Renal cell carcinoma. A clinicopathologic and DNA flow cytometric analysis of 103 cases

Numerical aberrations of chromosomes 1 and 7 in renal cell carcinomas as detected by interphase cytogenetics

Alcohol-fixed single cell suspensions of 37 renal cell carcinomas (RCCs) were assessed by both flow cytometry (FCM) and the fluorescence in situ hybridization (FISH) technique, using chromosome 1- and chromosome 7-specific centromere DNA probes. DNA diploidy or near-diploidy was observed in 30 of the 37 RCCs and only 12 of these (near-)diploid tumours were disomic for both chromosomes 1 and 7. Numerical aberrations of chromosome 1 and/or chromosome 7 were present in 18 of the 30 (near-)diploid RCCs and five of these cases showed monosomy for chromosome 1 in more than 50 per cent of the tumour cells. A double target FISH, with a centromeric and a telomeric specific probe for 1p36, excluded misinterpretation on the basis of clustering of 1q12, and suggested a complete loss of chromosome 1. All these five (near-)diploid RCCs with monosomy for chromosome 1 were eosinophilic chromophilic cell carcinomas, according to the Thoenes classification of RCC. This observation is of special interest, because it was recently concluded from cytogenetic studies that the diagnosis of chromophilic renal cell carcinoma must be considered as obsolete. Monosomy for chromosome 1 seems to be a non-random numerical aberration of (near-)diploid eosinophilic chromophilic cell carcinomas, and a gain of one or more chromosomes 1 appeared to be a common phenomenon in RCCs, especially in the DNA aneuploid tumours. As these chromosomal abnormalities were not found in the earlier classical cytogenetic studies, we conclude that in situ hybridization techniques are required in addition to chromosome banding techniques to obtain a complete characterization of the chromosome imbalances in RCCs.

DNA flow cytometric analysis in renal neoplasms associated with acquired renal cystic disease

In order to better understand the potential malignancy of renal neoplasms arising in patients with acquired renal cystic disease and to try and establish differences from other renal tumours we analysed DNA ploidy as well as the level of S-phase fraction in 11 neoplasms associated with acquired cystic disease by means of flow cytometry. The results were correlated with known prognostic factors such as nuclear grade, size and stage, as well as the clinical behaviour of the tumours. We found a close relationship between DNA aneuploidy and high S-phase fraction and a poor clinical outcome. We also found some differences in the DNA ploidy profile of these tumours when compared with those reported in other renal neoplasms.

Cell kinetics of renal cell carcinoma studied with in vivo iododeoxyuridine incorporation and flow cytometry

In 29 patients with renal cell carcinoma tumor cell kinetics were studied by in vivo labeling with 100 mg. iododeoxyuridine given 3 to 7 hours before nephrectomy. Two to 6 samples were analyzed from each tumor after fixation in ethanol. Iododeoxyuridine was analyzed by specific antibodies using flow cytometric analysis of labeled cells and parameters, such as labeling index and potential tumor doubling time, could be determined. Samples from 28 tumors were evaluable. Mean labeling index of the tumors was 2.7%, which was significantly different from the 0.35% index in kidney cortex tissue. There was no statistical difference in labeling index among the clinical stages. The mean potential tumor doubling time in the tumor cells was 20.3 days, which was significantly different compared with 137.7 days in kidney cortex tissue. There was a frequent intra-tumoral heterogeneity of potential tumor doubling times. Diploid and aneuploid samples had significantly different potential tumor doubling (mean 37.4 and 12.5 days, respectively). Potential tumor doubling had a significant impact on the survival time (p = 0.004), which also was noted in the patients with aneuploid tumors (p = 0.003). Our study shows that in vivo incorporation of iododeoxyuridine successfully can be analyzed in renal cell carcinoma. Potential tumor doubling time gives valuable prognostic information on the clinical behavior of the patients.

Tumor-cell proliferation and prognosis in renal-cell carcinoma

In the present study the prognostic value of tumor S-phase fraction was evaluated in 69 patients with renal-cell carcinoma. The proportion of S-phase cells was calculated from DNA histograms by flow cytometry in multiple samples from each tumor. The mean tumor S-phase percentage varied between 1.0 and 17.0%, mean 7.5%, with a significant difference between diploid and non-diploid tumors. Stage-I tumors showed significantly lower S-phase values than tumors of stages II/III and IV. Histopathological grade correlated with fraction of cells in S-phase. Nineteen tumors were homogeneously diploid, I was tetraploid and 49 were aneuploid. Heterogeneity concerning S-phase values was found in 46 of the 69 tumors and concerning DNA ploidy in 34 tumors. Survival time was longer for patients with diploid tumors than for those with aneuploid tumors. Patients with S-phase values < 7.5% had a longer survival time than patients having tumors with S-phase values > 7.5%. Within the group of aneuploid tumors, patients with S-phase values < 7.5% had a significantly better prognosis. In multivariate analysis, only tumor stage and S-phase gave significant independent prognostic information. The S-phase fraction seems to be an additional prognostic parameter for patients with renal-cell carcinoma.

Localized renal cell carcinoma treated by radical nephrectomy. Influence of pathologic data and the importance of DNA ploidy pattern on disease outcome

BACKGROUND

The course of patients with renal cell carcinoma may be considerably different. Approximately 50% with presumed localized disease have metastases after nephrectomy. Pathologic stage at diagnosis, histologic grade, and histologic type have been considered the most important predictors of prognosis. Nevertheless, subsets of patients within a specified stage and grade may have considerable differences in disease progression and survival.

METHODS

Flow cytometric nuclear DNA analysis was used to study pathologic Stage I or II renal cell carcinoma in 54 patients who underwent radical nephrectomy between 1974 and 1983.

RESULTS

Sixty-three percent of the tumors were diploid, and 37% aneuploid. A DNA diploid pattern was more common among Stage I tumors than Stage II tumors (69% versus 33%; P < 0.04). Progression occurred in 31% of the diploid tumors, whereas among the aneuploid group the progression rate reached 59% (P < 0.06). Considered as a single indicator, DNA ploidy pattern was strongly associated with patient survival. Ten years after surgery 79% of the patients who had diploid tumors and 50% of those with aneuploid tumors were alive (P < 0.02).

CONCLUSIONS

Nuclear DNA ploidy may serve as an important prognostic variable for patients with early stage renal cell carcinoma.

Papillary renal cell carcinoma: clinical implication of DNA content analysis

Papillary renal cell carcinoma is considered a less-aggressive histomorphologic variant of renal cell carcinoma. We investigated the clinicopathologic features and the DNA ploidy pattern in 22 papillary renal cell carcinoma cases and correlated the findings to the patients' length of survival. In this study the demographic data were similar to those of previously published series. Histologically, two neoplasms were Fuhrman's nuclear grade 1, eight were nuclear grade 2, 11 were nuclear grade 3, and one was nuclear grade 4. Six tumors were stage I, three were stage II, five were stage III, and eight were stage IV. With a mean follow-up period of 42 months, eight patients died of disease and 14 were alive and well. DNA aneuploidy was found in 50% of the neoplasms and was frequently associated with high tumor nuclear grade, high tumor stage, and poor prognosis. Conversely, DNA diploidy was preponderantly noted in neoplasms with low tumor nuclear grade and stage, and none of the patients died of their disease. A statistically significant difference between DNA ploidy/tumor stage and patient outcome was obtained. No significant correlation between DNA ploidy and nuclear grade was observed. Our results suggest that DNA content measurements may assist in evaluating the clinical outcome of this neoplasm. Moreover, they indicate that papillary renal cell carcinomas manifest clinicopathologic, DNA content, and biologic characteristics akin to those of nonpapillary variants.

Intratumoural heterogeneity of nuclear DNA-content and proliferation in clear cell type carcinomas of the kidney

Clear celled renal carcinomas (n = 37) were investigated by flow cytometry for intratumoural heterogeneity in DNA-ploidy and proliferation (S-phase rate). Using gross sections of the tumours, 178 regions of interest were selected and excised from the paraffin blocks. Of the tumours examined 30% (n = 11) were DNA-diploid and 70% (n = 26) were DNA-aneuploid. In six tumours (16%) homogenous DNA-aneuploidy was detected, and in 20 others (54%) there was intratumoural heterogeneity of DNA-content with a blend of either DNA-diploid and DNA-aneuploid regions (n = 16; 43%) or different aneuploid stemlines (n = 4; 11%). DNA-aneuploidy was present both in areas of the tumours composed of clear cells and in regions containing cells with cytoplasmatic eosinophilia. However, DNA-aneuploidy was correlated in a statistically highly significant manner with the degree of cytoplasmatic eosinophilia and the nuclear grading of tumour cells. The results were confirmed by comparative analysis of fresh-frozen and paraffin-embedded material. The DNA-aneuploid portions of the tumours, and the regions with increased cytoplasmatic eosinophilia, proved to have significantly higher S-phase rates than DNA-diploid and clear tumour cells. These results agreed well with the immunohistochemically determined percentage of Ki-67 (proliferation associated)-antigen positive cells. Our findings indicate that tumour cells with increased eosinophilia in renal cell carcinomas are distinct from real clear cells by virtue of their higher rates of aneuploidy and proliferative activity. These cells might therefore be regarded as a subclass with a more aggressive biological behaviour.

Does DNA flow cytometry give useful prognostic information in renal parenchymal adenocarcinoma?

DNA ploidy and S-phase fraction (SPF) were measured by flow cytometry on 381 paraffin blocks from 93 unselected primary renal parenchymal adenocarcinomas (RPA). The results were compared with tumour grade and T category and patient survival, with a mean follow-up of 87 months. Only 21% of the tumours were uniformly diploid and ploidy was heterogeneous in 49% of cases. DNA ploidy and SPF were significantly associated with grade, but not T category of disease. Both flow cytometric parameters were significantly related to survival in a univariate analysis. However, when tumour grade was taken into account, both DNA ploidy and SPF lost their prognostic significance. Thus, neither of these parameters gave prognostic information additional to that provided by tumour grade in unselected cases of primary RPA.

Cell proliferation in human tumours growing in nude mice: renal cell carcinomas, larynx and hypopharynx carcinomas

Cell proliferation of 51 human renal cell carcinomas and 9 larynx and hypopharynx carcinomas has been studied in vitro and using xenotransplants. The proliferative activity ([3H]thymidine labelling index) increases during the first passages in nude mice and then remains almost constant throughout subsequent passages. A comparison of cell kinetic parameters of 8 human renal cell carcinomas, 1 hypopharynx and 2 larynx carcinomas, with data of xenografts and of human tumours in situ published up to now, shows that the cell kinetic parameters of human tumour xenografts presently studied range between those of human tumours in situ and those of autochthonous or transplantable mouse tumours. S-phase durations and potential doubling times are considerably shorter in xenotransplants than in human tumours in situ, whereas the cycle time is about the same. This means that the growth fraction increases considerably after xenotransplantation. This change of human tumour cell proliferation after transplantation into nude mice should be kept in mind if one wishes to draw conclusions from the nude mouse model on conditions in human beings, particularly with respect to therapeutic regimens, which are frequently tested in the nude mouse model.

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.

DNA ploidy in cell nuclei from paraffin-embedded material--comparison of results from two laboratories

In 49 pairs of contiguous sections from paraffin-embedded prostatic cancer tissue, the DNA indices (DIs) were determined by flow cytometry (FCM) at 2 different laboratories. In 3 of 45 pairs of evaluable nuclear suspensions, DIs of 1.1 (DNA aneuploid) were found at Laboratory 1, whereas all 3 tumours were classified as DNA diploid at Laboratory 2. In the remaining 42 specimens, the correlation between the DIs was excellent, though the application of strictly defined DNA ploidy ranges led to different DNA ploidy allocation in 3 cases. It is concluded that in 85-90% of the cases, reliable DIs can be obtained by FCM done in paraffin-embedded material at different laboratories. Slight technical variations and interpretation differences may lead to different ploidy allocation in 10-15% of the cases.

Flow cytometric deoxyribonucleic acid analysis in stage I renal cell carcinoma

Tumor deoxyribonucleic acid (DNA) content was analyzed by flow cytometry in 60 consecutive patients with stage I renal cell carcinoma. Of 59 evaluable tumors 27 (46%) were homogeneously diploid, 1 (2%) was tetraploid and 31 (52%) were aneuploid. Of the 32 nondiploid tumors 25 were heterogeneous concerning ploidy. One of the 27 patients with diploid tumors had metastases compared to 5 of the 32 patients with nondiploid tumors (not significant). There was a significant difference in survival between patients with diploid and nondiploid tumors (p = 0.043). Neither nuclear grade, tumor cell type nor tumor size correlated with survival. Analysis of DNA content seems to predict survival significantly for patients with stage I renal cell carcinoma.

Excretion of pseudouridine as an independent prognostic factor in renal cell carcinoma

Pseudouridine is the most prevalent modified nucleoside excreted in urine, mainly as a degradation product of t-RNA. The level of pseudouridine excretion was analyzed in 71 patients with renal cell carcinoma prior to treatment. An increased excretion was demonstrated in 27 of 48 patients (56%) in stage II-IV, compared to 2 of 23 patients (9%) in stage I. Survival time was significantly reduced in patients with increased excretion. The level of pseudouridine correlated to tumor grade and tumor size. Using Cox's proportional hazard model, only clinical stage and level of pseudouridine excretion were independent predictors of prognosis.

Nuclear grading of renal cell carcinomas--is morphometry necessary?

Comparative investigations of subjective with objective nuclear grading methods of renal cell carcinomas are almost completely lacking. Therefore, we graded 94 cases of this carcinomas by a simple, subjective microscopical estimation as well as by a morphogenetic measurement of nuclear area. Both procedures proved prognostically useful, but the best results were achieved by morphometry. By this method three prognostic groups of renal cell carcinoma were found, provided that the borderlines were drawn at 28 microns 2 and 60 microns 2, respectively. Particularly favourable and unfavourable cases could be separated from average ones, if the means and standard deviations of both the nuclear areas and the diameters were evaluated. Overall, morphometric nuclear analyses are highly desirable, if, for example, morphological data are to be used in the context of prognostic or therapeutic studies on renal cell carcinoma. However, there is a broad distribution of the values for individual cases so that, tumour-biologically, no exact demarcation of prognostically different groups can be expected.

Primary sarcomas of the kidney. A clinicopathologic and DNA flow cytometric study of 17 cases

Primary sarcomas of the kidney in adults are rare. In the handful of published reports of all soft tissue sarcomas, DNA ploidy has correlated with histologic grade and outcome. This report presents the clinicopathologic and flow cytometric features of 17 cases of primary renal sarcoma (seven men and ten women, ages 28-69 years). Presenting symptoms included abdominal and back pain and hematuria. Stages at diagnosis were I, in three patients; II, five patients; III, two patients; and IV, two patients. Eight tumors were leiomyosarcoma, two malignant fibrous histiocytoma, one hemangiopericytoma, one fibrosarcoma, and five unclassified. Tumors measured 5.5 to 23 cm, seven contained marked nuclear pleomorphism, seven were extensively necrotic, and mitotic rate was 1 to 33 per 10 high-power fields. Seven tumors showed aneuploidy and five were diploid. Thirteen patients were dead of disease after a mean of 23 months and two were alive with known metastases at 29 and 33 months, respectively. Ploidy pattern and outcome or time to death were not correlated, but aneuploidy correlated with histologic grade, marked nuclear pleomorphism (P less than 0.05), extensive necrosis (p less than 0.01), and high mitotic rate (0.05 less than P less than 0.10). The authors conclude that although DNA ploidy does correlate with histologic grade, for primary renal sarcomas, whose prognosis in this series was extremely poor, it does not correlate with outcome.