnormal karyotype, showed a statistically significant association (P < 0.05) between the karyotype and tumor grade and site. Carcinomas with structural chromosome rearrangements were often poorly differentiated; well and moderately differentiated tumors often had only numerical aberrations or normal karyotypes. Abnormal karyotypes were more common in rectal carcinomas than in carcinomas situated higher up. Near-triploid to near-tetraploid karyotypes were more than twice as frequent in tumors of the distal colon as in those of the proximal colon and rectum. The cytogenetic data indicate that carcinomas located in the proximal colon and rectum, which often are near-diploid with simple numerical changes and cytogenetically unrelated clones, probably arise through different mechanisms than do tumors located in the distal colon, which more often have complex near-triploid to near-tetraploid karyotypes.

Intratumoral DNA heterogeneity of small hepatocellular carcinoma

BACKGROUND

Intratumoral DNA heterogeneity provides important information regarding biologic and clinical behavior. The purpose of this study was to evaluate the incidence of DNA heterogeneity in small hepatocellular carcinoma (HCC) nodules.

METHODS

The DNA content of 28 surgically resected small HCC nodules (< or = 3.0 cm) was measured using flow cytometry of fresh or frozen samples taken from different parts of each nodule with reference to the macroscopic features.

RESULTS

Of the 28 small HCC nodules, 14 (50.0%) had only DNA diploid stemline characteristics. Five nodules (17.9%) manifested DNA diploid and DNA aneuploidy within the same tumor. Of the remaining nine nodules (32.1%) that showed only DNA aneuploidy, two contained tumor tissues with apparently different DNA content. Thus, DNA heterogeneity was found in 7 (25.0%) of 28 nodules. DNA heterogeneity correlated well with macroscopic histologic features. All four early HCC were composed of only DNA diploid cells, whereas three of six nodule-in-nodule lesions were composed of DNA heterogeneous cells, in which the inner obviously cancerous nodule showed DNA aneuploidy and the outer well differentiated HCC portion demonstrated DNA diploid. Four of 18 overt HCC nodules showed DNA heterogeneity; 2 of these 4 nodules showed both diploid and aneuploid peaks, and the other 2 two showed different aneuploid peaks within the same nodule.

CONCLUSIONS

DNA heterogeneity correlating with macroscopic features is found frequently even in small HCC nodules. Therefore, multiple sampling based on macroscopic features is required for the accurate assessment of DNA ploidy, particularly when the information about DNA ploidy is used as a prognostic indicator.

Prognostic predictors in colorectal cancer

PURPOSE

Better prognostic predictors in colorectal cancer than the Dukes stage are necessary for individualized therapy and follow-up.

METHODS

Survival among 212 patients operated on for colorectal cancer was examined regarding various clinical, histopathologic, cellular, and serologic tumor characteristics.

RESULTS

Beside the Dukes stage, which was the most powerful variable, the erythrocyte sedimentation rate, leukocyte blood count, alkaline phosphatase, aspartate aminotransferase, six different serum tumor markers, number of small blood vessels, and age were found to be significantly associated with survival. The leukocyte blood count, alkaline phosphatase, and aspartate aminotransferase retained their significance in a multivariate model including tumor differentiation, local tumor stage, and age. Inclusion of tissue polypeptide antigen, the most powerful tumor marker in the multivariate model, showed that only the tumor stage, tissue polypeptide antigen, and age were statistically significantly correlated to survival. This was valid both for the group of patients considered as potentially curable and for those who potentially have been cured (Dukes Stages A-C).

CONCLUSIONS

A great number of prognostic predictors failed to discard Dukes stage as the best one. One serum tumor marker, tissue polypeptide antigen, contains independent additional prognostic information.

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.

DNA or cell kinetics flow cytometry analysis of 33 small gastrointestinal cancers treated by photodynamic therapy

BACKGROUND

Photodynamic therapy (PDT) mediated by hematoporphyrin derivative (HPD) is a new treatment for cancers of small volume undergoing Phase II or III clinical trials in various medical fields. However, there is a lack of prognostic criteria of efficacy as in other cancer treatment.

METHODS

Cell DNA content or cell kinetics throughout the cell cycle were analyzed by flow cytometry and propidium iodide staining before and after HPD-PDT in 33 patients with Tis or T1 cancers of the gastrointestinal tract. The authors compared results in near-diploid cancers with those obtained in normal corresponding tissue.

RESULTS

Complete local tumor destruction and negative histologic findings (complete response [CR]) were observed in 17 of 33 patients during a period averaging 15.7 months. Flow cytometry DNA analysis was feasible in 32 patients. Aneuploidy, found in 15 of the 32 indicated a poor prognosis because 5 of 15 patients with aneuploid tumors were classified as having CR, compared with 12 of 17 patients with near-diploid tumors (P < 0.05). Changes in ploidy after PDT in 11 patients consisted of a reduction in the number of aneuploid peaks in 8 patients and the appearance of one aneuploid peak in 3 patients. Percentages of cells in SG2M phase in near-diploid tumors differed from those observed in control subjects for adenocarcinomas, and there was no significant decrease after HPD-PDT. There was no correlation between the decrease of SG2M cells and the response to HPD-PDT.

CONCLUSION

Results obtained with PDT in this series of patients confirm previously published findings. Changes occurring in the ploidy of PDT-treated patients demonstrate that PDT acts directly on cancer cells in humans and not only on tumor vasculature. However, response to PDT varies from one cell population to another. The appearance of aneuploid populations after PDT suggests that destruction of sensitive cell populations allows the growth of aneuploid clones that initially are not detectable by flow cytometry.

Comparison of flow cytometry for DNA content and brush cytology for detection of malignancy in pancreaticobiliary strictures

Brush cytology for the routine microscopic examination of malignant pancreaticobiliary strictures has been shown to have a high degree of specificity but a sensitivity of less than 75%. We wanted to determine whether flow cytometric analysis for DNA content could increase the sensitivity of routine cytology in brushings from these strictures, especially in those patients with atypical cells noted by brush cytology but no definite tumor cells. Fifty-one sets of brushings were obtained from 48 patients in whom ERCP revealed pancreaticobiliary strictures. Specimens were obtained for both routine cytology and flow cytometry. Both studies were shown to have a sensitivity of 42% in diagnosing malignant strictures. The specificity was 92% for routine cytology and 77% for flow cytometry, with false-positive results obtained in one patient by the former technique and in three by the latter. When the studies were combined, so that the presence of either tumor cells or abnormal DNA content was diagnostic of malignancy, the sensitivity rose to 63%. However, the specificity fell to 69%. Routine cytology identified atypical cells in 13 patients with malignant strictures (39%). Flow cytometry identified abnormal DNA content in only six of these patients with atypical cytological specimens (46%). Although flow cytometry succeeded in identifying eight additional strictures as malignant, it was associated with a greater false-positive rate than was routine cytology. For patients with pancreatic carcinoma, increased survival was noted in those with a diploid cell population (mean, 8.9 months) as revealed by flow cytometry compared to those with aneuploid brushings (mean, 3.0 months). We conclude that the addition of flow cytometry for DNA content to routine cytology increases the diagnostic yield of brushings from pancreaticobiliary strictures. However, these results need to be interpreted together with the patient's history, ERCP, and other clinical findings in order to minimize false-positive results.

Application of the crypt-isolation technique to flow-cytometric analysis of DNA content in colorectal neoplasms

BACKGROUND/AIMS

Conventional flow-cytometric analysis of colorectal tumor DNA content includes both tumor and stromal cell DNA. To improve the method, we evaluated the DNA content of purified epithelial cells using the crypt-isolation technique.

METHODS

Normal and neoplastic crypts were isolated from fresh resected colorectum nonenzymatically. Isolated crypts were digested into single nuclei suspensions and examined by flow cytometry (FCM). Internal controls from normal crypts were used to define diploidy. The neoplastic nuclei in the same individual and mixtures of both normal and neoplastic nuclei in various ratios were analyzed.

RESULTS

Tumors having both diploid and aneuploid stemlines were found more frequently than that reported using conventional FCM. Near-diploid DNA stemlines with DNA indices ranging between 0.90 and 1.10 were detectable. The cases of advanced cancer in which the DNA index was between 0.90 and 0.95 were associated significantly with Dukes' stage C.

CONCLUSIONS

This is the first reported analysis of the DNA content of "pure" neoplastic colorectal epithelia using FCM. Multiploid and near-diploid stemlines were more accurately analyzed than that using conventional FCM.

Flow cytometric DNA analyses of frozen samples from children's solid tumors

Cell ploidy and proliferative activity may be useful to clinicians in treating children with solid tumors. Frozen specimens from children with malignant solid tumors were tested at the time of diagnosis for ploidy and proliferative activity. The flow cytometric DNA histograms were examined to assess the sensitivity of the tumor cell preparation and staining method. All the frozen tumors received (n = 58), from children aged 1 mth to 17 yrs, were analyzed and included in this study. The more common tumors were neuroblastomas (n = 21) and Wilms' tumors (n = 16). The majority of tumors (91%) exhibited a diploid peak from the significant proportion of stromal/epithelial cells in the tumor specimen. The tightness of the diploid G0G1 peaks as measured by their coefficient of variations (CV) produced a mean CV of 2.43% +/- SD 0.62, range 1.3% to 4.6%. The G0G1 CVs from the aneuploid peaks had a mean of 2.34% +/- SD 0.68 with the range 0.5% to 3.7%. There was, however, a proportion of tumors (9%) which showed no normal "diploid" peak on the histogram. These tumor cell suspensions had insignificant numbers of diploid cells. Unless the position of the diploid peak could be identified on the DNA histogram the ploidy result from such tumors would be incorrect. Reference diploid cells can be added to cell suspensions prepared from frozen tumors in order to identify the position of the G0G1 peak. Reference diploid cells cannot be added to single cell preparations from paraffin embedded specimens, therefore making it impossible to define the diploid peak position in these tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA mapping of colorectal neoplasms: a flow cytometric study of DNA abnormalities and proliferation

BACKGROUND

There is some evidence that neoplastic development and progression evolve through a multistep process associated with hyperproliferation and genetic alterations. Therefore, changes of proliferation and of cellular DNA content within the adenoma-carcinoma sequence were studied.

METHODS

Using a "mapping" procedure, 12 adenomas and 18 carcinomas were analyzed flow cytometrically and histologically. In addition, normal mucosa adjacent to and distant from the tumors was assessed in the same way.

RESULTS

Of 59 adenomatous fractions, 35.6% (n = 21) were aneuploid, whereas the incidence of aneuploidy was 63.5% (54/85) in the carcinomatous sites. Additional tetraploidies were identified in 5 (8.5%) and 13 (15.3%) adenomatous and carcinomatous samples, respectively. Cell proliferation, as determined by the percentage of S-phase cells, was significantly (P < 0.001) higher in the carcinomatous specimens (14.8% +/- 0.8%; mean +/- SEM) than in the adenomatous ones (8.1% +/- 0.7%). It decreased to normal mucosa adjacent to (5.1% +/- 0.5%) and distant (5.3% +/- 0.6%) from the neoplasms. DNA mapping of the tumors revealed both distinct regions and extended areas of aneuploidy and tetraploidy. There is evidence from the mapping data that aneuploid populations arise at a single focus of the adenoma and expand over large areas before a subpopulation of cells acquires the capacity of invasion.

CONCLUSIONS

These data showing consecutive DNA content abnormalities within the colorectal adenoma-carcinoma sequence provide support for genomic instability and clonal evolution as important events of tumorigenesis and progression.

Cytogenetic analysis of 52 colorectal carcinomas--non-random aberration pattern and correlation with pathologic parameters

Cytogenetic analysis of short-term cultures from 52 colorectal carcinomas revealed a normal karyotype in 13 and clonal chromosome aberrations in 39 tumors. In the abnormal group, 13 tumors had simple numerical changes only, whereas 26 had at least one structural rearrangement with or without concomitant numerical changes. The most common numerical abnormalities were, in order of decreasing frequency, +7, -18, -Y, +8, +13 and -14. The most common structural rearrangements affected, again in order of decreasing frequency, chromosomes 8, 1, 6, 7, 17, 3, 11, 13, 14, 16, 2 and 10. The chromosome bands most frequently involved in the structural changes were 8q10, 17p11, 11q13, 8p11, 6q21, 7p15, 7q36, 12q13, 13q10, and 16q13. The most frequent genomic imbalances brought about by the structural rearrangements were losses from chromosome arms 8p, 1p, 6q, 17p, 7p, and 16q, as well as gains of 7q, 8q, 13q, and 11q. A statistically significant (p < 0.05) correlation between the karyotypic pattern and tumor grade was found, with the poorly differentiated carcinomas generally having more massive chromosomal abnormalities.

Intra-tumoral heterogeneity of tumour potential doubling times (Tpot) in colorectal cancer

Intra-tumoural heterogeneity of proliferation has been assessed by taking multiple biopsies from 30 colorectal cancers. Following in vivo IUDR labelling, dual parameter flow cytometry was used to measure tumour DNA index (DI) and labelling index (LI) and to derive DNA synthesis time (Ts) and potential doubling time (Tpot). Heterogeneity was seen for all parameters under investigation. Overall coefficients of variation (CV) and logarithmic transformation of Ts and Tpot (due to their non-gaussian distributions) indicate that LI (CV 25%) was the most variable parameter. Intra-tumoral heterogeneity in Tpot (lnTpot CV = 22%) was less than inter-individual variation (CV = 63%), suggesting that this variation should not be a limitation to the possible usefulness of this technique as an independent prognostic indicator. Correlations of Tpot values were examined between the shortest, the median and the value for a pooled homogenate sample from a single tumour. Using an homogenate, it was possible to accurately predict classification of tumour Tpot values as being below the median ('fast tumours') in 15 of 19 cases (79%). The data suggest that assaying an homogenate may allow a more rapid analysis of a multiply sampled tumour.

DNA heterogeneity in prostatic adenocarcinoma. A DNA flow cytometric mapping study with whole organ sections of prostate

BACKGROUND

The degree of DNA heterogeneity varies between tumors arising at different sites. The presence of a significant degree of variability within a given tumor may result in problems in the interpretation of DNA flow cytometric findings. This study evaluated the degree of DNA heterogeneity in prostatic adenocarcinoma.

METHODS

A total of 122 3-mm punch biopsy specimens were evaluated from single representative whole organ sections from nine cases of prostate cancer (range, 4-18 samples per case; mean, 12 samples; median, 14 samples). Individual punch biopsy specimens were graded and reviewed to confirm the presence of carcinoma and processed for DNA ploidy analysis.

RESULTS

Assessable histograms, defined as having a coefficient of variation of the diploid G0/G1 peak of 7.5% or less, were available for 111 (91%) of the samples. Of the nine cases studied, five (56%) showed heterogeneity in the DNA pattern (diploid plus aneuploid, n = 1; diploid plus tetraploid, n = 2; and diploid plus tetraploid plus aneuploid, n = 2). All four cases having a homogeneous DNA content were DNA diploid in all samples. In those cases with a heterogeneous pattern, the areas having abnormal DNA patterns could not be predicted by histologic pattern or grade.

CONCLUSIONS

From this study, the authors conclude that a significant degree of DNA heterogeneity exists within individual cases of prostatic adenocarcinoma, and this may be an important confounding factor in DNA ploidy studies.

Poor prognosis associated with elevated serum CA 19-9 level in advanced colorectal carcinoma, independent of DNA ploidy or SPF

DNA ploidy, S-phase fraction (SPF) for the tumours, serum tumour markers such as carcinoembryonic antigen (CEA) and serum CA 19-9 and major clinical parameters were analysed as prognostic factors in 105 patients with advanced colorectal carcinoma. All 105 were treated with a three-drug schedule including low dose epirubicin and sequential methotrexate, 5-fluorouracil, followed by leucovorin rescue. In univariate analysis, gender, Karnofsky index, extent of metastases, presence of abdominal metastases, CEA and CA 19-9 correlated with survival. Age, presence of liver or of lung metastases, DNA ploidy or SPF were not significantly associated with survival. In stepwise multivariate analysis an elevated serum CA 19-9 level, a poor Karnofsky index and multiple sites of metastases were independent adverse prognostic factors. Based on the multivariate analysis, patients were grouped in three categories. Group 1 consisted of 32 patients with Karnofsky > or = 80, with a normal serum CA 19-9 level and a single site of metastases. Group 2 consisted of 48 patients with Karnofsky > or = 80 and with an elevated serum CA 19-9 level or multiple sites of metastases. Group 3 consisted of 14 patients with Karnofsky < or = 70. This classification gave a highly significant correlation with survival (chi 2 = 45.52, P < 0.001, log rank test). The median survival in group 1, group 2 and group 3 was 30.1 months, 13.5 months and 3.9 months, respectively. Based on these results we suggest that trials involving advanced colorectal cancer should include the measurement of serum CA 19-9 levels as one of the most important prognostic factors, but also include documentation of other independent prognostic factors.

Quality control study of the Italian group of cytometry on flow cytometry cellular DNA content measurements

A quality control study on DNA flow cytometry, extended to 43 national laboratories, has been carried out by the Italian Group of Cytometry, using defined fixed suspensions of cultured human leukemia K562 cells and human blood lymphocytes. The participating laboratories were allowed to follow their own staining and measurement protocols. Aliquots of cellular suspension had to be measured three times on the same day and two other times on different days. A large heterogeneity of procedures emerged among participants. The average of mean DNA index laboratory values, from 36 laboratories who sent evaluable data, was 1.68, with a range from 1.49 to 1.97. The coefficients of variation ranged from 2.35 to 9.39% and from 2.79 to 8.5% for diploid and aneuploid peaks, respectively. Statistical analysis of the results showed quite good intralaboratory reproducibility, but statistically significant differences were observed among laboratories, for both DNA indices and coefficients of variation. These differences appear to be consistent. For standardization, it is essential that efforts should be made to identify the main sources of variation and to control them.

Regional DNA content heterogeneity in colonic adenocarcinoma: prognostic significance in patients with liver metastases

We retrospectively examined by flow cytometry the DNA ploidy pattern in tissue blocks from 25 primary colon adenocarcinomas and their lymph node and liver metastases. Intratumoral heterogeneity was present in 22% of primary tumors and 21% of metastatic liver deposits. Intertumoral heterogeneity, measured between the primary tumor and its lymph node and liver metastases, was 0% and 20%, respectively. Of 24 patients who underwent successful resection of their liver metastases, 8 neoplasms had uniformly diploid DNA content, while 16 tumors had aneuploid DNA pattern in either the primary tumor, the metastases, or both. Five-year survival was better in the diploid group (38% vs. 7%, P = 0.10 by log rank analysis). Three of eight patients in the diploid group remain free of disease, while all 16 patients with aneuploid cell populations have died of recurrent disease.

The study of endocrine tumors by flow and image cytometry

Both DNA flow and image cytometry are methods that can be used for the quantitative determination of cellular DNA content. Objective, quantitative analysis of cellular morphology can also be obtained using image cytometry. Data thus generated have been shown to be of diagnostic and prognostic use in the study of many solid tumors and would be of particular value in the evaluation of endocrine tumors that show a poor correlation between their histology and biological behavior. The main application of these techniques to endocrine tumors has been in the analysis of thyroid nodules, although a limited number of studies of parathyroid, pituitary, adrenal, and pancreatic neuroendocrine tumors and tumors of the dispersed neuroendocrine system have been reported. Review of these studies shows that in the endocrine organs DNA and morphometric measurements have a very limited role in the diagnosis of individual cases, but are important as prognostic variables. The high incidence of abnormal DNA content in histologically benign lesions of the endocrine glands has important biological implications. Further investigation of this phenomenon may help to elucidate the process of endocrine tumorigenesis.

Flow cytometric analysis of nuclear DNA content in ovarian tumors. Association of ploidy with tumor type, histologic grade, and clinical stage

The authors undertook a prospective, flow cytometric study of nuclear DNA ploidy in 140 fresh ovarian tumors. There were 43 benign tumors, 27 borderline tumors, and 70 malignant tumors. Results of DNA ploidy analysis were compared to age at diagnosis, menopausal status, tumor size, histologic type, grade, and International Federation of Gynecology and Obstetrics (FIGO) stage. Although the majority of benign tumors were diploid, 19% were aneuploid. Among the benign tumors, DNA ploidy was significantly associated with tumor type and tumor size. All borderline tumors were diploid. Of the 70 malignant tumors, 64% were aneuploid. In the malignant tumors, DNA aneuploidy had significant univariate associations with histologic type, grade, and FIGO stage. By multivariate analysis, DNA aneuploidy remained significantly associated with stage and grade, both known predictors of survival in ovarian cancer. These results indicate that DNA ploidy varies with the aggressive potential of an ovarian cancer and may, at the time of initial diagnosis, provide additional information about tumor prognosis.

Epithelioid sarcoma. Flow cytometric study of DNA content and regional DNA heterogeneity

The DNA content and regional DNA heterogeneity in correlation with clinicopathologic parameters and patient survival were investigated in epithelioid sarcoma. Such neoplasms preponderantly manifest diploid DNA content and a remarkably stable intratumoral and intertumoral DNA content. Small tumor size (less than 5.0 cm) and low S-phase fraction (less than 5%) were significant prognostic factors in this study. Ploidy status, mitotic rate, age, and postsurgical treatment were not significantly correlated with survival.

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.