Differences between labeling index and DNA histograms in assessing S-phase cells from a homogeneous group of chronic phase CML patients

Accuracy of immunohistochemistry and flow cytometry in estimating the proportion of leukemic cells in S phase in chronic myeloid leukemia patients

We compared the proportion of S phase cells in bone marrow and peripheral blood samples obtained from 17 patients with chronic myeloid leukemia (CML). Before sampling all patients received a one hour i.v. infusion of iododeoxyuridine (IdUrd). The proportion of S phase cells was studied by immunohistochemistry (IHC) in bone marrow biopsies, and by flow cytometry (FCM) in bone marrow aspirates and peripheral blood samples. The IdUrd labelling index (LI) in bone marrow biopsy sections (27.5 +/- 1.8%) was significantly higher than the proportion of IdUrd labelled cells in bone marrow aspirate (15.1 +/- 2.0%). The percentage of S phase cells in peripheral blood was approximately the same as that in the aspirate (12.4 +/- 1.3%) and was correlated with that of bone marrow aspirate indicating a high degree of the aspirate dilution by peripheral blood. It is likely that the differences in % S phase cells in the aspirate and the biopsy result from this dilution. Estimates of the % S phase cells in the peripheral blood study by IHC and FCM were essentially the same. Samples labelled for one hour in vitro resulted in 1.5 fold higher LI than the same samples labelled in vivo. We conclude that estimates of the 8% S phase cells in the bone marrow of patients with CML should be made by infusing patients with IdUrd or BrdUrd with immunohistochemical evaluation of a marrow biopsy. Additionally in vitro labelling is not reflective of the percent S phase cells in vivo in patients.

Contribution of in vivo proliferation/differentiation studies toward the development of a combined functional and morphologic system of classification of neoplastic diseases

Proliferation kinetics of both leukemia and a variety of solid tumors have been assessed after in vivo infusions of the thymidine analogues, iododeoxyuridine (IUdR) and bromodeoxyuridine (BrdU). In acute myeloid leukemia (AML), these data indicate that the pretherapy cell cycle time (Tc) of myeloblasts is a prognostic indicator for remission duration since patients with slowly cycling myeloblasts had more durable remissions. The presence of in vivo differentiation detected from the day 7 biopsy after chemotherapy was also of favorable prognosis as these individuals had statistically significant improvement in their remission duration. The data in solid tumors are not mature enough for determining their clinical significance. Since cell kinetic information is readily available in a prompt fashion using these novel techniques, data can be used to plan therapeutic strategies for patients. This review discusses the state-of-the-art techniques available for cell cycle kinetic studies and the clinical and prognostic utility of data that have been generated thus far.

Flow cytometric analysis of DNA content and keratins by using CK7, CK8, CK18, CK19, and KL1 monoclonal antibodies in benign and malignant human breast tumors

We have used a double-labelling flow cytometry analysis of keratin (CK) and DNA in breast cancer. Five monoclonal anti-keratin antibodies were tested: KL1 recognizing Mr 55,000-57,000 keratins, and "anti-glandular epithelia," LE41, RGE-53, and LP2K specific for CK n. 7, 8, 18, and 19 of Moll's classification, respectively. Flow cytometric (DNA-CK) analysis was performed on 10 benign and 19 malignant human breast tumors. All the benign tumors were diploid and 63% of the malignant tumors were aneuploid. This technique permits the analysis of DNA in the epithelial fraction alone. In aneuploid tumors, gating the DNA-keratin-positive population allowed accurate DNA analysis without interference due to debris background and non-epithelial cells. Moreover, double-labelling using the CK19 antibody gave a better identification of near-diploid tumors. An enhancement of keratin expression in malignant tumors was observed with CK 19 (P less than 0.001), KL1 (P less than 0.01), CK 8 (P less than 0.05), and CK18 (n.s.) compared to benign tumors. The comparison of keratin expression in aneuploid and diploid malignant tumors revealed reduced CK8, CK18, and CK19 in the former.

Initial and early effects of adriamycin in murine sarcoma 180 cannot be restored in a resistant subline by increasing the uptake and external concentration of the drug

We demonstrate the early effects (1 day) of Adriamycin (ADM) on proliferation-stimulated and quiescent sensitive, and ADM-resistant cells of the murine tumor sarcoma 180 (S 180). By investigating cell-cycle distribution and thymidine labeling, it can be shown that sensitive cells are strongly affected by the drug, even in a proliferationarrested state. A remarkable but slow DNA synthesis is the prominent effect of this drug treatment on sensitive cells, even under nonstimulating conditions. In resistant cells, neither an increase in concentration nor a variation in drug uptake can induce effects that could be compared with those observed in the sensitive line. From these results we conclude that the early effects of ADM are not modulated by drug uptake.

Cell proliferation kinetics in human solid tumors: relation to probability of metastatic dissemination and long-term survival

A large number of studies have investigated the relationship between the long-term survival and the percentage of tumor cells in S phase assessed by autoradiography after tritiated thymidine labelling, image cytometry, flow cytometry or labelling with an halogenated analog of thymidine, in various types of human solid tumors. The survey of the results clearly shows that the S-phase fraction (SPF) is of high prognostic significance in several types of cancers, in particular in breast cancers, non-Hodgkin lymphomas, ovarian cancers, neuroblastoma, bladder cancers and lung cancers. SPF was found of high independent significance in 10 of the 11 studies in which multivariate analyses of prognostic factors had been carried out. Proliferation appears generally to be of higher prognostic significance than ploidy. In view of the wide differences in the biological characteristics of the tumors studied, it is likely that the association between a high proliferation rate and the degree of tumor aggressiveness is a general feature of human solid tumors. However, high proliferative rate of tumor cells is probably not the cause of tumor biological aggressiveness but a variable associated with it. The extent to which cells escape from the regulatory systems which control their proliferation appears to be a good index of tumor progression.

Comparative study of proportion of S-phase cells in ascites and pleural effusions in ovarian carcinoma using antibromodeoxyuridine monoclonal antibody and DNA flow-cytometry

Bromodeoxyuridine (Brd-Urd) was utilized in vitro to detect proliferating cells in 33 samples of ascitic and pleural effusions of ovarian malignancies and the results were compared with DNA flow-cytometry. Percoll separated tumor cells were incubated in vitro with Brd-Urd. After treatment with anti-Brd-Urd monoclonal antibodies the proportion of fluorescent cells was evaluated on slides by microscopy. A good correspondence (r = 0.93) was found between the proportion of cells labelled with Brd-Urd and the S-phase cells evaluated from the DNA histograms. S-phase values were found to be higher in tumors with aneuploid than in diploid DNA index. Poorly differentiated tumors had higher values as compared to moderately or well differentiated tumors.

DNA synthesis rate and unlabeled cells with S-phase DNA content in P388 leukemic cells in vivo studied by flow cytometry and cell sorting

DNA synthesis kinetics of P388 leukemic cells growing in ascites form in BDF1 hybrid mice were investigated during the periods of exponential growth and growth restriction. Incorporation of tritiated thymidine, and in some instances tritiated uridine, was studied by autoradiography in cells sorted from S-phase fractions during DNA flow cytometry. During exponential growth continuous labeling with tritiated thymidine indicated a growth fraction of unity, whereas the growth fraction was about 30% during growth restriction. At this growth phase the majority of cells with S phase DNA content remained unlabeled after pulse labeling with tritiated thymidine or uridine, indicating that both the "salvage" and the "de novo" DNA synthesis pathways were blocked in most S-phase cells. After pulse labeling with tritiated thymidine the DNA synthesis rate pattern was investigated by sorting of consecutive fractions of cells throughout the S phase followed by quantitative autoradiography. With exception of a reduced rate in the middle of S phase, the DNA synthesis rate increased as the cells progressed through S phase during exponential growth. In contrast, the DNA synthesis rate pattern had a relative peak in the middle of S phase during growth restriction, which is otherwise characterized by a low mean DNA synthesis rate.