Jun-ichi Yamashita

Detection of circulating tumor cells in patients with non–small cell lung cancer undergoing lobectomy by video-assisted thoracic surgery: A potential hazard for intraoperative hematogenous tumor cell dissemination

OBJECTIVE We prospectively tested whether circulating tumor cells can be found in the preoperative, intraoperative, and postoperative peripheral blood of patients with resectable non-small cell lung cancer who undergo video-assisted lobectomy. METHODS We assayed for carcinoembryonic antigen messenger RNA (mRNA) by reverse transcriptase-polymerase chain reaction in the peripheral blood taken before, during, just after the completion of the lobectomy and then 2 to 3 weeks, and again 5 to 6 weeks, after the operation in 29 patients with pathologic stage I non-small cell lung cancer who underwent video-assisted lobectomy. We also analyzed the prognostic value of carcinoembryonic antigen mRNA expression pattern in an additional 57 patients with stage I non-small cell lung cancer, whose blood samples were previously assayed for carcinoembryonic antigen mRNA. RESULTS Of the 29 patients, the preoperative blood samples from 18 patients were negative for carcinoembryonic antigen mRNA. Of these 18 patients, 16 (89%) had positive test results during operation, although the remaining 2 patients (11%) consistently showed negative test results. The occurrence of this change from negative to positive tests results for carcinoembryonic antigen mRNA during video-assisted lobectomy was significantly higher than in patients who underwent open lobectomy in a previous study (18 of 35 patients; 51%; P <.001). In the 57 patients with stage I cancer whose blood samples were previously assayed for carcinoembryonic antigen mRNA, patients with persistently positive test results for carcinoembryonic antigen mRNA before and during operation had a significantly shorter survival when compared with those patients whose test results were persistently positive. CONCLUSIONS Video-assisted lobectomy, as compared with open lobectomy, for non-small cell lung cancer may increase the risk of seeding tumor cells into the circulation during operation.

Overexpression of group II phospholipase A2 in human breast cancer tissues is closely associated with their malignant potency

Membrane-associated phospholipase A2 (M-PLA2) is an enzyme that hydrolyses the sn-2 fatty acyl ester bond of phosphoglycerides. We measured M-PLA2 concentration in tissue extracts from 325 human breast cancers using a specific radioimmunoassay recently developed. Correlation analyses between the tissue concentration of M-PLA2 and clinicopathological factors showed that the enzyme level was significantly higher in patients with distant metastasis than in those without. In addition, M-PLA2 concentration was significantly higher in scirrhous carcinoma than in other histological types. No significant association was found between M-PLA2 concentration and age, menstrual status, tumour size, histological grade, vessel involvement or oestrogen receptor (ER) and progesterone receptor (PR) status. The expression of M-PLA2 mRNA was examined in a fibroadenoma, a stage IV breast cancer and its metastatic site of skin. Northern blot analysis showed a clear hybridisation band corresponding to M-PLA2 mRNA in both primary breast cancer and its metastatic site, while the fibroadenoma expressed a faint band corresponding to M-PLA2 mRNA. Breast cancer patients with high M-PLA2 concentrations exhibited significantly shorter disease-free and overall survival than those with low M-PLA2 concentration at the cut-off point of 5 ng 100 mg-1 protein, which was determined in a separate study. In multivariate analysis, M-PLA2 was found to be an independent prognostic factor for disease recurrence and death in human breast cancer. The possible significance of M-PLA2 expression in human breast cancer tissue is discussed.

Increased expression of membrane-associated phospholipase A2 shows malignant potential of human breast cancer cells

Background. Recently, the authors reported that membrane‐associated phospholipase A2 (M‐PLA2) was one of the acute phase reactants and increased in serum of patients with various malignant tumors.

Detection of circulating tumor cells by reverse transcriptase-polymerase chain reaction in patients with resectable non-small-cell lung cancer.

OBJECTIVE We tested whether circulating tumor cells can be detected in the peripheral blood of patients with resectable non-small-cell lung cancer (NSCLC) by reverse transcriptase-polymerase chain reaction (RT-PCR) of carcinoembryonic antigen (CEA) mRNA. METHODS We assayed for CEA mRNA by RT-PCR in the peripheral blood, taken at the time of diagnosis before surgical intervention and again 2 to 3 weeks postoperatively, from 103 patients with NSCLC who underwent curative lobectomy. Blood samples taken from 15 patients with interstitial pulmonary fibrosis who underwent an open-lung biopsy and from 32 healthy subjects served as controls. RESULTS No control samples were positive for CEA by RT-PCR. Sixty-two (60%) of the preoperative blood samples from the 103 patients with NSCLC were positive. Of these 62 samples, 27 (44%) remained positive even after surgical intervention, whereas the remaining 35 samples (56%) became negative. The incidence of positive CEA mRNA correlated highly with pathologic TNM stage of disease in both the preoperative and postoperative blood samples. CONCLUSIONS Many patients with resectable NSCLC have detectable levels of circulating cells expressing carcinoembryonic antigen even after surgical intervention. Such patients may have a higher rate of relapse.

Elevation of serum group II phospholipase A2 levels in patients with advanced cancer

To investigate the role of group II phospholipase A2 (M-PLA2) in cancer, we examined M-PLA2 serum levels in 170 pre-operative patients with various cancers and found elevated levels in 49% of them. M-PLA2 serum levels were significantly higher in patients with tumor stages T2-4, N1, M1 and stages II to IV than in T1, N0, M0 and stage I tumors, respectively. In all nine post-operative patients tested, M-PLA2 decreased 14 days after tumor resection and reduced to normal levels in 4 patients. Six of 16 carcinoma cell lines (37.5%) spontaneously secreted M-PLA2 into the culture supernatant despite the absence of IL-6 and IL-1 in 5 of the 6 lines. These results demonstrate that M-PLA2 produced by cancer cells may contribute, at least in part, to the elevation of serum M-PLA2 levels observed in cancer patients.

Production of immunoreactive polymorphonuclear leucocyte elastase in human breast cancer cells: possible role of polymorphonuclear leucocyte elastase in the progression of human breast cancer

Breast cancer cells are known to express various proteolytic enzymes, which make them invasive and favour their dissemination to distant sites. However, it is unclear whether breast cancer cells have the ability to produce polymorphonuclear leucocyte elastase (PMN-E). We measured immunoreactive (ir) PMN-E content in the conditioned medium of two breast cancer cell lines, MCF-7 and ZR-75-1, and two normal breast epithelial cell lines, HBL-100 and Hs 578Bst, using a highly specific and sensitive enzyme immunoassay. Furthermore, ir-PMN-E content was determined in tissue extracts from 62 human breast cancers. ir-PMN-E content in the culture medium of MCF-7 cells and ZR-75-1 cells increased as a function of time, regardless of the presence or absence of oestradiol. On the other hand, no detectable ir-PMN-E was secreted into the culture medium of HBL-100 and Hs 578Bst cells. ir-PMN-E was detectable in 59 of 62 tissue extracts prepared from human breast cancers, the concentration ranging from 0.12 to 19.17 micrograms per 100 mg of protein. When 62 breast cancer specimens were categorised into four groups in terms of clinical stage, ir-PMN-E content in breast cancer tissue was significantly higher in stage III (8.90 +/- 5.13 micrograms 100 mg-1 protein) and stage IV (12.19 +/- 5.44 micrograms 100 mg-1 protein) patients than in stage I (1.64 +/- 1.54 micrograms 100 mg-1 protein) and stage II (4.23 +/- 3.74 micrograms 100 mg-1 protein) patients. Breast cancer patients with high levels of ir-PMN-E showed significantly shorter disease-free survival and overall survival than those with low levels of ir-PMN-E at the cut-off point of 8.99 micrograms 100 mg-1 protein. In the multivariate analysis, ir-PMN-E content was found to be a significant prognostic factor for disease recurrence and death in human breast cancer.

Prognostic significance of three novel biologic factors in a clinical trial of adjuvant therapy for node-negative breast cancer

BACKGROUND Five products of human breast carcinoma cells, including membrane-associated phospholipase A2 (M-PLA2), polymorphonuclear leukocyte elastase (PMN-E), tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), and endothelin-1 (ET-1), have been implicated in the processes of tumor cell invasion and metastasis in human breast carcinoma. However, the prognostic significance of these factors has not been assessed previously in node-negative breast carcinoma, in which adjuvant treatment is dependent on risk stratification. METHODS The five products of breast carcinoma cells were measured in 184 patients with node-negative breast carcinoma who were enrolled in the Kumamoto Adjuvant Chemo-Endocrine Therapy for Breast Cancer prospective randomized trial, and the predictive values of these factors for relapse-free and overall survival were evaluated. RESULTS M-PLA2, PMN-E, and t-PA were found to be significant independent predictors of relapse-free and overall survival, whereas u-PA and ET-1 were not independently predictive. Further statistical analyses showed that the predictive powers of M-PLA2, PMN-E, and t-PA were additive. A combination of these three factors identified a group of patients (approximately 50% of those who manifested node-negative breast carcinoma) with a favorable prognosis, regardless of the administration of adjuvant therapy. CONCLUSIONS This study identified three biologic factors that are valuable predictors of survival in node-negative breast carcinoma. A combination of these biologic factors may allow identification of low-risk patients who could be spared adjuvant therapy.

The sequence of vessel ligation affects tumor release into the circulation

OBJECTIVE Whether the sequence of pulmonary vein and artery ligation in pulmonary lobectomy for carcinoma affects intraoperative hematogenous cancer cell dissemination is not known. We examined whether vessel ligation sequence affects the presence of circulating cancer cells as reflected by carcinoembryonic antigen messenger ribonucleic acid. METHODS We assayed for the transcripts of carcinoembryonic antigen messenger ribonucleic acid by reverse-transcriptase polymerase chain reaction in peripheral blood taken before, during, and after operation from 30 patients with non-small-cell lung cancer who underwent a curative lobectomy and from six patients with limited-stage small-cell lung cancer who were treated initially with chemotherapy followed by lobectomy. Each patient was randomly assigned before the operation to have either pulmonary vein ligation or pulmonary artery ligation first. Blood taken from 10 patients with interstitial pulmonary fibrosis who underwent an open lung biopsy and 41 healthy subjects served as a control. RESULTS No control samples were positive for transcripts. Sixteen of the preoperative blood samples from the 30 patients with non-small-cell cancers were positive. Of these 16, eight samples remained positive even after lobectomy was performed; the remaining eight samples (four in each ligation group) became negative. Of the 14 initially negative samples (seven in each ligation group), nine samples became positive during the operation. Such conversion during the operation was more common with arterial ligation first (six patients, 85.7%) than with venous ligation first (three patients, 42.9%). Samples from all six patients with small-cell cancer were positive before the operation, and five of six samples remained positive after the operation. CONCLUSIONS Many patients with non-small-cell lung cancer have systemic disease even when they were thought to have resectable tumors. Ligating the pulmonary vein before ligating the artery may lessen intraoperative hematogenous dissemination. Most small-cell lung cancers represent systemic disease even when considered resectable.

Differential biological significance of tissue-type and urokinase-type plasminogen activator in human breast cancer.

Plasminogen activator (PA) is a serine protease existing in two forms known as tissue-type (t-PA) and urokinase-type (u-PA). To examine whether PA is related to the postoperative clinical course of human breast cancer, total PA activity, t-PA activity, u-PA activity, and immunoreactive t-PA were determined in tissue extracts from 144 breast cancer specimens. The patients were initially divided into four groups according to the postoperative clinical course: Group I (83 patients who are disease-free), Group II (20 patients whose first metastases were found only in bone), Group III (19 patients whose first metastases were found in both bone and lung), and Group IV (22 patients whose first metastases were found only in lung). Total PA activity was significantly lower in Groups, II, III and IV than in Group I. Both t-PA activity and t-PA antigen levels were also significantly lower in Groups II, III and IV than in Group I, while no significant difference was found in u-PA activity among these groups, indicating that low activity of total PA in Groups II, III and IV was due to a decrease in t-PA but not in u-PA. In the multivariate analyses, t-PA activity was found to be an independent prognostic factor for relapse-free survival. When four groups of patients were further analysed in terms of nodal status, both t-PA activity and antigen levels were markedly decreased in the node-negative Group II compared with the node-negative Groups III and IV or with the node-positive Groups II, III and IV. Of additional interest, u-PA activity was significantly higher in node-positive patients than in node-negative patients with any group. The clinico-pathologic analyses of the patients in this series showed that node involvement and lymphatic invasion were more frequently positive in Groups III and IV than in Groups I and II. When 144 breast cancers were categorised in terms of combinations of oestrogen receptor (ER) and progesterone receptor (PgR) status, breast cancers which were positive for both receptors were found to contain the highest t-PA activity and antigen. This study provides provocative evidence suggesting a possible differential significance of t-PA and u-PA expression in human breast cancer.

Medroxyprogesterone acetate treatment reduces serum interleukin-6 levels in patients with metastatic breast carcinoma.

The serum interleukin (IL)‐6 concentration was very low in patients with metastatic breast carcinoma who had received oral medroxyprogesterone acetate (MPA) treatment as compared with those who had not. Accordingly, the authors conducted a prospective study to determine whether MPA treatment reduces the serum level of IL‐6 in patients with this disease.