Tumour characteristics and survival in patients with invasive interval breast cancer classified according to mammographic findings at the latest screening: a comparison of true interval and missed interval cancers

The aim of this study was to investigate whether different mammographic categories of interval cancer classified according to findings at the latest screening are associated with different distributions of prognostic factors or with different survival rates. The series consisted of all patients with invasive interval cancer detected from May 1978 to August 1995 (n = 544). The tumours were evaluated with regard to age, radiological category, interval between the latest screen and diagnosis and tumour characteristics at the time of diagnosis. We investigated possible relationships between the survival rate of patients with interval cancer and the interval between the latest screen and diagnosis, tumour characteristics and radiological category of the interval tumours. The study focused on comparison of patients with true interval and missed interval cancer. Women with mammographically occult tumours were younger than those in the other radiological categories. Comparisons of true interval cancers with overlooked or misinterpreted tumours showed equal distributions of age, tumour size, TNM stage and lymph node status. The overlooked or misinterpreted tumours showed significantly higher proportions of grade-I tumours (22 vs 11 %), tumours with low S-phase fraction (SPF; 44 vs 24 %) and oestrogen receptor (ER) positive tumours (72 vs 57 %). However, analyses of survival rates disclosed no clear differences between the two radiological categories. Radiological category and interval between the latest screen and diagnosis were not genuine predictors of the prognosis in patients with invasive interval breast cancer. No certain prognostic difference existed between true interval cancers and overlooked or misinterpreted interval breast cancers, despite higher proportions of grade-I tumours, ER positive tumours and tumours with low SPF in the latter group.

Different calculation methods for flow cytometric S-phase fraction: prognostic implications in breast cancer? The Swedish Society of Cancer Study Group

S-phase fraction (SPF), estimated in the flow cytometric DNA histogram, is a prognostic factor in breast cancer. There are, however, some inherent difficulties in the estimation of SPF, such as the influence of debris, aggregates, and normal cells. Most of the available SPF calculation principles try to consider these difficulties, but so far no consensus has been reached with regard to which principle is to be recommended. The aim of the present study was to investigate the prognostic impact of SPF when estimated with different calculation methods in frozen breast cancer samples from 350 patients. Two nonparametric (Rman, Rmin/both rectangle) and three parametric (ACAS/DNA-base, ModFit, and MultiCycle) calculation methods, with and without correction for debris and aggregates, were used. The mean values for SPF varied from 4.3% (ACAS/DNA-base with correction for debris and aggregates) to 9.4% (MultiCycle without any correction for background). The pairwise correlation between methods varied considerably (R = 0.72-0.98). After categorization of SPF values into low SPF (lower two tertiles) and high SPF (upper tertile), all methods yielded statistically significant Pvalues for recurrence-free survival (median follow-up time 67 months), both univariately (0.0004-< 0.0001) and multivariately (0.048-0.0004), after adjusting for nodal status, tumor size, and estrogen receptor status. SPF with background correction did not yield lower P values than SPF without. Regardless of which method was used, SPF showed similar correlations with lymph node involvement, tumor size, and estrogen receptor content. In conclusion, as the mean value of SPF for different calculation methods varies, each laboratory must be restricted to use only one method. Background correction does not seem to improve the prognostic impact of SPF in DNA histograms. Based on the experiences obtained in the present study, S-phase calculation methods without background correction may therefore be the most suitable for routine evaluation of DNA histograms of fresh frozen breast cancer material (ModFit, MultiCycle, and Rman [the latter only for experienced operators]). The nonparametric Rmin, with an automatic setting of the region used for SPF calculation, may be an alternative, but suffers from the disadvantage of not being commercially available yet.

S-phase fraction assessed by a variant of the rectangular model adapted to the flow-cytometric DNA histogram profile

Measurement of S-phase fraction by DNA flow cytometry is widely used in the analysis of human tumors. The calculation of fraction of S-phase cells is performed either by means of curve-fitting techniques or by more simple planimetric methods. Estimates by the latter often suffer from subjectivity or poor adaptation to complex DNA histograms. We describe a variant which is based on the rectangular model. The height of the rectangle is automatically determined from the lowest density value in the S-phase interval. The variant was tested on 141 DNA histograms, and the results were compared with those obtained with other variants based on the rectangular model. The new variant is thought to circumvent some of the problems concerning subjectivity and disturbances caused by aggregate peaks.

Overexpression of MDM2 in acute childhood lymphoblastic leukemia

Mutation of the TP53 gene is one of the most common molecular alterations in a variety of tumors, but it occurs infrequently in childhood and adult hematological malignancies. Protein accumulation often results from mutations that lead to inactivation of the p53 protein. Other causes of functional inactivation of the p53 protein include stabilization of p53 via proteins such as MDM2, an oncoprotein capable of forming specific complexes with p53. In the present study, protein expressions of MDM2 and p53 were investigated by immunohistochemistry from bone marrow samples in 23 patients with acute lymphoblastic leukemia aged 1-13 years at diagnosis. p53 protein overexpression was detected in only one case, while overexpression of MDM2 was detected in samples from five patients. All five patients overexpressing MDM2 belonged to a group with unfavorable prognostic signs at diagnosis and three of them relapsed or died within 6 months after diagnosis.

Intra- and inter-laboratory reproducibility of estrogen and progesterone receptor enzyme immunoassay in breast cancer cytosol samples--a Swedish multicenter study. Swedish Society of Cancer Study Group

Estrogen and progesterone receptor analysis results were compared within and between six laboratories in Sweden using frozen breast cancer cytosol samples, and the same technique (enzyme immunoassay, Abbott Laboratories). The concordance in receptor status (positive vs. negative) was excellent (98.4% (571/580)). The discordant results were attributable to values near cut-off (n = 4) or outliers (n = 5), the latter probably being due to analytical errors. One laboratory reported significantly higher ER concentrations than the others; thus caution should be observed when comparing absolute values from different centers. For PgR there were similar differences between the laboratories. However, the intra- and inter-laboratory differences were small compared with the overall variability in ER and PgR content between different samples in a large database. The range of the median intra-laboratory coefficient of variation was 11-23% for ER and 12-19% for PgR, indicating that there is room for improvement in the quality of assay performance.

Interval cancers and cancers in non-attenders in the Ostergötland Mammographic Screening Programme. Duration between screening and diagnosis, S-phase fraction and distant recurrence

The study was based on a population mammographic screening programme for women aged 40-74 years. Metastatic potential was analysed in 843 invasive breast cancers with regard to mode of detection and a number of prognostic factors. There was a higher metastatic capacity in clinically detected cases, but multivariate analyses showed that neither the mode of detection (hazard rate ratio of distant recurrence RR = 1.39, 95% CI 0.78-2.46 interval cancers and RR = 1.6, 95% CI 0.76-3.36 non-attenders) nor the duration between screening and diagnosis for true interval cancers (RR = 0.47, 95% CI 0.16-1.35 in tumours detected later than one year after screening) were independent prognostic factors. A correlation was found between metastatic potential and the SPF (RR = 2.94, 95% CI 1.57-5.50 in tumours with a high SPF), the oestrogen receptor status and the tumour stage. In conclusion, interval cancers intrinsically are not different from other breast cancers with equivalent characteristics; the duration between screening and diagnosis in interval cancers was not clearly correlated to the prognosis, but the S-phase fraction was a powerful predictor of prognosis.

Proliferating cell nuclear antigen (PCNA) in relation to ras, c-erbB-2,p53, clinico-pathological variables and prognosis in colorectal adenocarcinoma

Proliferating cell nuclear antigen (PCNA) expression was studied by immunohistochemistry on paraffin-embedded sections of 293 primary colorectal adenocarcinomas and 56 corresponding lymph node metastases. PCNA-positive expression was detected in <25% of tumour cells in 172 (59%) cases and in > 25% in 121 (41%) cases. PCNA accumulation was related to over-expression of c-erbB-2 and p53 and tended to be increased in cases with ras over-expression. PCNA expression was identical in primary and corresponding metastases. No significant relationship was observed between PCNA expression and prognosis and other clinico-pathological variables, including grade of differentiation, growth pattern, Dukes' stage, site, age or sex. We conclude that PCNA expression may be related to alterations of oncoproteins but that PCNA itself could not provide additional information for the development of metastasis and prognosis in colorectal adenocarcinoma.

Proliferating cell nuclear antigen (PCNA) in relation to ras, c-erbB-2,p53, clinico-pathological variables and prognosis in colorectal adenocarcinoma

Proliferating cell nuclear antigen (PCNA) expression was studied by immunohistochemistry on paraffin-embedded sections of 293 primary colorectal adenocarcinomas and 56 corresponding lymph node metastases. PCNA-positive expression was detected in <25% of tumour cells in 172 (59%) cases and in > 25% in 121 (41%) cases. PCNA accumulation was related to over-expression of c-erbB-2 and p53 and tended to be increased in cases with ras over-expression. PCNA expression was identical in primary and corresponding metastases. No significant relationship was observed between PCNA expression and prognosis and other clinico-pathological variables, including grade of differentiation, growth pattern, Dukes' stage, site, age or sex. We conclude that PCNA expression may be related to alterations of oncoproteins but that PCNA itself could not provide additional information for the development of metastasis and prognosis in colorectal adenocarcinoma.

Interrelations of clinicopathologic variables and their prognostic value in colorectal adenocarcinoma

We analyzed the interrelations of sex, age, tumor site, Dukes' stage, growth pattern and differentiation, and their prognostic value in 293 patients with primary colorectal adenocarcinoma. Simultaneously, growth pattern, differentiation, DNA and S-phase fraction (SPF) in paired primary tumors and lymph node metastases from 97 colorectal cancer patients were compared. The results revealed that poorly differentiated and mucinous tumors, as against well/moderately differentiated tumors, were frequently located in the proximal colon, and their frequencies were increased as Dukes' stage advanced (p=0.03). Tumor differentiation was usually identical in primaries and corresponding metastases (p=0.002), but this was not true of tumor growth pattern, DNA ploidy or SPF. In multivariate survival analyses, Dukes' stage provided strongly prognostic information (p<0.001) and mucinous tumors tended to predict worse survival (p=0.08).

c-erbB-2 expression and benefit from adjuvant chemotherapy and radiotherapy of breast cancer

Frozen tissue from primary tumours of 152 premenopausal breast cancer patients, who participated in a trial comparing radiotherapy with adjuvant chemotherapy (cyclophosphamide, methotrexate, 5-fluorouracil, CMF), was analysed for c-erbB-2 protein expression, measured by flow cytometry. The relative risk of distant recurrence or death in the chemotherapy group as compared with the radiotherapy group was 3.0 (95% confidence interval (CI) 1.1-7.8) for patients whose tumours showed high c-erbB-2 levels and 0.87 (95% CI 0.43-1.7) for those with tumours with low levels of c-erbB-2 protein. Patients with highly proliferative tumours that did not overexpress c-erbB-2 benefited most, in terms of survival, from CMF. In addition, we found an increased risk of locoregional recurrence for tumours overexpressing c-erbB-2 when radiotherapy was replaced by chemotherapy.

Loss of cytokeratins in breast cancer cells using multiparameter DNA flow cytometry is related to both cellular factors and preparation procedure

In breast carcinomas, S-phase fraction calculated after flow cytometric selection of epithelial cells improves the prediction of distant recurrence. However, the presence of DNA aneuploid cells registered as non-epithelial cells and the intertumoural variation of cytokeratin positivity may cause selective loss of tumour cells in flow cytometric analysis. In the present study, the expression of cytokeratins 8 and 18 was examined by both immunohistochemistry and flow cytometry. The proportion of cytokeratin-positive cells was decreased by 25% when estimated by flow cytometry compared with immunohistochemistry; however, the correlation between these two methods was significant (P < 0.01). Fewer cells were cytokeratin-positive in DNA hypodiploid tumours compared with DNA diploid and DNA aneuploid tumours (P = 0.006). Also, rapidly proliferating tumours tended to have a smaller proportion of cytokeratin-positive tumour cells. Our results indicate that loss of cytokeratins in breast cancer cells is related to both cellular factors and the preparation procedure.

p53 as a prognostic factor in stage I breast cancer. South-East Sweden Breast Cancer Group

Accumulation of the tumour-suppressor protein p53 in breast cancer is associated with several prognostic factors that indicate an aggressive, rapidly proliferating tumour with an unstable genome. To assess p53 accumulation in stage I breast cancer and to evaluate the prognostic value of both nuclear and cytoplasmic p53, 205 patients with node-negative breast cancer and tumour size less than or equal to 20 mm were examined. Immunohistochemistry was performed on frozen sections with the monoclonal antibodies PAb 1801 and DO1. Cellular p53 accumulation, within either the nucleus or the cytoplasm or in both, showed the same association with different pathobiological variables as nuclear accumulation alone. Eleven per cent of the tumours showed strong nuclear accumulation and were significantly correlated to age under 50 years, negative oestrogen receptor status, DNA aneuploidy, high S-phase fraction, high pathological grade and poor prognosis. The distant recurrence rate ratio was 6.2 (P = 0.002). It is thus concluded that p53 accumulation is of prognostic value in early stage breast cancer.

Prognostic significance of p53 overexpression in primary breast cancer; a novel luminometric immunoassay applicable on steroid receptor cytosols

A novel quantitative luminometric immunoassay (LIA) has been developed for the measurement of wild-type and mutant p53 protein in extracts from breast tumour tissue. The LIA was found to yield reliable estimates of p53 expression in cytosol samples routinely prepared for steroid receptor analysis as compared with results obtained with immunohistochemical analysis. The LIA was evaluated on 205 primary breast tumour cytosols prepared for steroid receptor analysis and stored frozen at -80 degrees C for 6-8 years, p53 protein being detected in 65% of the samples (range 0.01-23 ng mg-1 protein). Using an arbitrary cut-off value of 0.15 ng mg-1 protein, 30% of the tumours were classified as manifesting p53 overexpression. Significant and independent correlations were found to exist between p53 overexpression and shorter disease-free (P < 0.001) and overall survival (P = 0.039) at a median duration of follow-up of 50 months. p53 overexpression was related to low oestrogen receptor content and high proliferation rate (S-phase fraction). No relationship was found to tumour size or the presence of lymph node metastasis. Three tumours possessed an extremely high p53 content (> 10 ng mg-1 protein), all of which were of medullary or high-grade ductal type, oestrogen and progesterone receptor negative, DNA non-diploid, had S-phase fractions of > 22% and recurred within 1-2 years. In summary, a new sensitive and quantitative LIA suitable for routine analysis of p53 protein in steroid receptor cytosol preparations from breast tumours has been developed to confirm the prognostic importance of p53 protein accumulation in human breast cancer.

c-erbB-2 oncoprotein in relation to DNA ploidy and prognosis in colorectal adenocarcinoma

Overexpression of the c-erbB-2 oncogene has been demonstrated in a variety of tumours, including colorectal tumours. In breast carcinoma, c-erbB-2 overexpression is associated with DNA ploidy, some other prognostic indicators, and unfavourable survival prospects. However, there is little such information available regarding colorectal tumours. In this study, c-erbB-2 was analysed retrospectively by immunohistochemistry in 293 primary colorectal adenocarcinomas to assess its relation to DNA ploidy, S-phase fraction, other prognostic factors, and patient survival. Using the monoclonal antibody NCL-CB11, we found that 23% of the tumours were strongly c-erbB-2 positive, while 36% showed weak expression. The highest frequency of c-erbB-2 expression was 81% in DNA tetraploid tumours, compared to 63% in aneuploid and, 53% in diploid tumours (test for heterogeneity, p = 0.031). Overexpression of c-erbB-2 indicated a favourable prognosis in patients with DNA aneuploid tumours (p = 0.0088), but not in those with diploid or tetraploid tumours. The prognostic value of c-erbB-2 in DNA aneuploid tumours remained even after adjustment for Dukes' stage (p = 0.027). The results suggest that a combination of c-erbB-2 expression and DNA ploidy may improve the identification of patients' risk of cancer death.

p53 expression and the result of adjuvant therapy of breast cancer

Functional p53 protein is essential for the cellular response to drug-induced DNA damage. We investigated p53 accumulation in tumour specimens from premenopausal breast cancer patients who were randomised to adjuvant chemotherapy (CMF) or postoperative radiotherapy. Of the tumours from 139 patients, 20 showed abnormal accumulation as judged with immunohistochemistry (> 10% positive tumour cells). The risk of distant recurrence was similar in the two treatment groups for patients whose primary tumours lacked p53 accumulation, whereas there was a significant benefit from CMF for patients showing abnormal accumulation (relative risk 0.18, 95% CI, 0.04-0.93). This result suggests that p53-dependent apoptosis is not a general mechanism by which breast cancer cells respond during CMF chemotherapy.

S-phase fraction and survival benefit from adjuvant chemotherapy or radiotherapy of breast cancer

Cancer chemotherapy interacts with cell proliferation, but data on the relationship between cancer cell replication and the effect of adjuvant chemotherapy are scarce. We have investigated the S-phase fractions of the primary tumour from premenopausal breast cancer patients who participated in a randomised trial comparing 12 cycles of polychemotherapy (CMF) with post-operative radiotherapy. DNA flow cytometry was performed on frozen tissues from 208 primary breast carcinomas, of which the S-phase fraction was estimated in 176 cases. There was a significantly higher benefit from CMF among patients with a high S-phase fraction (P = 0.0033). The relative risk of distant recurrence or death in the chemotherapy group as compared with the radiotherapy group was 0.19 for patients whose tumours had an S-phase fraction of 10% or over (95% CI 0.07-0.51) and 1.55 (0.88-2.73) for patients whose tumours showed lower S-phase levels. The interaction was still significant in multivariate analysis (P = 0.0057), including lymph node metastases, tumour size and oestrogen receptor content. We conclude that the benefit from adjuvant chemotherapy compared with radiotherapy is largely confined to patients with highly proliferative tumours.

S-phase fraction after gating on epithelial cells predicts recurrence in node-negative breast cancer

We have compared the prediction of distant recurrence for S-phase fraction (SPF) and DNA-ploidy, as estimated by flow cytometry, on an epithelial cell population and an unselected cell population from 268 node-negative breast-cancer patients diagnosed between 1985 and 1988. The tumor tissue was mechanically disintegrated and divided for flow cytometric analysis using both gated cells containing cytokeratin 8 and 18 and ungated cells treated with a detergent-trypsin solution. The relationship to distant recurrence was investigated for flow cytometric data, tumor size and estrogen and progesterone receptor content in univariate and multivariate Cox's regression analysis. The regression analyses were performed on 209 cases with S-phase fractions estimated by both methods. In 11 cases, DNA-ploidy classification differed, reflecting increased sensitivity to minor aneuploid peaks but a decreased ability to separate peaks in the near-diploid region for the gated populations. When SPF were used in univariate analysis as a continuous parameter or the upper tertile was used as cut-off value, SPF from the cytokeratin-gated cell population were most closely associated with recurrence and contributed additional prognostic information to SPF from the unselected cell population in the multivariate analysis. Out of the following variables:tumor size, ER and PR status, SPF and DNA ploidy, only SPF from immunoselected cells contributed prognostic information in multivariate analysis. These results indicate that SPF from immunoselected cell populations improves the prediction of recurrence in node-negative breast cancer.

Simultaneous analysis of c-erbB-2 expression and DNA content in breast cancer using flow cytometry

The c-erbB-2 oncogene is frequently amplified and overexpressed in human breast cancer. We have studied the c-erbB-2 protein in conjunction with DNA content in frozen samples from breast cancers using flow cytometry. The cell suspensions were obtained by mechanical disaggregation followed by a short fixation in 1% paraformaldehyde. The level of c-erbB-2 expression was calculated as a fluorescence index, taking into account the relative amount of total cellular fluorescence compared to nonspecific fluorescence. The flow cytometric value correlated with immunohistochemical results obtained with the same monoclonal antibody (c-neu, clone 9G6). Overexpression of c-erbB-2 was significantly more frequent in DNA aneuploid tumors than in DNA diploid ones and correlated with increasing S-phase fraction and estrogen receptor negativity. In 10 DNA multiploid tumors, the different aneuploid stemlines uniformly expressed c-erbB-2, supporting the hypothesis that overexpression is an early event in breast cancer. Of the 172 tumors, the 37 (22%) judged as positive with immunohistochemistry showed a somewhat higher rate of distant recurrence than others (P = 0.14). The fluorescence index was significantly associated with prognosis (P = 0.0012), as it was also among the immunohistochemically positive cases. If the degree of overexpression is important, then flow cytometry could be a feasible technique for classification.

Flow cytometric analysis of S-phase fraction in breast carcinomas using gating on cells containing cytokeratin. South East Sweden Breast Cancer Group

We investigated distant recurrence and S-phase fraction (SPF), estimated by flow cytometry with and without selection of the epithelial cell population, in 201 stage II breast carcinomas. The tumour tissue was disintegrated mechanically by scissors and one part of the cell suspension was treated with a detergent-trypsin method for single-parameter analysis, and the other part, for immunological selection of epithelial cells, was incubated with a monoclonal antibody (CAM 5.2) recognising cytokeratins 8 and 18 and a secondary fluorescein isothiocyanate-labelled antibody. DNA was stained with propidium iodide. In order to compare the methods, statistical analysis was performed on the 152 tumours with S-phase fraction estimated by both methods. Sixty-five tumours were diploid, 81 were aneuploid and six tumours had different ploidy determined by the two methods. Using univariate regression analysis, SPF of the epithelial cell population predicted recurrence more effectively than SPF from single-parameter analysis. In multivariate regression analysis, SPF of the cytokeratin-containing population added significant prognostic information to the SPF of the non-selected cells. We concluded that the use of flow cytometric selection of epithelial breast carcinoma cells enhances the predictability value of SPF.

S-phase determination of immunoselected cytokeratin-containing breast cancer cells improves the prediction of recurrence

Estimation of S-phase fraction in breast carcinomas with single parameter flow cytometry may include errors due to dilution of cancer cells by host cells. Use of tissue specific markers may to some extent correct for the effect of dilution. S-phase fraction was estimated by flow cytometry with and without immunoselection in 80 DNA-euploid breast carcinomas in stage I-II. The tumor tissue was mechanically disintegrated and fixed in ethanol. A primary antibody, specific for cytokeratins 8 and 18, was added before incubation with the secondary FITC-conjugated antibody. S-phase fraction was calculated for both the gated (cytokeratin-positive) and the ungated cell population. An increasing proportion of tetraploid cells compared to diploid cells was found when the immunoselection method was used. The gated population tended to have a higher S-phase fraction than the ungated population. In univariate analysis S-phase fraction estimated from both ungated and gated cell populations yielded significant information for predicting recurrence when stratified for tumor size and nodal status. In bivariate analysis S-phase fraction of the gated population contributed prognostic information in addition to S-phase fraction of the ungated population when both variables were included in the analysis. Our conclusion is that S-phase fraction calculated from cytokeratin-positive cells provides prognostic information in addition to ungated S-phase values in DNA euploid breast carcinomas.

Prediction of axillary lymph node metastases in a screened breast cancer population. South-East Sweden Breast Cancer Group

To define a subgroup of patients, in whom axillary dissection could be omitted, we analysed the frequency of pathologically confirmed lymph node metastases depending on tumour size, hormonal receptors, DNA ploidy, S-phase fraction (SPF), and clinical nodal status among 1,145 patients with stage I-II breast cancer from an area with ongoing screening. Clinical nodal status and tumour size were strongly correlated to pathological nodal status. Also SPF > 10% was strongly correlated to node positivity in univariate analysis. In multivariate analysis there was still a significant correlation among cases with tumour size < or = 20 mm. In conclusion, patients with clinically negative nodal status, and tumour size < or = 20 mm and < or = 10 mm had pathologically positive nodes in 25% and 15% of cases respectively. The addition of SPF did not lower these figures significantly since small tumours with high SPF are few.

Inter-institutional reproducibility of flow cytometric DNA-analysis in breast carcinomas

In order to study interinstitutional reproducibility of flow cytometric DNA-analysis (DNA-FCM), frozen pieces from 30 consecutive breast carcinomas were analysed by 5 laboratories. Different instruments, preparation and DNA staining methods were used. A concordance in DNA-ploidy status was obtained in 26 of the 30 tumours. The discrepancy can mainly be explained by intratumoural DNA-heterogeneity since a complete agreement in ploidy status was obtained when four of the laboratories analysed the same cell suspension, where solid bits showed differing results. The sampling method seems therefore to be a crucial step for the results and needs further studies. As far as the estimation of S-phase fraction was concerned, one laboratory obtained significantly higher values compared to the other four. The correlation between the other four laboratories varied between r = 0.66-0.92.

Cellular accumulation of p53 protein: an independent prognostic factor in stage II breast cancer

The p53 gene product is a tumour suppressor protein, and alterations of the protein are common in human cancer. Previous studies have focused on nuclear accumulation of p53. To investigate if cytoplasmic accumulation of p53 strengthens the relationships to different pathobiological variables and distant recurrence-free survival in breast cancer, tumours from 164 stage II patients were examined with the monoclonal antibody PAb1801. Nine per cent of the tumours were nuclear positive and 21% were cytoplasmic positive. Cellular p53 accumulation, related to the nucleus or the cytoplasm or both, showed stronger associations with pathobiological variables than nuclear accumulation alone. Accumulation of p53 was significantly correlated to tumour size over 20 mm, negative oestrogen receptor (ER) status, DNA aneuploidy, high S-phase fraction and positive erbB-2 status. Cytoplasmic p53 was significantly correlated to distance recurrence-free survival in patients negative for nuclear p53 (P < 0.0001). Cellular p53 accumulation was an independent prognostic factor, in addition to lymph node status and ER content. We conclude that consideration of cytoplasmic staining enhances the clinical importance of p53.

Relationship of DNA ploidy and S-phase fraction to survival after first recurrence of breast cancer

Flow cytometry was performed on frozen specimens from the primary tumour of 184 women with recurrent breast cancer. No significant association was seen between DNA ploidy and the other prognostic factors investigated. Patients with a high S-phase fraction had more often a negative estrogen receptor (ER) status and a short disease-free interval. A shorter survival after disease recurrence was seen both in patients with DNA aneuploid tumours and among those with a high S-phase fraction. Patients with DNA tetraploid tumours showed the longest survival after recurrence. In this subgroup, half of the patients survived more than 3 years after recurrence and the estimated survival rate at 10 years was 17%. In a Cox's regression analysis including 116 patients, site of recurrence, number of positive nodes at time of primary operation, size and ER content of the primary tumour as well as DNA ploidy showed additional prognostic value.