Applications of monoclonal antibodies in clinical cytology as exemplified by studies with monoclonal antibody B72.3. The George N. Papanicolaou award lecture

The monoclonal antibody (MAb) B72.3, reactive with a high-molecular-weight, glycoprotein, tumor-associated antigen, designated TAG-72, has been previously shown to be reactive with formalin-fixed, paraffin-embedded tissue sections of adenocarcinomas of the ovary, colon and breast, but not a variety of normal adult tissues. It has demonstrated utility as an immunocytochemical adjunct for the diagnosis of carcinoma in cell blocks and cytocentrifuge preparations of human serous effusions, with selective reactivity for tumor cells (particularly adenocarcinoma) over reactive mesothelium. Using the avidin-biotin complex (ABC) method of immunoperoxidase staining and formalin-fixed, paraffin-embedded cell suspensions, MAb B72.3 detected tumor cells in effusions from all of 21 patients with adenocarcinoma of the breast. No reactivity was demonstrated in any cell type in benign effusions from 41 patients. In contrast, MAb B72.3 showed no reactivity to leukemic or lymphomatous effusions, or to mesothelial cells from malignant effusions. MAb B72.3 also detected adenocarcinoma cells in effusion specimens from 12 of 12 patients with adenocarcinoma of the lung and 16 of 16 patients with adenocarcinoma of the ovary. MAb B72.3 has recently been used with fine needle aspiration (FNA) biopsy specimens and the corresponding surgically excised tumors to determine cellular reactivity. Using the ABC immunoperoxidase method, fine needle aspirates and corresponding surgically excised tumors were analyzed for TAG-72 expression. Positive staining with MAb B72.3 was observed in needle aspirates of 27 of 27 adenocarcinomas and adenosquamous carcinomas of the lung, 17 of 21 adenocarcinomas of the breast, 6 of 6 adenocarcinomas of the colon and in carcinomas from other body sites. In contrast, 21 small-cell carcinomas of the lung, 13 malignant melanomas, 2 lymphomas and 2 sarcomas did not stain with the antibody. Benign lesions from the breast, lung, pancreas, parotid and thyroid also showed no staining. In many patients, tumor-bearing tissue had also been resected and was available for comparative examination with MAb B72.3. In more than 90% of these patients, the staining patterns of the tumor cells in the aspirates were found to be predictive of the patterns of antibody reactivity in the comparable surgically resected tumors. From these studies, it is concluded that MAb B72.3 defines a tumor-associated antigen that is expressed in neoplastic cells versus benign cells, that is most selectively expressed in carcinomas and that may be used as a novel adjunct for the diagnosis of neoplasms in effusions and in fine needle aspiration biopsies.     

Malignant melanoma in fine needle aspirates and effusions. An immunocytochemical study using monoclonal antibodies

The value of monoclonal antibodies (MAbs) for the immunodetection of keratin, vimentin and two melanoma-associated antigens recognized by NKI/C3 and NKI/Bteb for the diagnosis of malignant melanoma has been previously established on histologic preparations. In the present study, cytologic preparations from 20 fine needle aspirates and effusions from patients with malignant melanoma were evaluated using these antibodies. Twenty of 20 smears were negative for keratin, and 20 of 20 smears were positive for vimentin. Positivity for NKI/C3 was seen in 12 of 12 cases studied, and for NKI/Bteb in 12 of 13 cases. These results indicate that a panel of MAbs consisting of anti-keratin, anti-vimentin, NKI/C3 and NKI/Bteb is useful for a more accurate diagnosis of malignant melanomas on cytologic preparations. The expression of these antigens in melanoma cells in cytologic smears can be a valuable aid in the detection of primary (noncutaneous) and metastatic melanomas by fine needle aspiration.     

Macrophage size determinations in the diagnosis of tuberculous effusions

This study investigated the usefulness of macrophage size determinations in lymphocyte-rich pleural effusions to improve the cytologic diagnosis of tuberculous pleurisy. The size of pleural macrophages was analyzed by quantitative morphometric planimetry in 18 effusions due to tuberculosis, 21 effusions following radiotherapy for malignant disease and 10 effusions due to congestive heart failure. Macrophages were identified and clearly separated from mesothelial cells by latex phagocytosis and immunostaining with the monoclonal antibody My4 (CD14). The mean macrophage area (+/- standard deviation) in tuberculous effusions (92 +/- 14 sq micron) was significantly smaller than in postradiation (141 +/- 28 sq micron) and heart-failure effusions (154 +/- 22 sq micron) (P less than .0001). There was also a smaller ratio of mesothelial cells in tuberculous effusions (0.5 +/- 0.9%) in comparison with effusions following radiotherapy (4 +/- 5%) or congestive heart failure (10 +/- 12%). In summary, this study demonstrated some cytomorphologic parameters that may be helpful in the differential diagnosis of tuberculous effusions.     

Desmoplastic small round cell tumour: Cytological and immunocytochemical features

BACKGROUND: Desmoplastic small round cell tumor (DSRCT) is a rare and highly aggressive neoplasm. The cytological diagnosis of these tumors can be difficult because they show morphological features quite similar to other small round blue cells tumors. We described four cases of DSRCT with cytological sampling: one obtained by fine needle aspiration biopsy (FNAB) and three from serous effusions. The corresponding immunocytochemical panel was also reviewed. METHODS: Papanicolaou stained samples from FNAB and effusions were morphologically described. Immunoreaction with WT1 antibody was performed in all cytological samples. An immunohistochemical panel including the following antibodies was performed in the corresponding biopsies: 34BE12, AE1/AE3, Chromogranin A, CK20, CK7, CK8, Desmin, EMA, NSE, Vimentin and WT1. RESULTS: The smears showed high cellularity with minor size alteration. Nuclei were round to oval, some of them with inconspicuous nucleoli. Tumor cells are clustered, showing rosette-like feature. Tumor cells in effusions and FNA were positive to WT1 in 3 of 4 cytology specimens (2 out 3 effusions and one FNA). Immunohistochemical reactions for vimentin, NSE, AE1/AE3 and WT1 were positive in all cases in tissue sections. CONCLUSION: The use of an adjunct immunocytochemical panel coupled with the cytomorphological characteristics allows the diagnosis of DSRCT in cytological specimens.     

Diagnosis of abdominal masses with percutaneous biopsy guided by ultrasound.

OBJECTIVE--To assess the accuracy and safety of percutaneous biopsy of abdominal masses guided by ultrasound. DESIGN--Prospective study. SETTING--Combined gastroenterology service, Scarborough Hospital. PATIENTS--108 Consecutive patients identified as having a discrete mass on diagnostic ultrasound examination of the abdomen. INTERVENTION--A sample of tissue was obtained with an aseptic technique under local anaesthesia: an 18 steel wire gauge needle (Tru-Cut) was mounted in a spring loaded firing device (Biopty gun) that was advanced under simultaneous ultrasound scanning, permitting precise localisation of the target organ. MAIN OUTCOME MEASURE--Results of histological examination of tissue specimens. RESULTS--Biopsy failed in four patients. Adequate histological specimens were obtained in 104 patients with masses in the liver (31), pancreas (37), kidney (10), and adrenal glands (six) and in 20 undiagnosed abdominal and retroperitoneal masses. Follow up was until death or confirmation of the diagnosis. Three complications but no deaths occurred. Malignancy was suspected in 84 patients before biopsy. This was confirmed in 70 patients, in 26 of whom confirmation of dissemination obviated the need for further investigation. In 10 patients biopsy indicated a previously unsuspected primary tumour, and in 12 it showed only a benign lesion. Among 24 patients considered to have benign disease biopsy showed an unsuspected neoplasm in seven. Use of biopsy thus had a major effect on clinical management in 55 patients. Four false negative but no false positive diagnoses resulted from the procedure. CONCLUSION--Percutaneous biopsy of abdominal and retroperitoneal masses under ultrasound guidance is a safe and accurate method of obtaining a histological diagnosis. The results obtained have a considerable effect on clinical management.     

MN/CA9: a potential gene marker for detection of malignant cells in effusions.

Many cancers cause malignant effusions. The presence of malignant cells in effusions has implications in diagnosis, tumour staging and prognosis. The detection of malignant cells currently presents a challenge for cytopathologists. New adjunctive methods are needed. Although the effusions provide excellent materials for molecular assay, the available molecular markers are extremely limited, which hinders its clinical application. MN/CA9 has proved to be a valuable marker in many cancers such as lung, breast, colon, kidney, etc. The present study was to evaluate MN/CA9 as a new molecular marker for the detection of cancer cells in pleural effusions. Seventy-one pleural effusions including 59 malignant effusions from patients with cancer, and 12 patients with benign diseases as a control, were subjected to RT-PCR for detection of MN/CA9 gene expression. MN/CA9 gene expression was detected in 53/59 (89.8%) pleural effusions from cancer patients (15/16 for breast cancers, 10/11 for lung cancers, 4/4 for ovary cancers, 2/3 for colon-rectal cancers, 5/6 for cancers of unknown site, 7/8 for mesothelioma and 10/11 for other cancers). Furthermore, MN/CA9 was positive in 13/18 (72.2%) of cytologically negative effusions of cancer patients. MN/CA9 was detected in only 1/12 (8.3%) effusions from the control patients (p < 0.01). The sensitivity and specificity of MN/CA9 gene expression were, respectively, 89.8% and 91.7%. Our preliminary results suggest that MN/CA9 could be a potential marker for the detection of malignant cells in effusions. A large-scale study is needed to confirm these results.     

MN/CA9: a potential gene marker for detection of malignant cells in effusions

Many cancers cause malignant effusions. The presence of malignant cells in effusions has implications in diagnosis, tumour staging and prognosis. The detection of malignant cells currently presents a challenge for cytopathologists. New adjunctive methods are needed. Although the effusions provide excellent materials for molecular assay, the available molecular markers are extremely limited, which hinders its clinical application. MN/CA9 has proved to be a valuable marker in many cancers such as lung, breast, colon, kidney, etc. The present study was to evaluate MN/CA9 as a new molecular marker for the detection of cancer cells in pleural effusions. Seventy-one pleural effusions including 59 malignant effusions from patients with cancer, and 12 patients with benign diseases as a control, were subjected to RT-PCR for detection of MN/CA9 gene expression. MN/CA9 gene expression was detected in 53/59 (89.8%) pleural effusions from cancer patients (15/16 for breast cancers, 10/11 for lung cancers, 4/4 for ovary cancers, 2/3 for colon–rectal cancers, 5/6 for cancers of unknown site, 7/8 for mesothelioma and 10/11 for other cancers). Furthermore, MN/CA9 was positive in 13/18 (72.2%) of cytologically negative effusions of cancer patients. MN/CA9 was detected in only 1/12 (8.3%) effusions from the control patients (p<0.01). The sensitivity and specificity of MN/CA9 gene expression were, respectively, 89.8% and 91.7%. Our preliminary results suggest that MN/CA9 could be a potential marker for the detection of malignant cells in effusions. A large-scale study is needed to confirm these results.     

Specific tumor markers in diagnostic cytology. Immunoperoxidase studies of carcinoembryonic antigen, lysozyme and other tissue antigens in effusions, washes and aspirates

The immunoperoxidase technique was used to identify specific tumor markers in exfoliated cells in fine needle aspirates and body fluids. Carcinoembryonic antigen (CEA) and lysozyme staining was evaluated in cytocentrifuge preparations from 42 malignant effusions and aspirates and 16 benign effusions. Reactive mesothelial cells were negative for CEA and lysozyme or showed faint peripheral cytoplasmic staining. Malignant cells from 50% of the adenocarcinomas studied were positive for CEA. All tumors studied were negative for lysozyme. These staining patterns are helpful in the differential diagnosis of reactive mesothelial and adenocarcinoma cells, a frequent diagnostic dilemma. Moreover, demonstration of specific tumor antigens (e.g., prostatic acid phosphatase, calcitonin and immunoglobulin) helped define the origin of metastatic malignancy in selected cases. Estrogen receptor activity was also identified in tumor cells using this technique. Immunoperoxidase was helpful in the evaluation of malignant cytologic specimens from patients with more than one tumor. Interpretation of staining patterns is discussed, with reference to the limitations of the technique. Immunoperoxidase methods maintain cytologic detail, are readily adaptable to diagnostic cytology and increase the specificity of cytologic diagnosis.     

The cytologic diagnosis of malignant neoplasms in pleural and peritoneal effusions

This study presents data on 3,011 pleural and peritoneal effusion specimens that were examined over a three-year period (1982 to 1984). Totals of 812 (44%) of 1,846 pleural and 423 (36%) of 1,165 peritoneal specimens were positive for malignant cells. While 535 patients had malignant pleural effusions, 254 patients had malignant peritoneal effusions, and 57 had both malignant pleural and peritoneal effusions. The most common primary neoplasms causing malignant pleural effusions were carcinomas of breast (24%) and lung (19%) and lymphoreticular neoplasms (16%). The most common primary neoplasms causing malignant peritoneal effusions were carcinomas of ovary (32%) and breast (13%) and lymphoreticular neoplasms (7%). There was an average interval of more than 30 months between the histologic diagnosis of the primary neoplasm and the diagnosis of malignant effusions in patients with carcinoma of breast, lymphoreticular neoplasm and malignant melanoma. The average time until death following the diagnosis of a malignant effusions was five months or less, except for patients with carcinoma of the breast and carcinoma of the ovary. One hundred twenty-five patients (15%) presented with malignant effusions caused by neoplasms of unknown primary sites. The most common primary neoplasms that were later diagnosed were, in decreasing order of frequency, carcinoma of the ovary, carcinoma of the lung and lymphoreticular neoplasms.     

Immunochemical demonstration of keratin and vimentin in cytologic aspirates

Antibodies to intermediate filament proteins were used to characterize tumor cells present in peritoneal and pleural effusions and in thin needle aspirates from palpable lymph nodes. Metastatic adenocarcinoma cells (breast, ovary, endometrium, cervix, colon and stomach) as well as squamous-cell carcinomas and mesotheliomas stained specifically with antibodies to keratin while mesenchymally derived tumor cells (lymphomas, melanoma, fibrosarcoma and neurofibrosarcoma) were positive only for vimentin. Especially in cases of lymph node aspirates, keratin staining in cells was a direct indication of metastatic carcinoma. Antibodies to these different components of the cytoskeleton can thus be used in cytopathologic diagnosis when a definitive diagnosis cannot be made on the basis of conventional cytologic features.     

Diagnostic imaging of small amounts of pleural fluid: pleural effusion vs. physiologic pleural fluid

The aim of this article is to present an overview of our 10 years clinical research work and early clinical experience with small pleural effusions. Small amounts of pleural fluid are severely difficult to identify with imaging methods (chest x-rays and ultrasound). Nevertheless, it may be an important finding, sometimes leading to a definitive diagnosis of pleural carcinomatosis, infection or other pathologic condition. Chest x-rays were used for many years for the diagnosis of small pleural effusions. Lateral decubitus chest radiographs represented a gold standard for imaging of small amounts of plural fluid for more than 80 years. In the last two decades, ultrasonography of pleural space became a leading real-time method for demonstrating small pleural effusions. Furthermore, the advent of sonographic technology actually enables detection of physiologic pleural fluid in some otherwise healthy individuals. In conclusion, new definitions of the key terms in the field of diagnostic imaging of small amounts of pleural fluid seem to be justified. We suggest that the term pleural fluid should determine physiologic pleural space condition while the term pleural effusion should only be used in the cases of pleural involvement or pleural illness.     

Diagnostic accuracy of cytology and immunocytology in carcinomatous effusions

Background: Immunocytology substantially improves the diagnostic accuracy of conventional cytology in the diagnosis of carcinomatous effusions. Due to the unequivocal characterization of the various cell populations, a sensitivity of 92% and specificity of 100% was achieved by immunocytology, examining samples of 1234 serous effusions. Objective: Cytology plays a central role in the aetiological clarification of serous effusions. The sensitivity of this method for the diagnosis of carcinomatous effusions varies between 40% and 80%. The aim of the present study was to investigate whether immunocytology substantially improves the diagnostic quality of the cytological examination in the diagnosis of carcinomatous effusions. Method: Consecutive serous effusions were examined by conventional cytology and by immunocytology. The immunocytological examination was performed on smears, using a standard panel of three antibodies against pancytokeratin, human epithelial antigen 125 and calretinin. Results: Altogether, 1234 effusion samples were examined. A total of 603 effusions were caused by carcinomas, five by malignant mesotheliomas, 11 by malignant lymphomas and 615 by non‐malignant disorders. In conventional cytology, carcinomatous effusions were correctly diagnosed in 314 samples, corresponding to a sensitivity of 52%. In 31 specimens (5%) tumour cells without further specification were described and in 161 samples (27%) the presence of tumour cells was suspected (84% overall sensitivity). A total of 97 carcinomatous effusions (16%) were diagnosed false‐negatively and 50 (8%) of the 615 non‐malignant effusions false‐positively (92% specificity). In immunocytology, 561 carcinomatous samples were correctly diagnosed, representing a sensitivity of 93%. In six cases (1%) the presence of tumour cells was suspected. A total of 36 carcinomatous effusions (6%) were diagnosed false‐negatively (94% over‐all sensitivity). Out of the 615 non‐malignant specimens, there were no false‐positive diagnoses (100% specificity). Conclusion: Immunocytology is a simple, cost‐effective, routinely practicable method which substantially improves the diagnostic accuracy of conventional cytology in the diagnosis of carcinomatous effusions. Therefore, we recommend the use of immunocytology in all those cases where cytology on its own is not completely unequivocal.     

Cytologic findings in a fetal intracranial teratoma. A case report

BACKGROUND: Fetal neoplasms are very rare. Recently we had the opportunity to examine the fine needle aspiration (FNA) biopsy of a fetal intracranial teratoma. CASE: The tumor was found in a 30-week-gestation fetus; the mother was 32 years old, gravida 4, para 1. She presented with a rapid increase in abdominal girth over a two-week period. An ultrasound scan showed severe fetal hydrocephalus and a massive intracranial tumor thought to be a teratoma because of variations in echogenicity and spotty calcification. An FNA biopsy was performed under ultrasound guidance. It showed mainly neuroepithelial cells, so a differential diagnosis of malignant neuroepithelial tumor was considered. At autopsy, several other tissue types were found in the tumor, consistent with a teratoma. CONCLUSION: Advances in diagnosis of fetal anomalies by ultrasound have been associated with an increase in the use of fetal interventions performed in utero. This includes the availability of fetal surgery in some centers. FNA biopsy of fetal lesions does not appear to be well described. Increased experience with this technique is necessary if its full potential is to be realized.     

DNA analysis of malignant effusions. Comparison with cytologic diagnosis and carcinoembryonic antigen content.

Twenty-three consecutive malignant effusions from 19 patients submitted for cytologic examination were analyzed for carcinoembryonic antigen (CEA) content and for DNA analysis by flow cytometry. The study was undertaken to determine if the addition of DNA analysis would improve the sensitivity of cytologic diagnosis and CEA assay. CEA examination was performed on Papanicolaou-stained smears and hematoxylin-and-eosin-stained cell blocks. Final diagnoses were correlated with histologic examination (four patients), clinical and radiologic studies, and follow-up. The malignant effusions in 19 patients were secondary to carcinoma of the breast (5), lung (5), ovary (1), endometrium (1), mucinous carcinoma of the colon (1), unknown primary (1), extraovarian papillary carcinoma (1), mesothelioma (2) and large cell lymphoma (2). The sensitivity of cytologic diagnosis was 100% and specificity 100%. DNA aneuploidy, defined as the presence of two separate peaks in the histogram, was present in 7 of 23 fluids (sensitivity, 30%). Four fluids had insufficient cells for analysis, and one histogram showed debris (following chemotherapy). DNA aneuploidy was detected in effusions secondary to carcinoma of the breast (4), lung (1) and lymphoma (2). Using 5 ng/mL as the cutoff, the sensitivity of CEA was 68%. DNA analysis of cells in malignant effusions is less sensitive than cytologic diagnosis, and CEA assay and is not recommended for routine use in the diagnosis of malignant effusions.     

Ultrasound evaluation of the hemothorax of patients operated on for pulmonary tuberculosis and control of the development of fibrous thorax

The paper deals with the ultrasound study of the hemothoracic cavity in pulmonary tuberculosis patients undergone pulmonectomy. Ultrasound study provides objective data on the time course of processes occurring the hemothorax operated on and controls the development of fibrothorax, such as the formation of effusions, in all its details.     

快速现场细胞学评价在经支气管针吸活检术诊断肺部良恶性疾病的临床应用

目的:超声引导下的经支气管针吸活检术(Endobronchial ultrasound guided transbronchial needle aspiration, EBUS-TBNA)是临床上广泛开展的经支气管的微创介入技术,在EBUS-TBNA过程中,快速现场细胞学评价(Cytologicalrapidon-siteevaluation,C-ROSE)是切实可行的临床辅助技术。本研究探讨C-ROSE在EBUS-TBNA对肺部疾病诊断的细胞学特点及诊断价值。方法:对41例经胸部计算机断层扫描(Computed tomography,CT)发现存在纵隔和(或)肺门病灶(包括肿大的淋巴结/肿块)而行EBUS-TBNA及C-ROSE患者进行回顾性分析。结果:C-ROSE镜下的细胞学具有明显特点,对肺部良恶性疾病的穿刺成功率无差异,诊断率分别为90.48%和66.67%(P0.05),且C-ROSE可完全排除恶性疾病的诊断,二组并发症发生率分别为9.52%和6.67%(P0.05)。结论:C-ROSE在EBUS-TBNA中对肺部良恶性病变均具有诊断价值,可以提高穿刺成功率及诊断率、减少并发症,值得在临床医疗介入中心推广。     

The Ultrasonic Evaluation of Nonfunctioning Thyroid Nodules

Thyroid echography was carried out on 100 patients with thyroid abnormalities to evaluate the diagnostic accuracy of ultrasound in differentiating simple thyroid cysts from solid thyroid nodules.In all 46 proven cases, the ultrasonic diagnosis of the solid or cystic nature of thyroid nodules was correct.A proposed diagnostic workup of a hypofunctioning (cold) thyroid nodule is suggested with primary needle aspiration and cytologic examination of the cyst fluid being recommended if the nodule is shown to be entirely cystic by ultrasound.     

Cytologic presentation of malignant mesothelioma in pleural effusions

1,601 pleural effusions were found to be malignant between 1976 and 1987. Among these were 26 (1.6% of the malignant effusions) mesothelioma. Only 2 cases showed pronounced cytologic features that made a definite diagnosis possible on cytologic criteria alone. In 20 cases diagnosis of mesothelioma was strongly suggested by the patient's history and cytology of the effusion was compatible with mesothelioma. In the other 4 cases special examinations (histo- and immunohistochemistry, electron microscopy) led to the final diagnosis. The cytologic features of mesothelioma and other examination techniques, needed to resolve the differential diagnosis of mesothelioma versus other neoplasm in pleural effusions, are discussed.     

Fine needle aspiration cytology of the thyroid: a comparison of 5469 cytological and final histological diagnoses

OBJECTIVE: We evaluated the efficacy of fine needle aspiration cytology (FNAC) of the thyroid in a series of 5469 lesions with histological control and studied the causes of, and the possibility of reducing the limitations of the method. METHODS: FNAC was always performed by a pathologist under the guidance of a clinician, using a 22-gauge needle. Generally two aspirations were carried out, and usually four slides were obtained for each nodule; they were then stained with May-Grünwald-Giemsa and with Papanicolaou. The cytological diagnoses were classified in four groups: inadequate, benign, suspicious and malignant. RESULTS: We obtained a complete sensitivity of 93.4%, a positive predictive value of malignancy of 98.6%, and a specificity of 74.9%. At histological control, the cytological diagnosis of Hurthle cell neoplasm corresponded to a significantly higher incidence of malignant neoplasms than the diagnosis of non-Hurthle cell follicular neoplasm (32.1% versus 15.5%). There were 66 false-negative findings, the main cause of diagnostic error (24 cases) being failure to recognize the follicular variant of papillary carcinoma. The number of inadequate FNACs was low (4.2%). CONCLUSION: Our study confirmed the great efficacy of thyroid FNAC. A cytological diagnosis of Hurthle cell neoplasm should be considered an indicator of high risk. Awareness that failure to recognize the follicular variant of papillary carcinoma was the main problem in the interpretation of thyroid FNAC should lead to a decrease of false-negative diagnoses. The inadequate rate was very low, as it was the pathologist personally who performed the needle aspiration.     

Configuration of surfaces of human cancer cells obtained by fine needle aspiration biopsy: a comparative light microscopic and scanning electron microscopic study

The surface configuration of human cancer cells removed from their natural setting by fine needle aspiration biopsies was studied by scanning electron microscopy. Cells from several carcinomas of the breast, malignant melanomas, oat cell carcinomas and a malignant lymphoma were the subject of this study. Only viable cells, identified by light microscopy prior to scanning, were selected for study. Contrary to prior observations on cancer cells in effusions, the surface configuration of human cancer cells obtained directly from tissues is variable and may depend significantly on the histologic patterns.