Effects of the conventional antitumor therapies surgery, chemotherapy, radiotherapy and immunotherapy on regulatory T lymphocytes in cancer patients.

BACKGROUND: Several clinical studies have clearly demonstrated that the immune status is one a major prognostic factor for the survival time in cancer patients. However the main clinical problem is to identify the most prognostically important index within the great number of immune parameters. Recently the evaluation of regulatory T (T-reg) (CD4CD25) lymphocyte count and function with respect to the T helper (TH) (CD4) number has been shown to represent the main immune parameters capable of representing the functional status of the anticancer immunity in cancer patients. This study evaluated the influence of the four main conventional anticancer therapies (surgery, chemotherapy, radiotherapy, immunotherapy) on the CD4/CD4CD25 ratio. PATIENTS AND METHODS: The study included 70 patients. The oncological treatments consisted of surgery in 14, chemotherapy in 36, radiotherapy in 12 and immunotherapy (subcutaneous low-dose, S.C.-low, interleukin, IL-2) in 8 patients. The normal value of the CD4/CD4CD25 ratio was greater then 4.0. RESULTS: Surgery induced a significant decline in the CD4/CD4CD25 mean ratio. Radiotherapy also induced also a dramatic significant decrease in the CD4/CD4CD25 ratio, whereas the effect of both chemotherapy and immunotherapy reflected the clinical response to the treatments. The CD4/CD4CD25 mean ratio was significantly enhanced in the patients who obtained control of the neoplastic growth, whereas it diminished in progressing patients. CONCLUSION: The commonly used anticancer therapies profoundly modify the levels of amounts of T-reg lymphocytes. Because of the fundamental role of T-reg cells in suppressing the anticancer immunity, thus diminishing survival, the monitoring of the CD4/CD4CD25 ratio could constitute an important clinical index during conventional anticancer therapies to predict the prognosis of cancer patients.

Progress report on the palliative therapy of 100 patients with neoplastic effusions by intracavitary low-dose interleukin-2.

OBJECTIVE: Several cytokines, particularly IL-2 and interferons, are thought to be effective in the palliative therapy of neoplastic effusions. We report on the activity and toxicity of intracavitary administration of low-dose IL-2 in a case series of 100 cancer patients with neoplastic effusions. METHODS: One hundred patients with advanced solid tumors and neoplastic effusions underwent IL-2 intracavitary injection as first-line treatment. The most common sites of fluid accumulation were pleura (n = 68), peritoneum (n = 21) and pericardium (n = 11). Breast cancer, lung cancer and mesothelioma were the most frequent neoplasms in our series. One cycle consisted of intracavitary IL-2 at 6,000,000 IU on days 1 and 7. RESULTS: According to Paladine's criteria, an objective clinical response was achieved in 72% (complete response in 27% and partial response in 45%), with a median duration of 5 months (range: 1-11 months). The peritoneum was the least responsive site for neoplastic effusion reduction. IL-2 intracavitary injection was well tolerated in all patients; the only toxicity observed was fever >38 degrees C in 6% of the patients. CONCLUSION: This study shows that intracavitary injection of IL-2 represents a feasible, well-tolerated and effective therapy of neoplastic fluid accumulation. Further studies are needed in order to compare the effectiveness of intracavitary IL-2 with other standard treatments.

Acute pneumocephalus: an unusual complication of thoracotomy.

The authors describe a iatrogenic cerebrospinal fluid fistula into the pleural cavity, a rare and unusual complication of thoracic surgery. The importance of considering this diagnosis in patients who suffer from headache and altered mental status after thoracotomy and the early surgical repair of this potentially fatal complication are stressed.

Relation between macrophage and T helper-2 lymphocyte functions in human neoplasms: neopterin, interleukin-10 and interleukin-6 blood levels in early or advanced solid tumors.

At present, it is known that there are two main mechanisms responsible for cancer-related immunosuppression, mediated by macrophages and by TH2 lymphocytes. The relation existing between macrophage- and TH2-mediated immunosuppression still remains to be understood. The present study was performed in an attempt to establish which is the correlation existing in cancer patients between IL-10 and neopterin levels, which reflect TH2- and macrophage-mediated suppressive events, respectively. The study included 40 solid tumor patients and 60 healthy subjects as controls. Serum concentrations of neopterin and IL-10 were measured by the RIA method and by an immuno-enzymetric assay, respectively. Because of its possible production both by TH2 and macrophages, serum levels of IL-6 were also determined. Neopterin, IL-10 IL-6 mean concentrations were significantly higher in cancer patients than in controls. Mean values of both neopterin and IL-6 were significantly higher in metastatic patients than in those with locally limited disease. IL-10 mean levels were also significantly higher in patients with metastatic disease. IL-6 levels were significantly correlated with those of neopterin, whereas no correlation was found between neopterin and IL-10 values. This preliminary study would suggest that macrophage- and TH2-mediated immunosuppression may occur independently in solid tumors, and that it becomes more evident with disease progression.

Intracavitary therapy of neoplastic effusions with cytokines: comparison among interferon alpha, beta and interleukin-2.

Preliminary studies have suggested that the intracavitary administration of cytokines may represent a new effective palliative therapy of malignant effusions. To define further the therapeutic role of cytokines in the treatment of neoplastic fluid accumulation, 70 cancer patients with pleural, pericardial or peritoneal cytologically proven neoplastic effusions were randomized to receive intracavitary cycles with interleukin-2 (IL-2; 6 x 10(6) IU), interferon (IFN alpha; 2 x 10(7) U) or IFN beta (6 x 10(6) U) every week for 2 or 3 weeks. A clinical control of fluid accumulation was obtained in 39/70 (56%) patients. In patients with mesothelioma, the response rate was significantly higher with IL-2 than with IFN alpha or -beta, while there was no difference in patients with tumors other than mesothelioma. Moreover, the duration of the period during which drainage was not required was significantly longer in patients treated with Il-2 than in the other groups. Toxicity was low in all patients. According to preliminary data, this study demonstrates that intracavitary administration of cytokines, including IL-2, IFN alpha and -beta, is a new well-tolerated palliative therapy for malignant effusions, with an efficacy substantially comparable to that described with the most commonly used treatments with tetracyclines or cytostatic agents.

Efficacy and tolerability of cancer neuroimmunotherapy with subcutaneous low-dose interleukin-2 and the pineal hormone melatonin - a progress report of 200 patients with advanced solid neoplasms.

The recent advances in psychoneuroimmunology have demonstrated the existence of a psychoneuroendocrine control of the antitumor immunity. Our previous preliminary studies indicated the possibility of amplifying the biological and therapeutic efficacy of IL-2 cancer immunotherapy by immunomodulating neurohormones, mainly the pineal indole melatonin (MLT), in most advanced solid tumors, including those which generally do not respond to IL-2 alone. This study reports on the results obtained by low-dose IL-2 plus MLT in 200 patients with advanced solid neoplasms, for whom no other effective standard therapy was available. Non-small cell lung cancer, pancreatic adenocarcinoma, hepatocarcinoma, colon cancer and gastric cancer were the neoplasms most frequently detected in our patients. In addition, all patients had a life expectancy less than 6 months. IL-2 was given subcutaneously at 3 million IU/day for 6 days/week for 4 weeks; MLT was given orally at 40 mg/day. In non-progressing patients, a second cycle was given after a 21-day rest period; then, patients underwent a maintenance period consisting of one week of therapy every month until progression. A complete response (CR) was achieved in 4 patients (hepatocarcinoma 2; pancreas 1; gastric cancer 1), a partial reasponse (PR) was achieved in 36 patients (lung 12; liver 6; stomach 4; pancreas 3; colon 3; breast 2; miscellaneous 6). Tumor response rate (CR+PR) was 40/200 (20%) patients. Longer than one year survival was achieved in 79 (39%) patients. Toxicity was mild in all patients, and therapy was administered as a home therapy. The present study confirms in a great number of patients the possibility to induce objective tumor regressions in most advanced solid tumor histotypes by low-dose IL-2 plus MLT. Thus, immunotherapy with IL-2 and MLT may be considered as a new well tolerated and effective therapy of almost all advanced solid tumors, including those which do not respond to IL-2 alone or to chemotherapy.

Role of the pineal gland in the control of macrophage functions and its possible implication in cancer: a study of interactions between tumor necrosis factor-alpha and the pineal hormone melatonin.

Recent studies have shown the existence of reciprocal links between cytokine activity and immunomodulating neurohormones or neuropeptides. In particular, the pineal hormone melatonin (MLT) appears to influence IL-2 activity in cancer. The present study was performed to evaluate which interaction exists between MLT and another important cytokine, tumor necrosis factor-alpha (TNF), which is responsible for both antitumor cytolytic activity and cancer-related cachexia. In a first study, we analyzed MLT circadian rhythm under TNF administration (0.75 mg/day i.v. for 5 days) in 10 metastatic solid tumor patients. In a second study, we evaluated TNF serum levels in 10 metastatic solid tumor patients under therapy with MLT alone (20 mg/day orally in the evening for at least 1 month). In a third study, we have measured concomitantly daily serum levels of MLT and TNF in 30 patients with metastatic solid neoplasms. Nocturnal mean serum concentrations significantly increased in response to TNF injection. MLT therapy induced a significant decline in TNF mean values. Finally, patients with abnormally high MLT diurnal levels showed significantly lower TNF mean concentrations with respect to those with normal levels of the pineal hormone. This study, by showing the stimulatory effect of TNF on MLT secretion and the inhibitory action of MLT on TNF release, would suggest the existence of feed-back mechanisms operating between the pineal gland and TNF released from macrophages in human neoplasms.

A randomised study with subcutaneous low-dose interleukin 2 alone vs interleukin 2 plus the pineal neurohormone melatonin in advanced solid neoplasms other than renal cancer and melanoma.

Our previous experimental studies have shown that the best approach to increase the biological anti-tumour activity of interleukin 2 (IL-2) is not co-administration of another cytokine, but the association with immunomodulating neurohormones, in an attempt to reproduce the physiological links between psychoendocrine and immune systems, which play a fundamental role in the regulation of the immune responses. In particular, the association with the pineal neurohormone melatonin (MLT) has been shown to cause tumour regressions in neoplasms that are generally non-responsive to IL-2 alone. To confirm these preliminary results, a clinical trial was performed in locally advanced or metastatic patients with solid tumours other than renal cell cancer and melanoma. The study included 80 consecutive patients, who were randomised to be treated with IL-2 alone subcutaneously (3 million IU day-1 at 8.00 p.m. 6 days a week for 4 weeks) or IL-2 plus MLT (40 mg day-1 orally at 8.00 p.m. every day starting 7 days before IL-2). A complete response was obtained in 3/41 patients treated with IL-2 plus MLT and in none of the patients receiving IL-2 alone. A partial response was achieved in 8/41 patients treated with IL-2 plus MLT and in only 1/39 patients treated with IL-2 alone. Tumour objective regression rate was significantly higher in patients treated with IL-2 and MLT than in those receiving IL-2 alone (11/41 vs 1/39, P < 0.001). The survival at 1 year was significantly higher in patients treated with IL-2 and MLT than in the IL-2 group (19/41 vs 6/39, P < 0.05). Finally, the mean increase in lymphocyte and eosinophil number was significantly higher in the IL-2 plus MLT group than in patients treated with IL-2 alone; on the contrary, the mean increase in the specific marker of macrophage activation neopterin was significantly higher in patients treated with IL-2 alone. The treatment was well tolerated in both groups of patients. This study shows that the concomitant administration of the pineal hormone MLT may increase the efficacy of low-dose IL-2 subcutaneous therapy.

Cancer immunotherapy with low-dose interleukin-2 subcutaneous administration: potential efficacy in most solid tumor histotypes by a concomitant treatment with the pineal hormone melatonin.

The antitumor efficacy of IL-2 is limited to renal cancer and melanoma. Several cytokines have been associated with IL-2 in an attempt to improve its activity, without, however, any clear benefit. Recent experimental and clinical studies have suggested the possibility to manipulate the host biological response by immunomodulating neurohormones, such as the pineal hormone melatonin (MLT). On the bases of these considerations, we have designed a neuroimmunotherapeutic protocol with low-dose IL-2 subcutaneous therapy (3 million IU/day for 6 days/week for 4 weeks) plus MLT (40 mg/day orally, starting 7 days before IL-2) in advanced solid neoplasms other than renal cancer and melanoma, which are generally resistant to IL-2 alone. The study included 82 patients, 72 of whom showed distant organ metastases. Tumor histotypes were, as follows: non-small cell lung cancer: 19; hepatocarcinoma: 16; colon cancer: 15; gastric cancer: 11; cancer of pancreas: 11; breast cancer: 6; miscellaneous: 4. Objective tumor regression were achieved in 17/82 (21%) patients, consisting of CR in 4 (liver: 2; pancreas: 1; stomach: 1) and PR in 13 (lung: 4; liver: 4; stomach: 2; pancreas: 1; breast: 1; colon: 1). The median duration of response was 8+ months. A stabilization of disease was obtained in 30 patients, while the other 35 patients progressed. The lack of progression was associated with a significantly higher increase in lymphocyte and eosinophil mean number and with a significantly lower increase in neopterin mean levels. The treatment was well tolerated in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro modulatory effects of interleukin-3 on macrophage activation induced by interleukin-2.

BACKGROUND: The concomitant activation of macrophage-mediated immunosuppressive events might represent one of the most important biologic factors responsible for the decreased efficacy of cancer immunotherapies, including that of interleukin (IL)-2. In previous studies, the authors observed that the increase in the soluble IL-2 receptor (SIL-2R) and neopterin levels was related to the generation of macrophage-mediated immunosuppression and associated with a reduced clinical efficacy during IL-2 cancer immunotherapy. Because both cytokines and neurohormones may influence the macrophage system, the current study was done to evaluate the effects of IL-3 and of the pineal hormone melatonin (MLT) on monocyte response to IL-2 administration. METHODS: Peripheral blood monocytes were incubated with different concentrations of IL-2, IL-3, and MLT, either alone or in association. RESULTS: SIL-2R, neopterin, and tumor necrosis factor-alpha mean concentrations in the medium significantly increased during incubation with IL-2 at a concentration of 100 Cetus units/ml. IL-3 alone, at a dose of 10 ng/ml, also stimulated tumor necrosis factor release; no effect was found on SIL-2R and neopterin. The IL-2-induced neopterin rise was blocked by a concomitant incubation with IL-3 at a dose of 10 ng/ml. Finally, the concomitant incubation with IL-3 and MLT further inhibited neopterin release and significantly decreased IL-2-induced SIL-2R secretion. CONCLUSIONS: These results suggest that IL-3 alone or in association with MLT may modulate macrophage functions during cancer immunotherapy with IL-2 and decrease the IL-2-induced macrophage activation.

In vivo biological results of the association between interleukin-2 and interleukin-3 in the immunotherapy of cancer.

The concomitant generation of macrophage-mediated suppressive events, as documented by the increase in neopterin and soluble interleukin-2 (IL-2) receptor (SIL-2R), and the enhanced production of cortisol, would represent the most investigated phenomena responsible for the reduced anticancer efficacy of IL-2 immunotherapy in humans. Based on our preliminary experimental studies suggesting a modulatory role of IL-3 on immune and endocrine effects induced by IL-2, a study was performed to evaluate the influence of IL-3 on biological effects of IL-2 cancer immunotherapy. We have evaluated 12 immunotherapeutic courses with IL-3 plus IL-2, which were performed in 6 patients with metastatic non-small cell lung cancer. The results were compared to those seen in 22 courses with IL-2 alone, carried out in 12 patients with metastatic non-small cell lung cancer. IL-3 was given intravenously at a daily dose of 1 microgram/kg/b.w. at 6 p.m. for 14 consecutive days, starting 7 days before IL-2. IL-2 was given subcutaneously at a dose of 3 million IU twice/daily for 5 days/week for 3 weeks. The increase in serum levels of the specific macrophage marker neopterin, induced by IL-2, was completely blocked by IL-3. The IL-2-induced SIL-2R rise was significantly lower during IL-3 plus IL-2 than under IL-2 alone. The increase in cortisol levels in response to IL-2 was neutralised by IL-3. The increase in lymphocyte, T lymphocyte, natural killer (NK) cell, activated T lymphocyte and eosinophil mean number was significantly higher during IL-3 plus IL-2 than during IL-2 alone. Episodes of fever, asthenia, anorexia, vomiting, anaemia and thrombocytopenia were significantly more frequent in patients receiving IL-2 alone than in those treated with IL-3 and IL-2. This preliminary study would suggest that IL-3 may improve the tolerability of IL-2 immunotherapy and enhance the biological antitumour properties of IL-2 by neutralising cortisol increase and macrophage-mediated suppressive events, with a following potential amplification of Il-2 anticancer efficacy.

Amplification of eosinophilia by melatonin during the immunotherapy of cancer with interleukin-2.

Eosinophilia, which occurs during IL-2 immunotherapy, has appeared to be due to an enhanced secretion of IL-5 and to be associated with a clinical response. Since our previous experimental studies showed that the pineal hormone MLT potentiates IL-2 efficacy, a study was started to evaluate the influence of a concomitant MLT administration on IL-2-induced eosinophilia. The study included 30 advanced solid tumor patients, 16 of whom received IL-2 alone (6 million IU/day) and the other 14 IL-2 plus MLT (10 mg/day orally at 8.00 P.M.). Eosinophil mean number was significantly enhanced during both treatments, but its increase in patients receiving IL-2 plus MLT was significantly higher than that seen in patients treated with IL-2 alone. These results show that MLT may enhance IL-2-induced eosinophilia, by suggesting that T helper lymphocyte- type 2, which is the source of IL-5, may be the target cell for MLT action.

Modulation of macrophage response to interleukin-2 immunotherapy by interleukin-3 in cancer patients.

It has been observed that neopterin, a specific marker of macrophage activation, increases during cancer immunotherapy with IL-2, and this effect is mediated by interferons produced by IL-2-stimulated lymphocytes. Moreover, our previous studies have shown that neopterin rise during IL-2 immunotherapy is associated with an enhanced release of soluble IL-2 receptor (SIL-2R), which may suppress IL-2-dependent immune functions. This finding would suggest that neopterin increase may be related to the generation of suppressive events, which occur during IL-2 immunotherapy. On the basis of the documented modulatory effect of IL-3 on macrophage functions, we have evaluated the influence of IL-3 on neopterin secretion during IL-2 immunotherapy. The study was performed in advanced lung cancer patients. We have investigated 9 immunotherapeutic courses consisting of IL-2 (6M IU/day s.c. for 5 days/week for 3 weeks) plus IL-3 (1 microgram/(kg x day) i.v. for 14 days, starting 7 days before IL-2). The results were compared to those found during 18 courses with IL-2 alone. Mean neopterin levels increased significantly during IL-2 alone, but not in response to IL-3 plus IL-2. SIL-2R rise was significantly higher during IL-2 than during IL-3 plus IL-2. Mean numbers of NK cells and activated lymphocytes increased significantly in both groups of patients, but were significantly lower at the end of the treatment in patients receiving IL-2 alone than in those treated with IL-3 plus IL-2.(ABSTRACT TRUNCATED AT 250 WORDS)

Endocrine effects of human recombinant interleukin-3 in cancer patients.

It is known that several cytokines can exert hormonal effects. At present, no data are available about the possible influence of IL-3 on the endocrine system. In order to investigate the endocrine effects of IL-3 in humans, we have evaluated serum levels of cortisol, beta-endorphin, GH, PRL, FSH, LH, TSH and melatonin in response to intravenous injection of IL-3 at a dose of 1 mcg/kg b.w. at 6.00 p.m. The study was performed in 5 non-small cell lung cancer patients. GH increased significantly in response to IL-3. PRL showed a progressive decrease after IL-3 injection, but its variations were not statistically significant. All other hormones, including cortisol, were not affected by IL-3. This preliminary study shows that IL-3 may exert endocrine effects in humans, which would seem at variance with previously reported results on most other cytokines.

Inhibitory effect of interleukin-3 on interleukin-2-induced cortisol release in the immunotherapy of cancer.

The stimulatory effect of IL-2 on cortisol rise represents an undesirable biological event during IL-2 cancer immunotherapy. At present, no cytokine has been proven to be able to counteract IL-2-induced cortisol increase. This study was carried out to evaluate the influence of IL-3 on IL-2 stimulation of cortisol secretion. Five lung cancer patients were investigated after IL-2 (3 x 10(6) IU s.c.), after IL-3 (1 mcg/kg b.w. i.v.) and after IL-3 plus IL-2, by administering IL-3 two hours before IL-2 injection. IL-2 significantly stimulated cortisol secretion. IL-3 alone had no effect on cortisol levels. The pretreatment with IL-3 completely neutralizes IL-2-induced cortisol release. These preliminary results would suggest that IL-3 may be associated with IL-2 during cancer immunotherapy to modulate the effect of IL-2 on the endocrine system.

Tumor necrosis factor in solid tumors: increased blood levels in the metastatic disease.

TNF, a cytokine produced by macrophages, is able either to exert an antitumor activity, or to determine severe clinical complications, such as cachexia and septic shock. Increased blood levels of TNF have been described in cancer patients. The present study was performed to better define TNF secretion in patients with solid tumors. The study included 48 cancer patients (lung cancer: 22; colon cancer: 11; breast cancer: 10; renal cancer: 5), and among them 27 showed distant organ metastases. TNF serum levels were measured by IRMA method. The control group comprised 40 healthy subjects. TNF levels were also evaluated in relation to those of SIL-2R, whose increase seems to be associated with an unfavorable prognosis in cancer. High levels of TNF were seen in 27/48 (56%) patients. Mean levels of TNF were significantly higher in cancer patients than in controls. Moreover, within the cancer group, TNF mean values were significantly higher in metastatic patients than in those without metastases; the highest levels were observed in patients with visceral lesions as dominant metastasis sites. Finally, patients with high TNF concentrations showed significantly higher mean levels of SIL-2R than those with normal values. This study shows that the neoplastic metastatic disease is associated with an exaggerated TNF secretion.

Biological and clinical results of a neuroimmunotherapy with interleukin-2 and the pineal hormone melatonin as a first line treatment in advanced non-small cell lung cancer.

The metastatic non-small cell lung cancer (NSCLC) still remains an untreatable disease, and the role played by chemotherapy has yet to be defined. The new immunotherapeutic strategies, such as interferon and IL-2, seem to be also less effective, since they generally determine only a stabilisation of disease. On the basis of previous experimental results suggesting a synergistic action between IL-2 and the pineal neurohormone melatonin (MLT), a study was started to evaluate the clinical efficacy and toxicity of a neuroimmunotherapeutic combination consisting of IL-2 plus MLT as a first line therapy in metastatic NSCLC. The study included 20 patients (adenocarcinoma: 10; epidermoid cell carcinoma: 7; large cell carcinoma: 3). MLT was given orally at a dose of 10 mg day-1 at 8.00 pm every day, starting 7 days before the onset of IL-2 administration. IL-2 was given subcutaneously at a dose of 3 x 10(6) IU m-2 every 12 h for 5 days/week for 4 weeks, corresponding to one cycle of immunotherapy. In responder patients or in those with stable disease, a second cycle was given after a rest-period of 21 days. A partial response was achieved in 4/20 (20%) patients. Ten other patients had a stable disease (50%), whereas the last six patients progressed. Toxicity was low in all cases. This study shows that the neuroimmunotherapeutic therapy with IL-2 and the pineal hormone MLT may represent a new effective and well tolerated treatment in metastatic NSCLC, with results comparable to those obtained with chemotherapy, but with an apparent lower biological toxicity.

Postoperative increase in soluble interleukin-2 receptor serum levels as predictor for early recurrence in non-small cell lung carcinoma.

It is known that interleukin-2 (IL-2) plays an important role in the activation of host antitumor immune response. In addition to IL-2 cell surface receptor, a soluble form of IL-2 receptor (SIL-2R) may be released in the blood and potentially be involved in the regulation of IL-2 availability. High SIL-2R levels have been found in patients with lung cancer. The current study evaluated the influence of changes in SIL-2R serum levels during the perioperative period on early relapse rate in patients with operable non-small cell lung cancer. The study included 60 patients (epidermoid carcinoma, 33; adenocarcinoma, 27). Serum levels of SIL-2R were measured with an enzyme immunoassay before surgery and 7 and 30 days after surgery. A surgery-induced increase in SIL-2R levels was seen 7 days after surgery in 38 of 60 patients. On the 30th day after surgery, SIL-2R values were lower than the preoperative values in 32 patients (Group A) or still greater in the other 28 patients (Group B). After a median follow-up of 10 months, relapse occurred in 19 of 60 patients. The relapse rate was significantly higher in Group B than in Group A patients (16 of 28 versus 3 of 32, respectively; P less than 0.001). This difference also was significant in relation to histotype and node status. This study shows that the persistence of increased SIL-2R levels in the postoperative period is associated with a higher early relapse rate in patients with operable non-small cell lung cancer. The impact of SIL-2R levels on relapse suggests that host immune defenses may influence the clinical course of patients with lung cancer. Therefore, the evaluation of SIL-2R in the perioperative period may represent a new prognostic biologic factor in operable non-small cell lung cancer.