Correlation between serum tumor marker levels and tumor proliferation in small cell lung cancer

Reevaluation of the Usefulness of Systematic Bone Scanning in Initial Staging and follow-up of Small Cell Lung Carcinoma, Taking into Account the Serum Levels of Neuron-Specific Enolase

The prescription of bone scans (BS) in the initial staging and follow-up of small cell lung carcinoma (SCLC) is a traditional attitude. The availability of the serum neuron-specific enolase (NSE) assay and budget limitations led us to evaluate retrospectively, in 57 patients, the consequences of a more selective attitude, namely to perform BS only in those patients with abnormal serum NSE levels. Both BS and NSE assays were performed in 47 patients referred for initial staging of SCLC; NSE levels were normal in 8 but in 2 of these cases (25%) secondary bone localizations with great clinical significance were discovered at BS. During follow-up, 59 BS were performed in conjunction with NSE assays; 45 NSE levels were in the normal range whereas 17 (38%) corresponding BS were suggestive of bone metastases. In conclusion, due to the frequent occurrence of false-negative results in patients with bone metastases, serum NSE levels proved to be useless in the selection for BS of patients suffering from SCLC.

Thymidine kinase activity in serum of renal cell carcinoma patients is a useful prognostic marker

It is known that the concentration and activity of the DNA precursor enzyme thymidine kinase 1 (TK1) in serum is significantly elevated in patients with malignancies, as compared with levels in patients with benign tumours and those in healthy individuals. For the first time, the use of serum TK1 as a prognostic marker for patients with renal cell carcinoma (RCC) was examined. Serum TK1 protein (STK1p) concentration and serum TK1 activity (STK1a) were determined by a dot blot chemoluminescence assay and a radio enzyme assay, respectively. There was no correlation between STK1p and STK1a in the same sera from 27 RCC patients. Only one STK1p value as compared with 15 STK1a values was clearly above the cut-off values (2 pmol/l and 6 U/l, respectively) for healthy individuals. STK1a values did not correlate with the level of TK1 expression in tumour sections from the RCC patients, estimated by immunohistochemistry staining. However, there was a significant correlation between STK1a levels and the grade, stage and size of the RCC tumours. The discrepancy between the STK1p and the STK1a results is likely to be because of reduced ability of the TK1 antibody to recognize the STK1 in sera from RCC patients. We conclude that the activity of STK1 is a useful tool for evaluating the prognosis of patients with RCC.

Thymidylate synthase activity in leukocytes from patients with chronic myelocytic leukemia and acute lymphocytic leukemia and its inhibition by phenanthroindolizidine alkaloids pergularinine and tylophorinidine

Thymidylate synthase (TS) (EC 2.1.1.45) provides precursors for DNA biosynthesis through a de novo pathway and is a key target enzyme for cancer chemotherapy. TS levels of human leukemic leukocytes from patients with chronic myelocytic leukemia (CML) and acute lymphocytic leukemia (ALL) were observed to be highly elevated (66- and 33-fold for CML and ALL, respectively) compared to the usual low level of basal activity in normal healthy controls. In vitro inhibition studies on the human leukemic leukocyte TS with the phenanthroindolizidine alkaloids pergularinine (PGL) and tylophorinidine (TPD) (isolated from the Indian medicinal herb Pergularia pallida) were conducted for the preliminary screening tests for their antitumor activity. The leukemic leukocyte enzyme activity was potently inhibited by PGL and TPD (IC50 = 50 microM) in both types of leukemias. These alkaloids were assessed for biological evaluation for the first time as potential antileukemic agents.

Serum beta(2)-microglobulin and serum thymidine kinase are independent predictors of progression-free survival in chronic lymphocytic leukemia and immunocytoma

Chronic lymphocytic leukemia (CLL) and immunocytoma (IC) are remarkably heterogeneous with regard to their clinical course. The current staging systems can distinguish prognostic subgroups, but do not seem to predict the risk of disease progression of an individual patient with sufficient accuracy. Given the increase of treatment options for CLL and IC, additional parameters are needed to decide which patients may benefit from early or intensified treatment. It has been shown that two biochemical markers, serum beta 2-microglobulin (s-beta 2M) and serum thymidine kinase (s-TK), might identify CLL and IC patients at high risk of disease progression. Therefore, the prognostic value of these two serum parameters was compared with a panel of several established prognostic factors in a prospective clinical trial. 113 patients with CLL and 41 patients with IC (mean age +/- SD 63.9 +/- 10.7 years) were included. The following parameters were determined: histopathological diagnosis (IC vs. CLL), age, sex, performance status (Karnofsky index), B symptoms, peripheral blood lymphocyte count, platelet count, blood hemoglobin, serum lactate dehydrogenase (s-LDH), s-beta 2M, s-TK, serum creatinine, number of lymph node areas involved, prior therapy, and the time from diagnosis to inclusion in the study. Univariate analyses showed that nine parameters (Karnofsky index, peripheral blood lymphocytosis, platelet count, blood hemoglobin, lymph node areas involved, pretreatment, s-LDH, s-beta 2M, and s-TK) significantly predicted progression-free survival. In a Cox regression model, only four of these parameters provided independent prognostic information on progression-free survival: 1. s-beta 2M, 2. Karnofsky index, 3. platelet count, and 4. s-TK. The results show that s-beta 2M and s-TK independently predict progression-free survival in patients with CLL and IC, and suggest that these prognostic factors may allow an improved prediction of progression-free survival, particularly in early disease stages.

Deoxythymidine kinase in the tumour cells and serum of patients with non-Hodgkin lymphomas

The levels of deoxythymidine kinase in tumour cells (C-TK) and in serum (S-TK) were investigated and the tumour volume calculated in 89 patients with non-Hodgkin lymphoma (NHL), in order to ascertain the importance of C-TK and tumour burden as regards the S-TK levels. Among all patients, a correlation was seen between S-TK and tumour volume but not between S-TK and C-TK. However, within different tumour volume categories (small, medium-sized and large), there was a correlation between S-TK and C-TK. Multiple regression analysis supported this notion. C-TK correlated with the proliferation-associated parameters, S-phase fraction and mitotic index. As already known, S-TK was found to have a strong prognostic value. C-TK and tumour burden were also of prognostic value. In multivariate analyses, C-TK and tumour volume did not provide prognostic information in addition to S-TK, whereas, in the absence of S-TK, C-TK and tumour volume did provide additional information. It is concluded that the serum level of TK depends on both the tumour burden and the tumour cell proliferation rate. Based upon estimations of S-TK in patients assessed shortly after chemotherapy, we also suggest that S-TK reflects the number of proliferating cells that have died during the period immediately before sampling.

Thymidine kinase: a tumor marker with prognostic value for non-Hodgkin's lymphoma and a broad range of potential clinical applications

Thymidine kinase (TK) is a cellular enzyme which is involved in a "salvage pathway" of DNA synthesis. It is activated in the G1/S phase of the cell cycle, and its activity has been shown to correlate with the proliferative activity of tumor cells. Additionally, certain viruses are able to induce cellular TK production and activity. Clinical studies have reported elevated serum TK levels in a variety of neoplasias. The majority of these studies concerned hematologic malignancies. TK seems to be a useful marker in non-Hodgkin's lymphoma, where it correlates with clinical staging and provides significant prognostic information on (progression-free) survival. Preliminary results in acute myeloid leukemia indicate that pretreatment serum TK values may predict the response to the first induction chemotherapy. Moreover, serum TK appears to have some clinical value in such solid tumors as prostate cancer, breast cancer, and small-cell lung cancer, whereas it is not a reliable marker of non-small-cell lung cancer and brain tumors.

No correlation between tumor markers and prognosis under polygenic control systems

Tumor markers in serum should not be correlated with the prognosis of patients with malignant tumors, although the markers indicate the presence of tumors, since marker levels and prognosis are controlled independently by poly-genes. Furthermore, prognostic factors, including incidence of pulmonary metastasis, tumor growth rate, tumor drug sensitivity and host response, vary among patients. In general, tumor markers may be used to demonstrate response of tumor to treatments only when expression of the markers does not change in a time-dependent manner.