Ultrastructural features of large cell carcinoma of the lung with reference to the prognosis of patients

Intraoperative fine needle aspirations - diagnosis and typing of lung cancer in small biopsies: challenges and limitations

Background

Due to therapeutic implications with regard to both efficiency and safety of chemotherapy agents it is important to differentiate between subtypes of NSCLC. Up to today we experience a continuous reservation regarding the use of fine needle aspiration cytology. The aim of the present study is to estimate the value of cytologic criteria for lung cancer typing on small biopsies independent from all possible technique failures.

Methods

Between January 1997 and December 2008 760 intraoperative FNAC- (fine needle aspiration cytology) specimens from 702 patients have been examined. Cytologic evaluation and immediate communication of results to the surgeons followed. Afterwards, intraoperative cytologic findings were compared with final histologic diagnoses of the resected specimens.

Results

Intraoperative cytologic analysis yielded a sensitivity of 94.8 %, a specificity of 98.8 %. An overall positive predictive value of 99.8 % with respect to final histologic analysis of primary lung cancer was achieved. The highest value could be reached for adenocarcinomas, followed by carcinoids and squamous cell carcinomas.

Conclusions

Lung cancer typing according to cytologic criteria is feasible and accurate as well as comparable with results of histologic analysis on small specimens. Herewith, clinicians can come up to the increasing demands on minimally invasive harvested specimens with regard to therapeutic implications.

Distinct profile of driver mutations and clinical features in immunomarker-defined subsets of pulmonary large-cell carcinoma

Pulmonary large-cell carcinoma-a diagnostically and clinically controversial entity-is defined as a non-small-cell carcinoma lacking morphologic differentiation of either adenocarcinoma or squamous cell carcinoma, but suspected to represent an end stage of poor differentiation of these tumor types. Given the recent advances in immunohistochemistry to distinguish adenocarcinoma and squamous cell carcinoma, and the recent insights that several therapeutically relevant genetic alterations are distributed differentially in these tumors, we hypothesized that immunophenotyping may stratify large-cell carcinomas into subsets with distinct profiles of targetable driver mutations. We therefore analyzed 102 large-cell carcinomas by immunohistochemistry for TTF-1 and ΔNp63/p40 as classifiers for adenocarcinoma and squamous cell carcinoma, respectively, and correlated the resulting subtypes with nine therapeutically relevant genetic alterations characteristic of adenocarcinoma (EGFR, KRAS, BRAF, MAP2K1/MEK1, NRAS, ERBB2/HER2 mutations and ALK rearrangements) or more common in squamous cell carcinoma (PIK3CA and AKT1 mutations). The immunomarkers classified large-cell carcinomas as variants of adenocarcinoma (n=62; 60%), squamous cell carcinoma (n=20; 20%) or marker-null (n=20; 20%). Genetic alterations were found in 38 cases (37%), including EGFR (n=1), KRAS (n=30), BRAF (n=2), MAP2K1 (n=1), ALK (n=3) and PIK3CA (n=1). All molecular alterations characteristic of adenocarcinoma occurred in tumors with immunoprofiles of adenocarcinoma or marker-null, but not in tumors with squamous immunoprofiles (combined mutation rate 50% vs 30% vs 0%, respectively; P<0.001), whereas the sole PIK3CA mutation occurred in a tumor with squamous profile (5%). Furthermore, marker-null large-cell carcinomas were associated with significantly inferior disease-free (P<0.001) and overall (P=0.001) survival. In conclusion, the majority (80%) of large-cell carcinomas can be classified by immunomarkers as variants of adenocarcinoma or squamous cell carcinoma, which stratifies these tumors into subsets with a distinct distribution of driver mutations and distinct prognoses. These findings have practical implications for diagnosis, predictive molecular testing and therapy selection.

The Classification of Lung Carcinoma: Time to Change the Morphology-Based Approach?

Morphology still remains the cornerstone in lung cancer classification and always has been accompanying pathologists in their daily activity, even though several ancillary techniques have been incorporated over time to improve diagnostic, prognostic, and predictive capabilities in lung cancer. Currently, we are also faced with a global rethinking of lung cancer care, especially once novel therapy strategies have been made available on the basis of the diverse characteristics of tumors. Although morphology still remains a not easily replaceable tool for lung cancer classification, we are now challenged by the need of offering clinicians more detailed subtyping of non-small-cell lung cancer especially in event of limited diagnostic material, poorly differentiated tumors, or unresectable lesions. Close integration of improved morphology, immunohistochemistry, and molecular tests will be able to not only sharpen our diagnostic algorithms and prognostic and predictive potentialities but also get insights into several lung cancer biology issues, such as histogenesis and new classification schemes.

Histopathologic classification of lung cancer: Relevance of cytokeratin and TTF-1 immunophenotyping

Histopathologic classification of lung carcinoma is important, as a prognostic factor and in the evaluation of treatment modalities. Although the World Health Organization classification of lung cancer is based on routine microscopy, immunohistochemistry is an important additional aspect in modern pathologic practice. This study examines whether the main histologic types of lung carcinomas are more reliably diagnosed with immunohistochemical technique using antibodies for the lung tissue-specific antigen thyroid transcription factor-1 (TTF-1) and a panel of cytokeratin (CK) antibodies. Forty-five cases of lung cancer (12 squamous cell carcinoma, 13 small cell carcinoma, 11 adenocarcinoma, 9 large cell carcinoma [LCC]/pleomorphic carcinoma) were stained with antibodies to CK CAM5.2, CK5, CK7, CK20, and TTF-1. All 45 cases were positive with CAM5.2, 16 of 45 cases with CK5, 34 of 45 cases with CK7, 4 of 45 cases with CK20, and 29 of 45 with TTF-1. Squamous cell carcinoma (epidermoid carcinoma) had the immunophenotype CK5+/TTF-1-, and at least 20% were also positive with CK7. Most nonepidermoid tumors had the "lung-specific" phenotype CK5-/TTF-1+; all small cell carcinomas had the phenotype CK5-/CK8+/TTF-1+, all adenocarcinomas CK5-/CK7+/TTF-1+ and (more than 50%) of LCC CK5-/CK7+/TTF-1+. Thus, more than 50% of LCCs were of the same phenotype as adenocarcinomas. The immunophenotypes of the main histologic types of lung carcinoma are stable and highly reproducible. However, because of considerable overlapping, immunophenotyping should not be used alone for histopathologic classification of lung cancer, but only as an adjunct to light microscopy. It is also suggested that CK5+ lung carcinomas with basaloid features should be regarded as variants of squamous cell carcinoma and not as LCC.

Pathology of lung cancer

This article reviews current concepts in pathologic classification of lung cancer based on 1999 World Health Organization (WHO)/International Association for the Study of Lung Cancer (IASLC) classification. Preinvasive lesions including squamous dysplasia/carcinoma in situ, atypical adenomatous hyperplasia and diffuse idiopathic pulmonary neuroendocrine cell hyperplasia are discussed in addition to current concepts of bronchioloalveolar carcinoma and neuroendocrine tumors.

Medullary carcinoma of the breast: an ultrastructural morphometric study of nine cases

Ultrastructural and morphometric features of 10 medullary carcinomas of the breast (MC) were investigated. Cases with a long follow-up were selected by applying stringent histologic criteria. All tumors had a homogeneous appearance by light microscopy. Under transmission electron microscopy, they showed occasional intracellular lumen formation or keratinization. In one tumor squamous differentiation was prominent and diffuse. Tumors with lymph node metastases possessed over 40% more desmosomes than nonmetastatic tumors. The number of cells with three or more nucleoli per nuclear section was significantly higher in metastatic than in nonmetastatic tumors (p = .02). Classic cases of MC of the breast display a relatively uniform appearance. However, subtle differences can be identified between metastatic and nonmetastatic tumors by ultrastructural morphometry. Although these differences are not associated with changes in the outcome of patients in this study, they seem to bear some relationship to the peculiar behavior of MC.

Ultrastructural heterogeneity of lung carcinomas: representativity of samples for electron microscopy in tumor classification

Histologic heterogeneity of tumors is a well-known phenomenon, which has been repeated studied at the light microscopic level. Electron microscopy has been advocated as an adjunct in classification of tumors which pose difficulties on light microscopic classification. However, in view of tumor heterogeneity, it might be anticipated that the problem of sample error could detract from the usefulness of electron microscopy in tumor typing. Ultrastructural heterogeneity of tumors has thus far not been systematically investigated. We performed an ultrastructural randomized and blinded study of superficial and deep samples of 44 resected lung carcinomas, tumors which are notorious for their histologic heterogeneity. Neuroendocrine and squamous differentiation, as well as adenodifferentiation, were assessed separately and semiquantitatively in each sample. Twenty-six tumors showed more than one type of differentiation in at least one sample. However, in only two cases did the main type of differentiation differ between the two samples. A further nine cases showed one predominant differentiation type in both samples, but a similarly pronounced second differentiation type in one of the samples. Thus, in terms of ultrastructural diagnosis, the two samples showed a major discrepancy in two of 44 cases, and a minor discrepancy in nine of 44 cases. We conclude that ultrastructural heterogeneity of lung tumors is a common occurrence, but that it only rarely leads to totally different ultrastructural diagnoses.

Expression of gastrin-releasing peptide (human bombesin) gene in large cell undifferentiated carcinoma of the lung

Production of the growth factor gastrin-releasing peptide (GRP) or human bombesin has been shown to be a feature of neuroendocrine tumours of the lung, particularly small cell carcinoma, and is possibly responsible for the characteristically rapid growth of this tumour. Large cell undifferentiated carcinoma of the lung (LCC) is also characterized by rapid growth and there is increasing evidence that some LCCs exhibit neuroendocrine differentiation. We therefore investigated GRP/bombesin immunoreactivity and the expression of GRP gene in ten LCCs. Histologically, all were composed of large cells with abundant cytoplasm, open nuclei, and prominent nucleoli, and there was no evidence of squamous, glandular, or neuroendocrine differentiation. At the ultrastructural level, most showed squamous or glandular differentiation but none contained neuroendocrine granules. None of the tumours showed immunoreactivity for GRP/bombesin but seven of the ten showed a focal hybridization signal when treated with 32P-labelled GRP cRNA probes, indicating the presence of GRP mRNA. This was confirmed by northern blot analysis. This study shows for the first time that GRP gene is expressed in LCC. The production of GRP may contribute to the aggressive behaviour of LCC.

Clinical applications of the pathological properties of small cell carcinoma, large cell carcinoma, and adenoid cystic carcinoma of the lung

Lung cancer has considerable treatment problems, with a poor 5-yr survival rate after surgery. Application of histopathological and immunohistopathological subtyping have proven to be powerful tools for the assessment of prognosis. Results in 33 patients with small cell carcinoma, 44 with large cell carcinoma, and five with adenoid cystic carcinoma of the lung are discussed. The 5-yr survival rates in patients with small cell carcinoma of the oat cell type and intermediate type were 24 and 44%, respectively. Argyrophilic granules and neuron-specific enolase, neuroendocrine markers, were detected more frequently in the oat cell type rather than in the intermediate type. In contrast, keratin, epithelial membrane antigen, and carcinoembryonic antigen, epithelial origin markers, were present more frequently in the intermediate type than in the oat cell type. The 5-yr survival rates with large cell carcinoma of the compact growth type and the loose structure type were 46 and 28%, respectively, based on evidence of morphologically intercellular cohesion. The epithelial origin markers were detectable and more frequent in the compact growth type than in the loose structure type. The growth patterns of adenoid cystic carcinoma are classified as tubular, cribriform, and solid. The solid pattern was the most aggressive with extensive perineural invasion. We propose that the pathological properties of lung cancer should be examined as a prognostic implication of subtyping.

Reproducibility of tumour typing of lung carcinomas performed according to WHO's recommendation

Tumour sections from 139 patients with bronchial carcinoma were classified blindly by a panel of three pathologists according to the WHO recommendation of 1981. Only sections from resected specimens were included. There was agreement among all reviewers with regard to the main WHO tumour type of 71% of the specimens. For the remainder, two reviewers agreed upon 19% whereas the tumour classification differed substantially in 10% of all cases. About half of the original diagnoses were maintained when the latter group was re-evaluated blindly. Best agreement in the whole material was noted for squamous cell carcinoma. The main difficulty was differentiation between adenocarcinoma and squamous cell carcinoma with a high malignancy grading score. Despite the improvements of the WHO classification system, our group of diagnostic problem cases was not reduced when compared with earlier classification studies.

Adenocarcinoma of the lung: a comparative diagnostic study using light and electron microscopy

Several techniques for diagnosing adenocarcinoma of the lung are commonly available, but the frequency of their use and diagnostic sensitivity may vary. Twenty cases of primary lung adenocarcinoma obtained at surgery were studied by the following four routine techniques: light microscopy (LM) using hematoxylin-eosin (H&E) stain, mucicarmine stain, and PAS-diastase stain, and electron microscopy (EM). Three observers independently determined the positivity (0 [none], +/- [equivocal], 1 + [slight], 2 + [moderate], 3 + [marked]) of each of these cases for lumen formation in H&E-stained sections (LM lumens), intracytoplasmic (cytoplasmic mucicarmine) or intraluminal (luminal mucicarmine) mucicarmine, intracytoplasmic (cytoplasmic PAS) or intraluminal (luminal PAS) PAS-diastase, and lumen formation (EM lumens) or microvilli (EM microvilli) on electron microscopy. Comparative matching of these seven microscopic determinants (using Wilcoxon signed-rank test) demonstrated significant (P less than .01) sensitivity of EM microvilli over EM lumens, EM microvilli over luminal mucicarmine, cytoplasmic PAS over luminal mucicarmine, EM microvilli over cytoplasmic mucicarmine, cytoplasmic PAS over cytoplasmic mucicarmine, and EM microvilli over LM lumens, and a significant (P less than .05) sensitivity of cytoplasmic PAS over LM lumens, EM microvilli over luminal PAS, luminal PAS over luminal mucicarmine, and cytoplasmic PAS over EM lumens. Friedman's nonparametric test (P less than .05) indicated a significant difference among the microscopic determinants. The most sensitive was EM microvilli (mean rank score, 5.17) followed by cytoplasmic PAS (4.77), luminal PAS (4.02), cytoplasmic mucicarmine (3.62), LM lumens (3.52), EM lumens (3.47), and luminal mucicarmine (3.40). However, each of the diagnostic techniques had case examples positive for one, but not for the others, indicating that maximum yield of adenocarcinoma diagnoses will be obtained by performing all four techniques (H&E, mucicarmine, PAS-diastase, and electron microscopy.

Adenosquamous lung carcinoma: clinical characteristics, treatment, and prognosis

Adenosquamous carcinoma of the lung is a rare and poorly described entity. At the University of Chicago between 1974 and 1985, 2.3% (20/873) of patients with lung cancer had well-differentiated adenosquamous carcinoma. As in non-small cell lung cancer, patients with Stage I disease were amenable to operation with 60% (3/5) free from disease between one and six years postoperatively. However, Stage II adenosquamous carcinoma (14 patients) exhibited highly aggressive behavior with rapid progression of disease (mean interval, 2.1 months). Despite combinations of surgery (6 patients), chemotherapy (6 patients, one response), and radiotherapy (10 patients, no response), median survival for patients with Stage III adenosquamous carcinoma was 5.0 months, worse than that for Stage III small cell cancer (9.6 months), adenocarcinoma (9.0 months), and squamous cancer (7.8 months).

Atypical endocrine tumors of the lung: a histologic, ultrastructural, and clinical study of 19 cases

Lung cancers are divided by light microscopic criteria into several categories, but only two categories are recognized clinically--small cell and non-small cell carcinomas. Transmission electron microscopy has revealed unexpected complexity within each category, blurring the distinctions between them. The present study was undertaken to determine the incidence of dense-core, neuroendocrine-type granules in lung tumors diagnosed by light microscopy as non-small cell carcinomas, i.e., atypical endocrine tumors, and the clinical significance of their identification. Of 205 consecutive primary and metastatic lung cancers, 19 (9 per cent) diagnosed as non-small cell carcinomas by light microscopy were seen to contain neuroendocrine-type granules by electron microscopy and thus were reclassified as atypical endocrine tumors of the lung. Staining with silver stains, periodic acid-Schiff (PAS), PAS with diastase digestion, and mucicarmine was positive in 18, 15, 14, and eight of the 19 cases, respectively. Electron microscopy revealed glandular differentiation in 12 cases and tonofilaments in eight cases, although none of the tumors met the criteria for identification as squamous cell carcinomas. Clinically, the cancers appeared to resemble non-small cell carcinoma more closely than small cell carcinoma. Median survival (12 months) and response to combination chemotherapy (22 per cent) were in the range reported for non-small cell carcinoma. There were no complete responses, despite the use in some cases of regimens active against small cell carcinoma. However, one patient, the only one to date so treated, had a dramatic response to streptozotocin/5-fluorouracil, suggesting that, as in metastatic carcinoid, this combination may have value in the treatment of atypical endocrine tumors of the lung.

Large cell carcinoma of the lung. Ultrastructural and immunohistochemical features

Forty one cases of large cell anaplastic carcinoma of the lung (LCACL) were investigated by electron microscopy and immunoperoxidase studies for cytokeratin, enolase, and carcinoembryonic antigen. The results indicated that these neoplasias, grouped as an unique entity by ordinary histopathologic findings, may be further divided into five groups as follows: squamous, adenomatous, adenosquamous, neuroendocrine, and undifferentiated. The authors suggest that this subclassification may be useful in treatment orientation and in the prognostic evaluation of these neoplasias.

Establishment of a human large cell lung tumor line (QU-DB) with metastatic properties in athymic mice

A continuous human cell line was established from a patient with large cell anaplastic lung carcinoma. This cell line, designated QU-DB, has been in culture for over 36 months and grows as an adherent monolayer with a doubling time of 10-12 hours. Its morphology, ultrastructure, karyotype, ability to grow in soft agar and heterotransplantability, indicate it is a large-cell lung tumor cell line of human origin. Three cell lines were established from metastatic tumors in nude mice receiving subcutaneous injections of QU-DB cells. The morphology and growth characteristics exhibited by these cell lines were similar to the primary cell line. Karyotypic analysis of cell lines derived from the primary tumor and a metastasis to the diaphragm were similar, but cells from a liver metastasis culture showed additional karyotypic changes. This large cell lung tumor cell line may prove useful as a model system for studies of human tumor progression and metastasis.

Cellular heterogeneity in lung cancer

Sixty-six lung carcinomas have been examined by light and electron microscopy, as well as by immunocytochemical techniques using a panel of monoclonal antibodies. There was considerable heterogeneity with regard to cell type and in only 18 cases was it possible to classify the tumour as a solely small cell, squamous or adenocarcinoma. In the remaining cases there was evidence of two or three cell types. These findings support the thesis that all lung cancers are derived from a pluripotential basal or reserve cell in the bronchial mucosa which may proliferate along one or more lines of differentiation. This view of the histogenesis of lung cancer would account for the heterogeneous appearance of many tumours and the difficulty experienced in placing them in one of the standard classifications.

Use of a monoclonal antibody (B72.3) as a novel immunohistochemical adjunct for the diagnosis of carcinomas in fine needle aspiration biopsy specimens

Monoclonal antibody B72.3 has been shown to be reactive with a high-molecular-weight glycoprotein complex termed TAG(tumor-associated glycoprotein)-72. By the avidin-biotin immunoperoxidase method, fine needle aspirates and corresponding surgically excised tumor tissues from both malignant and benign tissues were analyzed for TAG-72 expression. Staining (range, 1 to 100 per cent of tumor cells) with monoclonal antibody B72.3 was observed in needle aspirates from 18 of 18 adenocarcinomas and adenosquamous carcinomas of the lung, 17 of 21 adenocarcinomas of the breast, and six of six adenocarcinomas of the colon, as well as adenocarcinomas from other body sites. In contrast, small cell carcinomas of the lung, malignant melanomas, lymphomas, and sarcomas did not stain with the antibody. Benign lesions from the breast, lung, pancreas, parotid, and thyroid also failed to stain. In 66 patients, tumor-bearing tissue had also been resected and was available for comparative examination with monoclonal antibody B72.3. In 62 of these 66 patients, the staining patterns in the aspirates were found to be predictive of the patterns of antibody reactivity in the comparable surgically resected tissues. From these studies it is concluded that monoclonal antibody B72.3 defines a tumor-associated antigen that is expressed in neoplastic cells but not in benign cells and is most selectively expressed in adenocarcinomas. This monoclonal antibody may be used as a novel adjunct for the diagnosis of carcinoma in fine needle aspiration biopsy specimens.

Giant cell carcinoma of the lung. Clinical and roentgenographic manifestations

Giant cell carcinoma of the lung is an unusual form of pulmonary malignancy that follows an extremely aggressive clinical course. We report the clinical and roentgenographic manifestations of 14 patients with pathologically proven giant cell carcinoma of the lung, and compare our data to other reports in the literature. Our patients often presented with or developed constitutional or nonthoracic symptoms. This neoplasm was characterized by early evidence of widespread metastases. However, extension of tumor to the chest wall was not as frequent in our series as has been previously described. The survival from the time of diagnosis was extremely short. Any hope of successful treatment of this neoplasm depends on prompt, early diagnosis. Pulmonary giant cell carcinoma should be included in the differential diagnosis of large, round or oval, sharply outlined peripheral lung masses.

Cytologic diagnosis of lung cancer. Principles and problems

This diagnostic seminar discusses the current status of the principles and problems of cytology as it is applied to the diagnosis of lung cancer. This discussion is divided into four major parts. Part I presents a discussion of cytopreparatory techniques and cytology of the lung in the absence of cancer. The cytology of benign proliferations which may mimic cancer is emphasized. The role of cytology in the diagnosis of pulmonary infectious organisms is noted. Part II discusses lung cancer as manifested in specimens of sputum, bronchial washings, and bronchial brushings. Part III presents some data on the validity of cytology with respect to role of specimen number and type in lung cancer diagnosis and cell typing in lung cancer. The continued usefulness and importance of multiple specimens of sputum for lung cancer diagnosis are documented. Part IV presents a brief synopsis of fine needle aspiration biopsy of lung cancer.

A high-grade malignancy bronchial mucoepidermoid carcinoma with features of giant cell carcinoma

A high-grade mucoepidermoid carcinoma associated with giant cell carcinoma of the bronchus was found in a 41-year-old man. Light and electron microscopic examinations showed glandular and squamous elements. The histology of the giant cell carcinoma was similar to those of previously reported giant cell carcinomas. It was assumed that the giant cell carcinoma in the present case is the result of transformation of mucoepidermoid carcinoma originating in the bronchial gland.

Large cell carcinoma of the lung. Ultrastructural differentiation and clinicopathologic correlations

Light microscopic biopsy specimens from 48 patients were reviewed by two independent pathologists and classified as large cell carcinoma of the lung by 1981 World Health Organization (WHO) criteria. Sites of primary disease were hilar/mediastinal in 26 patients, large mid-lung field in 17, and peripheral lung in 5. All material was examined by electron microscopy (EM) for evidence of squamous ("squamous": 15 patients), glandular ("adenocarcinoma": 17 patients), or nonspecific ("large cell": 14 patients) ultrastructural differentiation. Two patients had mixed adenosquamous features. There were 6 patients with Stage I tumors; 5, Stage II; 24, Stage IIIM0; and 13, Stage IIIM1. Of the 14 patients with large cell by EM, 11 had unresectable Stage IIIM0 or metastatic disease. Only 3 of 27 patients not undergoing resection responded to combined modality therapy. There were two long-term survivors free of disease in the resected Stage IIIM0 patient category. Overall median survival by stage was analyzed, with no statistically significant difference between several of the stage groupings, suggesting a worse prognosis for the entire group overall compared to all patients with non-small cell lung cancer. The median survival by EM subgroup was also without significant difference, both overall and within various stage groupings, despite more patients in the large cell category with advanced disease. These data support the unique behavior of patients with large cell carcinoma on light microscopy, but fail to demonstrate that ultrastructural differentiation is of prognostic importance for response or survival.

Lung cancer heterogeneity: a blinded and randomized study of 100 consecutive cases

The heterogeneity of lung carcinomas was recognized in the past, but few previous studies attempted to quantitate this heterogeneity. In the present study 100 consecutive cases of lung carcinoma (65 surgical resections and 35 autopsies) were collected, and either the entire tumor or ten blocks were examined in a blinded and randomized fashion using the revised (1981) WHO classification. At least three of five panelists agreed on the major histologic type present for 94 per cent of the slides. Agreement for the diagnosis of small cell carcinomas (at least four of five observers) was 98 per cent, but only 72 per cent agreement was attained for the subtyping of small cell carcinomas (e.g., oat cell versus intermediate). Only 34 per cent of the cases were homogeneous according to the majority of the panelists. An additional 21 per cent of the cases showed minor (subtype) heterogeneity (e.g., mixtures of acinar and papillary patterns in adenocarcinoma). Forty-five per cent of the cases showed major heterogeneity, i.e., at least one slide from the case showed a major histologic type different from that of the remainder. Seven small cell carcinomas were homogeneous, whereas in eight cases mixtures of small cell and other cell types were seen. In all but one of the cases involving bronchioloalveolar cell patterns, other patterns of adenocarcinoma were present elsewhere in the tumor. In all six cases involving giant cell carcinoma patterns, adenocarcinoma patterns were also present in some sections. Heterogeneity was identified by extensive sampling of the entire tumor and was seldom recognized in biopsy specimens.

Adenosquamous carcinoma of the lung: a clinical and pathologic study of seven cases

Adenosquamous carcinoma is a rare, but pathologically distinct, form of lung cancer. Seven cases involving unequivocal squamous and glandular differentiation were studied. These cases accounted for 0.6 per cent of the 1,125 primary lung cancers examined at a metropolitan hospital during a 15-year period. The tumors measured from 1.3 to 5.5 cm in diameter. Five were peripheral, and two were associated with scars. Three of five resected specimens had regional lymph node metastases. Five patients had died of the disease within two years of diagnosis, and two were short-term survivors.

Establishment and characterization of cell lines from human small cell and large cell carcinomas of the lung

Five new small cell carcinomas (SCC) cell lines and a large cell carcinoma (LCC) cell line were established from human lung cancers. The SCC cell lines had, as a group, common phenotypic properties which distinguished them from non-SCC cell lines. However, the studies also revealed a considerable biological heterogeneity among the individual SCC cell lines. Thus, the SCC cell lines had a typical growth pattern with cell clusters in suspension or partly adherent to the bottom. All the lines examined grew in agarose with variable cloning efficiencies, and all but one line formed tumors subcutaneously in nude mice. The ultrastructure of the SCC cell lines was characteristic with dense core granules at a variable frequency. Neuron-specific enolase was detectable in all SCC cell lines, usually in large amounts, and an inconstant production of a spectrum of polypeptide hormones was found, typical of SCC. The LCC cells proliferated in monolayers, formed colonies in agarose and grew in nude mice. Ultrastructurally, the LCC cell line differed from the SCC cell lines in having intra- and intercellular lumina and tonofilaments. The capacity of the LCC and a previously established squamous cell carcinoma cell line (U-1752) to produce neuron-specific enolase and polypeptide hormones was characteristically much lower than that of the SCC cell lines. We conclude from this study that SCC cell lines, although individually distinct from one another, are quite homogeneous as a group in expressing a set of basic common neuro-endocrine markers. However, these studies also suggest some biological relationship between SCC, LCC and SQC by virtue of their expression of some common neuro-endocrine markers, in support of the concept of a common histogenetic origin of human lung cancers.

Monoclonal antibodies specific for two different histological types of human lung carcinoma

Hybridomas secreting monoclonal antibodies specific for human lung cancer were produced by fusing immunized mouse spleen cells with mouse myeloma line X63-Ag8.653. Prior to fusion, BALB/c mice were immunized with two different histological types of human lung cancer (Squamous cell carcinoma and adenocarcinoma) obtained from surgery. An immunocytoadherence test was used to select hybridomas secreting antibodies that bound the patient's lung tumor, but did not bind to a B-lymphoblastoid cell line derived from the same patient. Five stable antibody-producing hybrids have been established and cloned. The antibodies produced by these clones have been characterized according to their light and heavy chain isotypes and for their specificity. In addition to binding to the tumor used for immunization, the antibodies bound to other lung tumors of the same histological type (i.e., squamous cell or adenocarcinoma). This reactivity was observed with both established lung tumor cell lines and with fresh tumors obtained from biopsy of patients in our clinic. Some significant reactivity was also observed with large cell carcinoma but the antibodies did not react with small cell carcinomas of the lung, bronchiolo-alveolar cell carcinoma, cancer of the esophagus and stomach, melanomas, several types of leukemias, normal human lung tissue, fibroblasts, or erythrocytes of type A, B, or O. Two of the five antibodies, 5C7 and 5E8 cross-reacted with one breast cancer obtained from surgery, and 5C7 also cross-reacted with one melanoma biopsy specimen. These results suggest that we have generated monoclonal antibodies that recognize a set of antigenic determinants that are commonly expressed on a portion of human lung tumors that are not detectable on a variety of other human tumors or normal human tissue.

Carcinoma of the lung: evaluation of histological grade and factors influencing prognosis

The results in 96 patients with lung cancer who underwent lobectomy or pneumonectomy were analyzed. In reviewing the case histories of these patients, it became apparent that those with poorly differentiated tumor (grade 3) have an increased likelihood of positive lymph node metastases compared with those with well-differentiated (grade 1) or moderately differentiated (grade 2) tumor. Poor differentiation of the tumor, vascular invasion, and lymph node metastases appear to represent poor prognostic indices in patients undergoing operation. Compared with patients with grade 1 and grade 2 tumors, patients with a grade 3 adenocarcinoma had more local recurrences, while those with grade 3 squamous cell carcinoma had more distant metastases. The findings suggest that histological grading is an important adjunct to the clinical evaluation of and planning of treatment for patients with lung cancer.