Biomedical subjects

B Baldetorp

Publications and source records attributed to B Baldetorp.

At least 37 records · Page 2Linked to original sources

PubMed1998

Genetic aberrations in hypodiploid breast cancer: frequent loss of chromosome 4 and amplification of cyclin D1 oncogene.

The evolution of somatic genetic aberrations in breast cancer has remained poorly understood. The most common chromosomal abnormality is hyperdiploidy, which is thought to arise via a transient hypodiploid state. However, hypodiploidy persists in 1 to 2% of breast tumors, which are characterized by a poor prognosis. We studied the genetic aberrations in 15 flow cytometrically hypodiploid breast cancers by comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH). Surprisingly, numerous copy number gains were detected in addition to the copy number losses. The number of gains per tumor was 4.3 +/- 3.2 and that of losses was 4.5 +/- 3.3 (mean +/- SD), which is similar to that previously observed in hyperdiploid breast cancers. Gains at chromosomes or chromosomal regions at 11q13, 1q, 19, and 16p and losses of 2q, 4, 6q, 9p, 13, and 18 were most commonly observed. Compared with unselected breast carcinomas, hypodiploid tumors showed certain differences. Loss of chromosome 4 (53%) and gain of 11q13 (60%) were significantly more common in hypodiploid tumors. The gain at 11q13 was found by FISH to harbor amplification of the Cyclin D1 oncogene, which is therefore three to four times more common in hypodiploid than in unselected breast cancers (15 to 20%). Structural chromosomal aberrations (such as Cyclin D1 amplification) were present both in diploid and hypodiploid tumor cell populations, as assessed by FISH and CGH after flow cytometric sorting. Together these results indicate that hypodiploid tumors form a distinct genetic entity of invasive breast cancer, although they probably share a common genetic evolution pathway where structural chromosomal aberrations precede gross DNA ploidy changes.

Adult↗

PubMed1998

Complex karyotypes in flow cytometrically DNA-diploid squamous cell carcinomas of the head and neck.

In squamous cell carcinoma of the head and neck (SCCHN), DNA ploidy as determined by flow cytometry (FCM) has been found to yield prognostic information but only for tumours at oral sites. Cytogenetic findings have indicated complex karyotype to be a correlate of poor clinical outcome. In the present study, 73 SCCHN were investigated with the two techniques. Aneuploid cell populations were identified in 49 (67%) cases by FCM but in only 21 (29%) cases by cytogenetic analysis. The chromosome index (CI), calculated as the mean chromosome number divided by 46, was compared with the respective DNA index (DI) obtained by FCM in 15 tumours, non-diploid according to both techniques, DI being systematically 12% higher than CI in this subgroup. Eight (33%) of the 24 tumours diploid according to FCM had complex karyotypes, three of the tumours being cytogenetically hypodiploid, three diploid and two non-diploid. The findings in the present study may partly explain the low prognostic value of ploidy status as assessed by FCM that has been observed in SCCHN. In addition, we conclude that FCM yields information of the genetic changes that is too unspecific, and that cytogenetic analysis shows a high rate of unsuccessful investigations, thus diminishing the value of the two methods as prognostic factors in SCCHN.

Adult↗

PubMed1998

Proliferative index obtained by DNA image cytometry. Does it add prognostic information in Auer IV breast cancer?

OBJECTIVE: To investigate whether the S + G2/M fraction (proliferative index) is a prognostic determinant in breast cancers classified as Auer IV. STUDY DESIGN: Prognostic evaluation of Auer IV DNA histograms with respect to the high versus low S + G2/M fraction, obtained by image cytometry on consecutive breast cancer imprint preparations. RESULTS: When studying recurrence-free survival (n = 136), the prognostic value of S + G2/M was found to vary with time: it was negligible before the median time to relapse (1.5 years) but thereafter statistically significant, in both univariate and multivariate analysis. The same pattern was found when overall survival was used as the end point; the effect was delayed to about the median time until death (three years). Tumors with a low S + G2/M fraction were smaller and more often estrogen receptor- and progesterone receptor-positive than those with a high S + G2/M fraction. CONCLUSION: According to ICM-DNA values corresponding to the S + G2/M region, patients with breast cancers classified as Auer IV can be divided into subgroups with different tumor characteristics and prognoses.

Breast Neoplasms↗

PubMed1998

p53-dependent and -independent differentiation of leukemic U-937 cells: relationship to cell cycle control.

Observations based on overexpression of the suppressor gene p53 or interference with endogenous p53 support a role for p53 in mediating not only growth inhibition and apoptosis but also differentiation. The aim of this study was to characterize the mechanisms of p53-dependent differentiation in the monoblastic leukemia cell line U-937. These cells were transfected with a mutant of the p53 gene expressing wild-type p53 at a permissive temperature. The results showed that wild-type p53 and interferon (IFN)-gamma were able to work synergistically to promote differentiation. This cooperative response was not associated with early G1 arrest of the cell cycle, indicating that p53 can mediate differentiation by mechanisms other than those used for mediating G1 arrest. The differentiation response to transfected p53 with or without INF-gamma was inhibited by cyclic adenosine monophosphate (cAMP)-inducing agents (dibutyryl cyclic adenosine 3':5'-monophosphate, forskolin, and 3-isobutyl-1-methylxanthine) in a dose-dependent manner. In contrast, the differentiation response of p53-negative U-937 cells to 1,25-dihydroxychole-calciferol or all-trans retinoic acid was enhanced by cAMP-inducing agents at optimal concentrations and inhibited at higher concentrations. In addition, 1,25-dihydroxycholecalciferol-mediated differentiation could be achieved in cells arrested in G1 by concomitant incubation with cAMP-inducing agents, indicating that differentiation can occur in the absence of proliferation. In conclusion, the results of this study indicate that p53-dependent and -independent differentiation can occur independently of cell cycle regulation.

1-Methyl-3-isobutylxanthine↗

PubMed1997

Activated cell cycle checkpoints in epirubicin-treated breast cancer cells studied by BrdUrd-flow cytometry.

Genetic alterations, such as p53 mutations, may affect a tumour's response to chemotherapy. We have treated two human breast cancer cell lines that differ in p53 status with epirubicin in order to study if there are differences in cell cycle kinetic response. MCF-7 cells express wild-type p53, while SK-BR-3 cells express only a mutated form of p53. The transition of cells from one cell cycle stage to another was studied by a bromodeoxyuridine (BrdUrd)-flow cytometry (FCM) method. MCF-7 cells showed a block in the G1 phase after treatment with 50 nM epirubicin for 24 hours, in agreement with the actions of p53 at the G1 checkpoint. SK-BR-3 cells, on the other hand, progressed through the G1 checkpoint and were blocked in late S and G2 phases, presumably due to the activation of a later checkpoint. In addition, studies of the mRNA levels of p53 and its effector gene p21 revealed that although both cell lines expressed p53 mRNA, a marked difference in the mRNA levels of p21 was seen. A dramatic increase in the level of p21 mRNA was seen in epirubicin-treated MCF-7 cells, while no such increase was seen in SK-BR-3 cells.

Antibiotics, Antineoplastic↗

PubMed1997

Altered expression of the retinoblastoma tumor-suppressor gene in leukemic cell lines inhibits induction of differentiation but not G1-accumulation.

The retinoblastoma tumor-suppressor gene, RB, has been implicated in tumor suppression, in regulation of the cell cycle, and in mediating cell differentiation. RB is necessary for hematopoiesis in mice, and aberrant RB-expression is associated with the progress and prognosis of leukemia. We have used antisense oligonucleotides, established clones stably expressing an antisense RB construct, and also established clones over expressing the retinoblastoma protein (pRb) to study the role of RB expression in monocytic differentiation induced by all-trans retinoic acid (ATRA) or 1-alpha-25-dihyroxycholecalciferol (Vit D3) in the monoblastic cell line U-937 and erythroid differentiation induced by transforming growth factor beta1 (TGFbeta1) and hemin in the erythroleukemic cell line K562. A reduction in pRb production in antisense RB-transfected U-937 clones was shown. Antisense oligonucleotides as well as expression of the antisense RB construct suppressed differentiation responses to ATRA or Vit D3, as judged by the capability to reduce nitro blue tetrazolium, by the appearance of monocyte-related cell surface antigens and by morphologic criteria. K562 cells showed decreased differentiation response to TGFbeta1, but not to hemin, when incubated with antisense oligonucleotides. U-937 antisense RB-transfected cells were also suppressed in their ability to upregulate levels of hypophosphorylated pRb when induced to differentiate. Although U-937 cells incubated with antisense oligonucleotides and clones expressing the antisense RB construct were hampered in their ability to differentiate on incubation with ATRA or Vit D3, the induced G0/G1-accumulation was similar to differentiating control cells treated with ATRA or Vit D3. Intriguingly, U-937 clones overexpressing RB were also inhibited in their differentiation response to ATRA or Vit D3 but not inhibited in their ability to respond with G0/G1 accumulation when induced with these substances. The results indicate that pRb plays a role in induced differentiation of U-937 cells as well as K562 cells involving mechanisms that, at least partially, are distinct from those inducing G1 accumulation.

Animals↗

PubMed1997

Flow cytometric S-phase fraction in soft-tissue sarcoma: prognostic importance analysed in 160 patients.

We could determine the S-phase fraction (SPF) by flow cytometric DNA analysis of paraffin archival material in 160 of 260 patients with soft-tissue sarcoma of extremity and trunk wall. The prognostic value of SPF was compared with other clinicopathological factors. The median follow-up time was 16 (6-31) years. In a univariate analysis, deep tumour location, increasing tumour size and histological malignancy grade, microscopic tumour necrosis, vascular invasion, DNA non-diploidy and high SPF (>3.0%) were associated with poor metastasis-free survival. In a multivariate analysis, microscopic tumour necrosis and high SPF were independently prognostic for metastasis. Used in combination with tumour size, microscopic tumour necrosis and vascular invasion, SPF could identify a group of patients with a 5-year metastasis-free survival rate of 0.97. This group constituted one-quarter of all patients. Patients with low SPF who did recur had a prolonged clinical course both as regards metastases and local recurrence. We conclude that SPF is a valuable adjunct in prognostication in soft-tissue sarcoma.

Adolescent↗

PubMed1997

DNA ploidy analysis in breast carcinoma. Comparison of unfixed and fixed tissue analyzed by image and flow cytometry.

OBJECTIVE: To form a methodologic basis for DNA analysis of ductal carcinoma in situ (DCIS) and invasive carcinoma (IC) of the breast, including very small lesions, by comparison of flow cytometric (FCM) and image cytometric (ICM) methods for DNA quantitation. STUDY DESIGN: The material consisted of 41 DCIS lesions and 26 ICs. FCM DNA analysis of unfixed, frozen samples were compared to (1) FCM of formalin-fixed, paraffin-embedded tissue; (2) ICM of imprints; and (3) ICM of paraffin-embedded tissue sections. RESULTS: FCM of unfixed tissue showed higher DNA measurement precision and a higher number of DNA nondiploid clones as compared to the other three methods. For the classification of DNA diploid/nondiploid cases, high concordance rates were found between the methods. Discordant cases were predominantly DNA neardiploid by FCM of unfixed tissue but DNA diploid by the other methods. The reproducibility of the DNA index (DI) was best in the interval 1.2 < DI < or = 2.2; it was 74% for FCM of fixed tissue and 79% for ICM of imprints. Clones with DI > 3 were found almost exclusively by ICM of imprints. For ICM of tissue sections, DI could not be reliably estimated. By ICM, contrary to FCM, a combined DNA diploid and nondiploid pattern was found frequently. CONCLUSION: Each of the methods has its own advantages and limitations. If possible, FCM should be combined with ICM. FCM of unfixed tissue is superior to the other methods with respect to precise DI estimation. Alternatively, FCM of fixed tissue and ICM of imprints may both give a reliable estimate of DI. ICM of tissue sections can discriminate DNA diploid from nondiploid clones, except for neardiploid subpopulations, and permits the analysis of very small lesions.

Breast Neoplasms↗

PubMed1996

Expression of the p53 tumor suppressor gene induces differentiation and promotes induction of differentiation by 1,25-dihydroxycholecalciferol in leukemic U-937 cells.

Leukemic U-937 cells, which lack normal p53, were stably transfected with a temperature-sensitive mutant of p53 to investigate the consequences for growth and differentiation. On induction of wild-type p53 activity at the permissive temperature, some of these cells underwent maturation as judged by the capacity for oxidative burst and the appearance of monocyte related cell surface molecules. Moreover, wild-type p53-expressing cells were more sensitive than p53-negative control cells to induction of differentiation by 1,25-dihydroxycholecalciferol; a twofold to fourfold increase of the fraction of cells showing signs of terminal maturation was observed when wild-type p53-expressing cells were incubated with 1,25-dihydroxycholecalciferol at concentrations that only slightly affected control cells. Whereas wild-type p53 activity per se induced maturation of certain cells, other underwent cell death judging from the reduced capability to exclude trypan blue and the appearance of fragmented DNA in flow cytometric analysis. The p53-induced cell death could be inhibited by incubation with 1,25-dihydroxy-cholecalciferol, but not all-trans retinoic acid. Thus, 1,25-dihydroxycholecalciferol, seemed to increase the survival of wild-type p53-expressing cells and to cooperate with wild-type p53 to induce differentiation. The data imply that p53-mediated maturation in U-937 cells depends on optimal regulation of signals for differentiation, survival and proliferation, and suggest a role for p53 in the differentiation induction of leukemic cells.

Apoptosis↗

PubMed1996

Metaphase cytogenetics and DNA flow cytometry with analysis of S-phase fraction in prostate cancer: influence on prognosis.

OBJECTIVES: To compare the prognostic significance of chromosome aberrations, DNA ploidy, and S-phase fraction (SPF) in prostate adenocarcinomas and to compare the sensitivity of metaphase cytogenetics with flow cytometry (FCM) in detecting abnormal tumor clones. METHODS: Prostate adenocarcinomas from 57 men were previously successfully analyzed with metaphase cytogenetics. Archival material from these tumors were further analyzed with FCM for DNA content and SPF. RESULTS: The patients were followed for 4.5 to 7.7 years. DNA ploidy was analyzed in 51, and SPF in 45 of the 57 tumors. Clonal chromosomal aberrations, DNA aneuploidy, and high SPF were all significantly associated with poor survival. Of these three variables, SPF was the best predictor of survival, but compared with tumor stage and grade in multivariate analysis, SPF was not an independent prognostic factor. Patients with locally advanced tumors or metastatic disease with SPF less than 8% had a median survival of 5.9 years, compared with only 1.3 years for those with SPF more than 8%. Twenty-eight abnormal clones were detected with FCM and 20 with cytogenetic analysis, but only for two of these clones could the results from the two different methods be regarded as concordant. CONCLUSIONS: SPF was superior to karyotype and ploidy in predicting death in prostate cancer, but it remains to be shown whether SPF analysis adds prognostic information to tumor stage and grade. The cytogenetic analyses correlated poorly with results of FCM, indicating low sensitivity of both methods.

Adenocarcinoma↗

PubMed1996

Impedance spectra of tumour tissue in comparison with normal tissue; a possible clinical application for electrical impedance tomography.

Electrical characteristics of living tissues have been investigated for a long time in the search for further methods to complement the traditional investigations of pathology and physiology. Tumour tissue has been shown to exhibit a larger permittivity and conductivity than normal tissues. This might be associated with the fact that tumour cells have a higher water content and sodium concentration than normal cells, as well as different electrochemical properties of their cell membranes. To our knowledge only a few contributions on this subject have been published. This study describes an additional application on measurements of the complex impedance of tumour and normal tissues, in order to compare the impedance features of the two tissue types. The tissue sample is placed in a measuring cell in which the temperature is controlled. The measuring cell is connected to an impedance meter able to measure the complex impedance in terms of real and imaginary part curves for frequencies from 1.5 kHz to 700 kHz. The four-electrode principle is used with the current injected by the outer electrodes and the voltage difference measured between the inner electrodes. The current can be altered up to 1 mA. The instrument can be calibrated with known resistance and capacitance networks connected to the input of the instrument in order to minimize the measurement errors. The calibration routine uses a polynomial adaptation and can be applied interactively. Measurements performed by the instrument show promising results. Preliminary results show that this method can be extended to a new application for detection of tumour tissue by electrical impedance tomography (EIT).

Animals↗

PubMed1996

Flow cytometric DNA analysis in endometriotic tissue compared to normal uterine endometrium.

Endometriotic tissue sometimes shows an invasive pattern. but the growth regulation of the tissue is insufficiently characterized. In a research programme on factors regulating endometriotic growth, the DNA ploidy status and S-phase fraction (SPF) were studied. Fresh-frozen endometriotic tissue from 14 women and endometrium from 11 of them were studied using flow cytometry. A clear diploid pattern was seen in most cases of endometriotic (8/14) and endometrial (8/11) samples. In the remaining cases the G0/G1 peak was broad and skewed, which might indicate a near-diploid cell population. To clarify this, a second group was studied, consisting of 29 formalin-fixed endometriotic samples from 22 women and endometrium from five of them. All these samples were diploid, with one having a broad G0/G1 peak. No convincing difference in SPF between endometrium and endometriotic tissue was found, as the calculations had to be handled with caution because of debris in many samples. Although the study of fresh-frozen samples gave some indications of differences in DNA ploidy status, flow of cytometric DNA analysis of formalin fixed samples of endometriosis showed a diploid DNA pattern in all samples. In conclusion, DNA flow cytometry did not show a convincing aneuploid DNA pattern in endometriotic tissue.

DNA↗

PubMed1996

Comparison of mathematical formulas used for estimation of DNA synthesis time of bromodeoxyuridine-labelled cell populations with different proliferative characteristics.

Growth kinetic data of human tumours, obtained by flow cytometric analysis of cells labelled with bromodeoxyuridine (BrdUrd) might provide prognostic information and allow prediction of response to radio- and chemotherapy. However, the theoretical models applied for calculation of growth kinetic data are not fully evaluated. The purpose of this study was to investigate the dependence of the estimation of DNA synthesis time (Ts) on sampling time after BrdUrd labelling, using four different mathematical formulas (Begg et al., White & Meistrich, White et al. and Johansson et al.) which have been developed for the evaluation of flow cytometry-derived data of BrdUrd-labelled cells. In addition, we have investigated the influence of the growth kinetic properties of the cell populations using two cultured cell lines (one slow and one fast growing), and two hetero-transplanted human tumours. The dependence of the estimation of Ts on sampling time was more or less pronounced, depending on the cell population examined and on the formula used. In the fast growing cell line, the estimates of Ts did not vary significantly with sampling time when using the formulas by White et al., whereas in the slow growing cell line, the estimates of Ts did not show any significant dependence on sampling time when using the formula by Johansson et al. In the tumours, the estimation of Ts depended on sampling time with all formulas used, although to different degrees. In one of the tumours, this was mainly caused by the influence of mouse cells, as we demonstrate. Our results indicate that the proliferative characteristics of a cell population should be taken into consideration when choosing a mathematical formula in order to attain Ts values that are independent of sampling time.

Adenocarcinoma↗

PubMed1996

Preoperative fine needle aspiration from human breast cancer is a valuable sampling material for progesterone receptor and cytometric DNA analysis.

In a breast cancer series (n = 54), preoperative fine needle aspiration (FNA) was compared with biopsy at primary surgery as a source of material for the determination of progesterone receptor (PgR) content by enzyme immuno assay. The respective results manifested a strong correlation (r(s) = 0.82). The fact that PgR content was usually higher in FNA samples than in the corresponding biopsy samples and the finding that 11% of the tumours were PgR positive in FNA but PgR negative in the corresponding biopsy samples suggest a greater proportion of malignant cells to be obtained with FNA than in surgical biopsy. In another breast cancer series (n = 50), corresponding comparisons for DNA flow cytometry showed concordance in ploidy status (diploid vs. non-diploid) in 84% of cases and a strong correlation in S-phase fraction values (r(s) = 0.70). At DNA image cytometry, concordant results (Auer I + II vs. Auer III + IV) were obtained in 87% of the cases. To sum up, FNA seems to be a useful sampling technique for PgR determination and DNA cytometry.

Aneuploidy↗

PubMed1996

Methodological aspects of flow cytometry DNA analysis in endometrial carcinoma, with special reference to sampling and reproducibility.

Two adjacent paraffin-embedded sections manifested concordance in ploidy status in 96% of cases (45/47), and the standard deviation (SD) for SPF was 2.7%. Analysis of 'micro-heterogeneity', within a distance of < or = 700 microm, yielded results for concordant ploidy status in 94% of cases, and the SD for SPF was 1.9% (n = 17). Frozen and paraffin-embedded material yielded concordant results for ploidy status in 87% (39/45) of cases, and SPF values were significantly lower (mean difference 1.5%) in the frozen samples. Diagnostic and repeat curettage material yielded concordant results for DNA ploidy status in 85% (40/47) of cases, and no significant difference in mean SPF (12% vs. 11%) was found. Discordant DNA ploidy results were attributable to small differences in the DNA histograms influencing the interpretation of near-diploid, near-tetraploid and small non-diploid cell populations, and the influence of debris on SPF estimation. On the basis of our findings and the practical advantage we recommend paraffin-embedded material from diagnostic curettage for FCM DNA analysis; the results are available sooner and the handling and transportation of tumor samples is more convenient.

Cryopreservation↗

PubMed1996

Flow cytometry analysis of malignant tumors of the head and neck--differences between two methods in the recognition of aneuploidy.

DNA aneuploidy, which reflects changes in nuclear DNA-content, as determined cytometrically is a candidate prognostic factor in squamous cell carcinoma of the head and neck. The aim of this study was to compare two different preparation methods with respect to their use in detecting aneuploid tumor cell populations in malignant tumors of the head and neck. Fresh frozen tumor material was used. The methods compared were a multistep procedure (A) including fixation of cells and enzymatic treatment, and a one step procedure (B). Both include RNAse and the use of propidium iodide for DNA staining. Forty-seven percent of the tumors were non-diploid according to method A, and 29% according to method B, discordant findings being made in 15 tumors, only two of which were non-SCC. Defining a 'true non-diploid tumor' in this series as a tumor with a DNA index outside the range of diploidy detected either by method A or B, 59% (29/49) of the tumors were non-diploid. The sensitivity was 0.48 (14/29) for method B and 0.79 (23/29) for method A. The striking differences in accuracy between methods A and B emphasize the need of caution when new methods are introduced, and when results obtained with different methods are compared.

Analysis of Variance↗

PubMed1995

Reproducibility in DNA flow cytometric analysis of breast cancer: comparison of 12 laboratories' results for 67 sample homogenates.

Flow cytometric (FCM) DNA analysis yields information on ploidy status and the S-phase fraction (SPF), variables of prognostic importance in breast cancer. The clinical value of the SPF is currently being evaluated in prospective randomized trials. The widespread use of FCM DNA analysis emphasizes the importance of reproducibility (both intra- and interlaboratory). In this study, 67 nuclear suspensions of breast cancer samples were analyzed by 12 laboratories routinely performing FCM DNA analysis in breast cancer. No general guidelines were imposed; each laboratory used its own standard protocols. For DNA ploidy status (diploid vs. non-diploid), agreement was complete for 79% (53/67) of the samples, compared with 64% (43/67) of samples when tetraploidy was considered [i.e., euploid (diploid+tetraploid) vs. aneuploid (the remaining non-diploid)]. For the SPF, pairwise comparison of the results of all 12 laboratories yielded a mean Spearman's rank correlation of 0.78 (range: 0.54-0.93). For those 39 samples being categorized in low or high SPF by all laboratories, all agreed in 14 samples (36%). Similar patterns were obtained with kappa measures, agreement being good for ploidy status (diploid vs. non-diploid; overall kappa = 0.87 and 0.74 for euploid vs. aneuploid), but moderate for the SPF [overall kappa = 0.47 (for low SPF vs. high SPF vs. "no SPF reported")]. Discrepancies were chiefly attributable to differences in the categorization of the S-phase values, rather than in FCM procedures, other critical differences being in the detection and interpretation of near-diploid and small non-diploid cell populations, the definition of tetraploidy, and the choice and execution of the method used for S-phase estimation. Based on the observations of this study, detailed guidelines for FCM analysis and interpretation of data are proposed in the Appendix. Some issues remain, however, e.g., to standardize a method for S-phase calculation and tetraploid definition.

Breast Neoplasms↗

PubMed1995

Recurrence-free survival in breast cancer improved by adjuvant tamoxifen--especially for progesterone receptor positive tumors with a high proliferation.

Although the beneficial effect on breast cancer of adjuvant tamoxifen (TAM) is well established, in the series studied by our group this effect seems to have been restricted to patients with steroid receptor (especially progesterone receptor (PgR)) positive tumors. However, as some patients with PgR-positive tumors manifested recurrence despite adjuvant TAM treatment, the question arose whether some other biological factor(s) could be used to identify these non-responding cases. The level of the S-phase fraction (SPF), as measured by flow cytometry, has been shown to be a useful prognostic marker, prognosis being better in cases where the SPF is low than in those where it is high. The aim of the present study was to relate the prognosis after adjuvant TAM to SPF among patients with PgR-positive tumors. In the PgR-positive group as a whole, the effect of TAM on prognosis was more pronounced in the high SPF group than in the low SPF group (p = 0.005) the respective decrease in 3 year recurrence rate was from 19 to 43% and from 17 to 9%. Multivariate analysis of the data for the TAM-treated group showed the level of PgR concentration (low positive vs. high positive), lymph node status, and tumor size to be independent predictive factors, but not the level of SPF (i.e. high vs. low). By contrast, among patients not treated with TAM, the SPF was a strong independent prognostic factor. To sum up, SPF was a strong independent predictor of outcome only for patients receiving no systemic adjuvant therapy, but not in patients receiving adjuvant TAM. Patients with PgR-positive and high S-phase tumors derived more benefit from TAM than patients with PgR-positive and low SPF tumors.

Adult↗