Percentage Of Ki-67 Positive Cells Research Articles

INTRACELLULAR CALCIUM AND BREAST-CANCER CELL-GROWTH AND DIFFERENTIATION

The growth of normal human breast epithelial cells in vitro, as well as those of other cell types is strongly influenced by the concentration of calcium in the culture medium [Ca++]e. The aim of this study was to ascertain if calcium also affects breast tumor cell growth in vitro. To address this question, the metastatic breast cancer cells MCF-7 were grown at low (0.04 mM, L-Ca) and high (2.5 mM, H-Ca) [Ca++]e. In each culture condition, we estimated intracellular calcium levels (Ca++]i from Indo-1 fluorescence by the ratio method. We showed that [Ca++]i increased with [Ca++]e, the [Ca++]i values ranging from approximately 50 to 250 nM. Changes of [Ca++]i ware accompanied by changes of cell shape and cell kinetic parameters. In H-Ca, cells were flat and 3 times larger than in L-Ca and the percentage of cells in the S+G2+M phases as well as the percentage of Ki-67 positive cells rapidly dropped on days 3-4 of culture in contrast to cells grown in L-Ca. In H-Ca, the cell growth arrest corresponded to maximal [Ca++]i which was stable during the stationary phase; at that time, a switch from H-Ca to L-Ca resulted in a drop of [Ca++]i and a resumption of cell growth.. In H-Ca, modifications in cell differentiation parameters such as diminution of ER expression and increases of lipid content and EMA expression were observed as compared to cells grown m L-Ca. Our results suggest that MCF-7 cells have retained some calcium dependency and that agents that can increase [Ca++]i in breast tumor cells may limit their proliferation and trigger at least a partial differentiation.

Cell proliferation of breast cancer evaluated by anti-BrdU and anti-Ki-67 antibodies: Its prognostic value on short-term recurrences

The prognostic value of breast cancer proliferative activity was evaluated in 385 women operated for primary, non-metastasised mammary carcinoma. Cell kinetics was measured using two immunohistochemical techniques. Cells in S-phase of cell cycle were labelled in vitro by incubation of fresh tissue fragments with 5-bromo 2-deoxyuridine (BrdU), a thymidine analogue. Nuclei of cells in active DNA synthesis were stained by an anti-BrdU monoclonal antibody (Mab). Cells in interphase and mitosis were detected with Ki-67, a Mab that is known to react with a nuclear antigen present in G1/S/G2/M phases of cell cycle, but not in resting cells. This reagent provides a means of evaluating the growth fraction of neoplastic cells. BrdU was incorporated in a proportion of tumour cells ranging from 0.1 to 65.5% (median 6.8%). In the panel of tumours presented in this report the median percentage of Ki-67 positive cells (Ki-67 score) was 9.0% (range 0.1–77%). The relationship between disease-free survival (DFS), BrdU labelling index, Ki-67 score and 13 different clinico-pathological variables was investigated by multivariate analysis, using the Cox proportional hazards model. Axillary node status ( P = 0.009) and Ki-67 score ( P = 0.038) emerged as independent prognostic factors. Nodal status and tumour growth fraction allowed division of patients into groups at different risk of relapse: tumours with a proliferative index below the median value showed a lower recurrence rate than tumours with a high proliferative activity ( P < 0.001). In particular, no relapse occurred in pN0 patients bearing carcinomas with a Ki-67 labelling < 9.0% 4 years after surgery. These findings suggest that the evaluation of proliferative activity in breast cancer enhances the probability of correctly predicting outcome after surgery and could be of assistance in the planning of adjuvant therapies.

Expression of Ki-67 nuclear antigen in B and T cell lymphoproliferative disorders.

To determine whether the proliferation rates of tumour cells may relate to prognosis and reflect disease activity. Blood mononuclear cells from 155 patients with B cell (n = 120) or T cell (n = 35) chronic lymphoproliferative disorders were tested with the monoclonal antibody Ki-67 by indirect immunoperoxidase or immunoalkaline phosphatase techniques. B cell diseases included chronic lymphocytic leukaemia (CLL), CLL in prolymphocytic transformation (CLL/PL), prolymphocytic leukaemia (B-PLL) and non-Hodgkin's lymphoma (B-NHL) in leukaemic phase. The T cell diseases comprised large granular lymphocyte (LGL) leukaemia, T-PLL, and T-NHL. These showed significantly higher proportions of Ki-67 positive cells in T cell (11.2%) than in B cell (2.9%) disorders (p < 0.001). The highest values were found in NHL of both B and T cell types, particularly when low grade disease transformed to high grade. The lowest percentages of Ki-67 positive cells were found in CLL (1.4%) and LGL leukaemia (1.7%); intermediate values were seen in B PLL (3.3%) and T PLL (5.8%). There is a positive correlation between prognosis and proliferation rates in chronic B and T cell lymphoproliferative disorders. Estimation of Ki-67 in circulating leukaemic cells could be used to determine prognosis in low grade malignancies.

Fetal-maternal amino acid relationship in normal and intrauterine growth retarded (IUGR) pregnancies

Substaging using molecular markers has been proposed to try to identify prognostic factors allowing to define groups of patients with lung cancer for whom specific therapy might be of benefit. The pre-operative assessment of these markers seems to be important specially in case of neoadjuvant chemotherapy.The aim of our study was to compare the expression of two potential prognostic factors (p53 and Ki-67) and two potential therapeutic targets (EGF-R and c-erbB-2) assessed on biopsy samples (B) of non-small cell lung cancer (NSCLC) with that of the corresponding resected tumor (RT). The expression of these biological markers was evaluated by immunohistochemistry on B and on the paired RT in 28 patients.The mean percentage of p53 positive cells was 28% in RT and 38% in B with 81% CR between B and RT and 19% FP on B. Considering RT results as standard, the positive (PPV) and negative predictive value (NPV) of the B were, respectively, 74 and 100%. The mean percentage of EGF-R positive cells was 11% in RT and 28% in B. With a cut-off of 1%, we found 85% concordant results (CR) between B and RT, 4% false negative (FN) and 11% false positive (FP) on B. The PPV and NPV values of the B were, respectively, 80 and 92%. The 8% B and 19% RT were considered as positive for c-erbB-2. We found 15% FN and 4% FP on B with 81% CR between B and RT for c-erbB-2. The NPV of the B was 83%. The mean percentage of Ki-67 positive cells was 32% in RT and 14% in B. We found 82% CR between B and RT, 14% FN and 4% FP on B. The PPV of the B was 96%.In conclusion, biopsies may provide reliable information about p53, EGF-R, c-erbB-2 and Ki-67 in lung carcinoma and could help to elaborate a therapeutic strategy.

Cell proliferation in serial biopsies through human malignant brain tumours: Measurement using Ki67 antibody labelling

Cell proliferation was assessed in brain tumours using the monoclonal antibody Ki67 which recognizes a nuclear antigen expressed by proliferating cells. Using a novel stereotactic biopsy procedure, serial 1 cm biopsies were taken along a trajectory through six malignant brain tumours. Specimens were also obtained from 10 other brain tumours during conventional surgery. The percentage of Ki67 positive cells was determined as a fraction of the total number of tumour cells present. The Ki67 index for anaplastic astrocytomas and glioblastomas was significantly higher (Ki67 index range 11-18%) than that for benign or low grade tumours. Significant variation in proliferation was measured along the biopsy track through individual tumours (e.g. 0-12.3%) which correlated well with histological appearance. The Ki67 indices of normal brain were very low. In general the Ki67 indices increased with increasing histological grade and also appear to be a useful indicator of the active tumour volume and margin. This method provides spatial information about tumour proliferation which may be used to decide between different treatments and relate to prognosis.

Correlation between nucleolar organizer region staining and Ki-67 immunostaining in human gliomas

Fourteen cases of various grades of gliomas were investigated by an immunohistochemical method using a monoclonal antibody, Ki-67, which reacted with a nuclear antigen in proliferating cells, and the correlation between Ki-67 labeling index and the number of nucleolar organizer regions stained by an argyrophilic method. Four normal brain tissue samples without neoplastic cells, which were obtained at surgery, were also examined for nucleolar organizer region staining. Both the mean number of nucleolar organizer regions and the percentage of Ki-67 positive cells well reflected the histological grade of gliomas (astrocytoma grade 2: Ki-67, 0.5% and nucleolar organizer regions, 1.6; astrocytoma grade 3: Ki-67, 3% and nucleolar organizer regions, 2.5; astrocytoma grade 4: Ki-67, 5.2% and nucleolar organizer regions, 2.8). Also, the percentage of Ki-67 positive cells and the mean number of nucleolar organizer regions were found to be linearly related ( r = 0.91). Both values of high-grade astrocytomas were significantly greater than those of low-grade astrocytomas ( p < 0.01 and p < 0.001). Thus, the mean number of nucleolar organizer regions as well as Ki-67 labeling index reflect the proliferating potential of gliomas.

Growth fractions of breast cancer in relation to epidermal growth factor receptor and estrogen receptor

Growth fractions detected by a monoclonal antibody, Ki-67, were examined in 40 human breast cancer tissues and the results compared with the immunocytochemical reactivities of epidermal growth factor receptor (EGFR) and estrogen receptor (ER). The proportion of proliferating cells displaying Ki-67 positive staining was significantly higher in the EGFR positive tumors than in the EGFR negative tumors (p less than 0.01). The average percentage of Ki-67 positive cells in the EGFR positive tumors was 19.9 per cent, whereas that in the EGFR negative tumors was 8.0 per cent. By contrast, an inverse relationship between the proportion of proliferating cells and ER positive cells detected by anti-ER monoclonal antibody was observed. This data indicated the difference in growth fractions with relation to the EGFR and ER status of breast cancer.

Ki-67 labeling index in breast cancer.

Measurements of cell cycle kinetics have been found to correlate with the clinical course of patients with breast cancer. However, the thymidine labeling index and more rapid methods like flow cytometry remain complicated and costly. We assessed cell proliferation of 67 breast carcinomas by an immunoperoxidase procedure using a monoclonal antibody, Ki-67, which reacts with a nuclear antigen in proliferating cells. The percentage of Ki-67 positive cells ranged from 2% to 70%. Tumors with high mitotic rate, high nuclear grade, high histologic grade, and negative estrogen receptors had statistically higher Ki-67 labeling rates. We found no significant differences between the Ki-67 labeling rate and other clinical (age at diagnosis, menopausal status) or pathologic (necrosis, fibrosis, vascular invasion, lymphatic invasion, cellular reaction, tumor size, lymph node metastases) features assessed. These results parallel previously reported data, and confirm that this immunohistochemical staining of breast carcinoma by Ki-67 monoclonal antibody can be considered a rapid and convenient method for assessing cell cycle kinetics. However, further studies, evaluating the correlation between Ki-67 labeling rate and prognosis are needed to better define the real usefulness of this analysis in clinical practice.

The monoclonal antibody Ki-67 as a marker for proliferating cells in stereotactic biopsies of brain tumours

The monoclonal antibody Ki-67 has been tested as a marker of proliferating cells in 52 stereotactic brain tumour biopsies. The antibody reacts with a nuclear protein expressed in G1,S, G2n and M-phases of the cell cycle. Using the immunoperoxidase technique on squash preparations the percentage of Ki-67 positive cells was determined as a fraction of the total number of tumour cells present. This Ki-67 index was in close correlation with the histological grade. Highest values were found in a pineal germinoma (46.3%) and in 3 primary cerebral non-Hodgkin lymphomas (mean 39.5%). Among the gliomas, the highest fraction of proliferating cells was seen in 2 anaplastic paediatric brain stem gliomas (mean 17.4%) and in an anaplastic ependymoma (12.5%). Anaplastic astrocytomas and glioblastomas varied considerably with mean values of 9.5% and 8%, respectively. To some extent this variability may reflect tumour heterogeneity which is more likely to manifest in small stereotactic samples than in large tissue specimens obtained during open surgery. Pilocytic astrocytomas, mixed gliomas and fibrillary astrocytomas had moderate to low percentages. Ki-67 staining of squash preparations can easily be performed on a routine basis and is, in our experience, superior to frozen sections. This method allows the determination of the growth fraction of an individual tumour and could become an important additional criterion for the decision among alternative and potentially harmful therapeutic regimens.

Determination of the growth fraction in cell suspensions by flow cytometry using the monoclonal antibody Ki-67

A novel procedure for determining the growth fraction of cell suspensions by flow cytometry is described. This method identifies proliferating cells by binding the monoclonal antibody Ki-67 to a nuclear antigen present in all cells that are in the G1, S, G2, and M phase of the cell cycle, but not in the G0 phase. In a kinetic study of Na cell line U937 using concanavalin A for stimulation of peripheral blood mononuclear cells, a steady increase of Ki-67 positive cells evaluated by flow cytometry was observed. Simultaneously, the [ 3H]thymidine uptake of the ConA blasts was measured and compared to the expression of Ki-67. A linear correlation between the percentage of Ki-67 positive cells and the log transformed counts per minute was demonstrated, and staining with Ki-67 detected cell proliferation with the same sensitivity as 3H-TdR uptake. In addition, it was possible to stain Ki-67-labelled cells with a second cell marker if a second fluorescent dye coupled to an antibody was used. This provided the opportunity to define precisely the phenotype of proliferating cells. Conversely, the number of proliferating cells expressing certain preselected surface markers could be easily determined.

Growth fractions in malignant non-Hodgkin's lymphomas (NHL) as determined in situ with the monoclonal antibody Ki-67.

The proportion of proliferating cells in malignant non-Hodgkin's lymphomas (NHL) was determined in situ by immunostaining with the monoclonal antibody Ki-67, which reacts with a nuclear antigen that is present only in proliferating cells. A highly significant correlation could be demonstrated between the proportion of Ki-67 positive cells and the classification into high and low-grade NHL according to the Kiel classification. 93.8 per cent of high-grade and 88.5 per cent of low-grade malignancies were correctly allocated to these groups using the percentage of Ki-67 positive cells as discriminant parameter. On the basis of the medians, the degree of proliferation also paralleled the succession of entities within the Kiel classification. Within most of these different entities, however, the ranges of Ki-67 positive cells varied considerably, indicating that the growth fractions within these groups are rather heterogeneous. Thus it might be useful to determine the growth fraction of each individual case of NHL, because this might be of prognostic value.