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High free tryptophan (F-TRP) plasma levels are found in cancer patients (CP). F-TRP plasma concentrations are affected by the levels of its carrier, albumin (ALB), and free fatty acids (FFA) competing with TRP for ALB binding sites. The lack of correlation between F-TRP, ALB and FFA in CP suggests a tumor-dependent effect on the rise in F-TRP. To verify this hypothesis, F-TRP, ALB and FFA levels were assayed in 12 lung and 16 breast CP susceptible to radical surgery, before and 15 days after surgical removal of the tumor. F-TRP levels significantly decreased after tumor ablation. Since no correlation was found between F-TRP, ALB and FFA variations, it is conceivable that the tumor itself may be responsible for the high F-TRP levels in CP.

The chemosensitivity of 26 non-pretreated colorectal carcinomas (primary tumors and/or colorectal metastases) was studied by an in vitro antimetabolic assay, which evaluates the interference of drugs on the incorporation of 3H-thymidine and 3H-uridine in short-term cultures of human tumors. Our results correlate with the response rate obtained in clinical studies with monochemotherapy and justify the possibility of a future prospective study using individually tailored chemotherapy regimens. Doxorubicin-analogues, with an overall in vitro efficacy in 16.0 % and 14.3 % for 4-epidoxorubicin (epi-DX) and 4-deoxydoxorubicin (deo-DX), respectively, seem to deserve a modest role in the treatment of colorectal cancer, provided that a careful selection of patients is performed. Variability in anthracycline activity is indeed evident, also in our study, in relation to the different neoplastic picture of the various patients.

One major problem in primary breast cancer is the identification of new parameters able to select patients at high risk of recurrence. Our study was aimed at detecting mammary tumor cells in the bone marrow of breast cancer patients using a single bone marrow sampling and the monoclonal antibody AB/3. This antibody recognizes a membrane carbohydrate epitope present in human breast cancer cells but not in normal tissues. Only 2 out of 45 breast cancer patients were found to have a bone marrow positive AB/3 staining reaction. Our data confirm and extend previous reports that single bone marrow sampling coupled with immunocytochemistry is not sensitive enough to be used as a routine procedure to acquire prognostic information in breast cancer.

Abnormalities in lipid metabolism have been widely described in cancer-bearing patients and animals. In particular, the presence of the tumor seems to profoundly affect triglyceride (TG) utilization by interfering with lipoprotein lipase (LPL) activity. Exogenous TG plasma clearance was evaluated in 10 nonmalnourished patients with cancers of various origin and 10 normolipidemic volunteers by means of a three-stage intravenous lipid clearance test. This technique allows precise determination of both the fractional removal rate (K2) and the maximal clearing capacity (K1) for exogenous lipids. Mean K2 values (min-1) were found to be significantly reduced in cancer patients compared with control subjects (0.07 +/- 0.006 vs 0.13 +/- 0.013 SEM, p less than 0.005). K1 values (mumol/L/min) were also found to be significantly lower in cancer patients than in the control group (109.43 +/- 6.3 vs 143 +/- 6.3 SEM, p less than 0.01). The data obtained indicate that the capacity to eliminate exogenous lipids from the bloodstream is reduced in cancer-bearing patients. This may be the consequence of a tumor-related impairment of LPL system activity.