Ultrastructural and immunohistochemical studies of bronchiolo-alveolar carcinoma

Polymeric immunoglobulin receptor (pIgR) in cancer

BACKGROUND

The polymeric immunoglobulin receptor (pIgR) is a transmembrane transporter of polymeric IgA through the intestinal epithelium. Its overexpression has been reported in several cancers, but its role as a diagnostic and prognostic biomarker of oncogenesis is currently unclear.

METHOD

A literature search was conducted to summarize the functions of pIgR, its expression levels, and its clinical implications.

RESULTS

pIgR expression has previously been investigated by proteomic analysis, RNA sequencing, and tissue microarray at the level of both RNA and protein in various cancers including pancreatic, esophageal, gastric, lung, and liver. However, studies have reported inconsistent results on how pIgR levels affect clinical outcomes such as survival rate and chemotherapy resistance. Possible explanations include pIgR mRNA levels being minimally correlated with the rate of downstream pIgR protein synthesis, and the diversity of antibodies used in immunohistochemistry studies further magnifying this ambiguity. In ovarian cancer cells, the transcytosis of IgA accompanied a series of transcriptional changes in intracellular inflammatory pathways that inhibit the progression of cancer, including the upregulation of IFN-gamma and downregulation of tumor-promoting ephrins. These findings suggest that both the levels of pIgR and secreted IgA from tumor-infiltrating B cells affect clinical outcomes.

CONCLUSION

Overall, no direct correlation was observed between the levels of pIgR inside tumor tissue and the clinical features in cancer patients. Measuring pIgR protein levels with a more specific and possibly chemically defined antibody, along with tumoral IgA, is a potential solution to better understand the pathways and consequences of pIgR overexpression in cancer cells.

Morphological Characterization of Lewis Lung Carcinoma (3LL). A Light and Electron Microscopic Study

Primary tumor and its metastases of subcutaneously injected Lewis lung carcinoma (3LL) of the mouse were examined by light and electron microscopy. Although the optical appearance, in both cases, was of a indiffentiated carcinoma, the ultrastructural observation showed characteristic intracyto-plasmic myelinoid bodies similar to those seen in type II pneumocytes in normal lung. These findings suggest that Lewis lung carcinoma is a carcinoma derived from granular pneumocytes equivalent to human alveolar cell carcinoma. The histological and embryological aspects ot type II pneumocytes that could explain the histogenesis of this tumor are discussed.

Loss of polymeric immunoglobulin receptor expression is associated with lung tumourigenesis

Polymeric immunoglobulin receptor (pIgR) expression is downregulated in lung cancer, but its implications in lung tumourigenesis remain unknown. We hypothesised that loss of pIgR expression occurs early, and is associated with cell proliferation and poor prognosis. pIgR expression was evaluated by immunohistochemistry in airways of patients with normal mucosa, pre-invasive lesions and invasive lesions, and correlated with clinical outcomes. 16-HBE and A549 cells stably transfected with pIgR were tested for proliferation, apoptosis and cell cycle progression. Immunostaining was strong in normal epithelium, but severely reduced in pre-invasive lesions and most lung cancers. Persistent expression was associated with younger age and adenocarcinoma subtype but not survival. pIgR overexpression significantly reduced A549 and 16-HBE proliferation. Growth inhibition was not due to cell cycle arrest, increased apoptosis or endoplasmic reticulum stress, but we observed altered expression of genes encoding for membrane proteins, including NOTCH3. Interestingly, NOTCH3 expression was inversely correlated with pIgR expression in cell lines and tissues. pIgR expression was lost in most lung cancers and pre-invasive bronchial lesions, suggesting that pIgR downregulation is an early event in lung tumourigenesis. pIgR overexpression in A549 and 16-HBE cells inhibited proliferation. Future investigations are required to determine the mechanisms by which pIgR contributes to cell proliferation.

Down-regulation of the polymeric immunoglobulin receptor in non-small cell lung carcinoma: correlation with dysregulated expression of the transcription factors USF and AP2

The polymeric immunoglobulin receptor (PIGR) mediates transport of IgA and IgM antibodies across mucosal and glandular epithelia. Several studies have utilized immunohistochemistry to demonstrate that PIGR expression varies in different types of lung carcinoma, and is down-regulated during tumor progression. We have previously shown in cultured tumor cell-lines that basal transcription of the PIGR gene is regulated by the transcription factors USF1, USF2 and AP2. To examine the mechanism by which PIGR expression is down-regulated in lung carcinoma, RNA was microdissected from formalin-fixed, paraffin-embedded lung carcinomas (14 adenocarcinomas and 8 squamous cell carcinomas). Levels of PIGR, USF1, USF2 and AP2-alpha mRNA were quantified by real-time reverse transcriptase-polymerase chain reaction and normalized to mRNA for the housekeeping gene GAPDH. PIGR mRNA levels were decreased in adenocarcinomas and squamous cell carcinomas relative to adjacent non-tumor tissue, and were inversely correlated with stage of differentiation. USF1 and USF2 mRNA levels were reduced in adenocarcinomas relative to non-tumor tissue, while AP2-alpha levels were elevated. Multivariate regression analysis demonstrated that reduced USF2 mRNA and increased AP2-alpha mRNA levels were predictive of down-regulated PIGR mRNA expression in the majority of adenocarcinomas and in moderately differentiated squamous cell carcinomas.

Bronchioloalveolar carcinoma: diagnostic pitfalls and immunocytochemical contribution

Because bronchioloalveolar carcinoma (BAC) commonly displays bland cytologic appearance, there is a good potential for misinterpretation. The aim of this study was twofold: one was to identify the most reproducible cytomorphologic features to distinguish BAC from conventional lung adenocarcinoma (CLA) on fine-needle aspiration (FNA), and the other was to investigate the staining characteristics of these two variants of lung carcinoma with P53 tumor suppressor gene immunostain and their potential value in the distinction between the two entities. Cytology records of 13 histologically documented BACs was retrieved: 7 FNA, 3 bronchial washing/bronchial brushing (BW/ BB), and 3 scraping smears of surgical specimens. Two cases had both FNA and BW/BB material. Immunostains for P53 protein, carcinoembryonic antigen (CEA), and Ki67(MIB-1) monoclonal antibodies were performed on 13 BACs (FNA cell blocks and tissue) and on 11 FNA cell blocks of CLA. Cytologically, BAC showed uniform cells with abundant, lacy cytoplasm, and bland, folded nuclei arranged singly, in papillary clusters, and sheets. Immunocytochemically, one BAC and one CLA were technically unacceptable. Of the 12 remaining BAC cases, 10 were reactive with CEA, 9 reactive with Ki67 (> 5%), and 4 reactive with P53. Of the 10 remaining CLAs, 9 were positive with CEA, 9 were reactive with Ki67 (> 5%), and 8 were reactive with P53. We conclude that BAC demonstrates distinctive cytologic features, but difficulty may be encountered with well-differentiated CLA, metastatic adenocarcinoma, and other lesions. Immunocytochemically, CEA and Ki67 do not appear to be discriminate, but P53 may be of value in distinguishing BAC from CLA. Attention to subtle nuclear changes, characteristic grouping, cellular arrangement, and P53 reactivity could enable cytopathologists to accurately diagnose BAC.

Morphology and histogenesis of squamous cell metaplasia of the rat lung after chronic exposure to a pyrolized pitch condensate and/or carbon black, or to combinations of pyrolized pitch condensate, carbon black and irritant gases

Female Wistar rats were exposed to different concentrations of a pyrolized pitch condensate and/or carbon black particles and/or a combination of irritant gases for 18 hours/day, 5 days/week for 10 months, followed by a clean air period of up to 20 months. Bronchiolo-alveolar hyperplasia and squamous metaplasia were important components of the resulting lesions. Squamous metaplasia and associated hyperplasia was investigated by routine histology, scanning and transmission electron microscopy, and by immunohistochemical detection of various cytokeratins (CKs). Intensely CK positive squamous metaplasia lacking a distinct stratum spinosum was distinguishable from squamous metaplasia with a distinct stratum spinosum that reacted weakly CK positive or CK negative. The CK positive type was histologically characterized by narrow intercellular spaces, the weakly CK positive or CK negative type had markedly enlarged intercellular spaces. Differentiated hyperplastic epithelium and the normal lung parenchyma reacted CK negative. In poorly differentiated hyperplasia of the alveolar type associated with squamous metaplasia scattered cells with characteristics of squamous differentiation were detected. Ultrastructurally these cells showed increased amounts of filament bundles and immunohistochemically a positive reaction with the CK antibody. These cells were regarded as precursor stages of squamous metaplasia of the lung periphery in rats.

Radioimmunoimaging of non-small cell lung cancer with 111In- and 99mTc-labeled monoclonal anti-CEA-antibodies

Radiolabeled monoclonal anti-CEA antibodies were used for radioimmunolocalization (RIL) of non-small cell lung cancer; in 30 patients with 111In labeled anti CEA F(ab')2 fragment (BW 431/31) and in 16 with 99mTc-labeled intact MoAb (BW 431/26). RIL results were compared with those of other imaging modalities. Paraffin sections from some patients were also studied immunohistochemically using anti-CEA antibody. Patients with 111In labeled MoAB were imaged twice 1-4 days after injection and for image enhancement pulmonary and liver/spleen subtraction were performed. Twenty-seven of 28 primary tumors were positive and metastases were detected in all patients. The total number of lesions was 78 of which 61 (78%) could be detected by RIL. For verification CT was applied to the study of 46 lesions detected by RIL. We found 6 unknown lesions subsequently verified histologically. Using subtraction techniques we detected 9 lesions in 4 patients, later verified as pulmonary metastases, not detected in unprocessed images. Pleural, mediastinal and pericardial lesions were also better delineated in subtracted images than in unprocessed images. Imaging of non-small cell lung cancer with 99mTc-labeled MoAB was performed twice 4-24 h after injection. RIL results were compared with other imaging methods; CT US, conventional radiography, and immunohistochemistry. Twelve out of 16 patients with suspected or known lung cancer had positive immunoscintigrams; 19 of 25 lesions could be detected by RIL. There were 5 false positive and 2 true negative findings. Immunoperoxidase (IP) stainings of paraffin sections of the tumours from 7 patients were performed using two different anti-CEA antibodies; BW 431/26 and ZCEA1. None of the seven tumors examined by immunohistochemistry were negative when stained by BW 431/26, which was the antibody used for immunoscintigraphy.

Special subtypes of pulmonary adenocarcinomas indicated by different tumor cell HLA-expression and stromal infiltrates. A light, electron microscopic and immunohistologic study

A total of 31 human peripheral adenocarcinomas (AC) of the lung were subclassified by light and electron microscopy according to their phenotypic characteristics. The expression of HLA-A,B,C and HLA-DR on tumor cells, and the degree of subclassified mononuclear cell infiltration were determined using immunohistologic and morphometric methods. The study shows that pulmonary AC can be subdivided in two main types with different properties. The first type is characterized by mucin production comparable to that of bronchial goblet cells. These mucinous AC of type I show nearly no expression of HLA-DR; the tumor volume fraction with HLA-A,B,C expression is greatest in highly differentiated AC I, and decreases significantly with lower grades of differentiation. The AC of type II, possibly originating from the bronchioloalveolar transitional zone, show properties of Clara cells and of type II-pneumocytes by light and electron microscopy. These features include apically located electron-dense granules and lamellar bodies occurring often simultaneously. Both groups of HLA-antigens, HLA-A,B,C and HLA-DR, are homogeneously distributed in a similar phenotypic fashion to Clara cells and pneumocytes II of the normal lung. The significant differences in mononuclear cell infiltration between the two tumor types are possibly induced by the different HLA-DR expression, which have not been seen in AC from other sites. In AC II with homogeneous HLA-DR expression in the tumor epithelium, the numbers of tumor-infiltrating Langerhans cells, and T- and B-lymphocytes are significantly higher than in AC I, possibly indicating better host immunologic defense mechanisms against these tumors.

Surfactant-associated glycoproteins accumulate in alveolar cells and secretions during reparative stage of hyaline membrane disease

Surfactant-associated (SA) glycoproteins are lung-specific proteins produced in the human lung by alveolar type II cells and Clara cells. The distribution of these proteins was studied immunohistochemically in lung tissue obtained postmortem from 12 stillborn fetuses and 49 infants with hyaline membrane disease (HMD). By 21 weeks of gestation, SA glycoproteins were detected in the fetal alveolar epithelium and within Clara cells. The staining increased in intensity and extent with advancing gestational age. Infants with HMD who survived less than 48 hours did not generally exhibit stainable material either within type II cells or secretions, but staining was often noted in Clara cells as well as focally beneath hyaline membranes. In infants surviving more than 48 hours, intense staining of hyaline membranes, alveolar secretions, proliferating alveolar type II cells, and Clara cells was evident. Immunoreactivity was intense in hypertrophic type II cells that formed a continuous alveolar epithelial lining in lungs with bronchopulmonary dysplasia. Included in the population of infants with HMD were 15 infants with pulmonary hypoplasia. The lungs of these infants showed minimal staining for SA glycoproteins regardless of postnatal survival time. The results provide an immunomorphologic basis for defining normal and abnormal lung maturation. They also indicate that enhanced SA glycoprotein production is a sustained response of regenerating and hypertrophic type II cells in premature infants.

Distribution of vitamin B12 R-binder in lung tumors. Implications for cell differentiation

Expression of vitamin B12 R-binder, a specific binding protein for vitamin B12, was studied immunohistochemically in normal lung tissues and 107 lung tumors of various types. In normal tissues, vitamin B12 R-binder (R-binder) expression was restricted to the mucous cells of bronchial or bronchiolar epithelium and submucosal glands as well as to nonciliated bronchiolar (Clara) cells. Among lung carcinomas, 38% of squamous cell carcinomas, 42% of adenocarcinomas and 23% of large cell carcinomas showed positive staining for R-binder whereas small cell carcinomas did not. These findings offer the possibility that a majority of the histologic types of lung carcinoma have common histogenetical characteristics with mucous or Clara cells. Of the bronchial gland tumors, R-binder could be detected in a mucoepidermoid carcinoma but not in adenoid cystic carcinomas. Epithelial components in both pulmonary blastomas and hamartomas showed a reactivity for R-binder, suggesting that these tumors contained components composed of cells with bronchiolar cell differentiation. The immunohistochemical examination of lung tumors, using anti-R-binder antibody, may have some implications in the cell differentiation of lung tumors.

Immunohistochemical localization of pulmonary surfactant apoproteins in various lung tumors. Special reference to nonmucus producing lung adenocarcinomas

Eighty-nine primary lung carcinomas and 23 metastatic lung tumors were immunohistochemically studied for the expression of pulmonary surfactant apoproteins, by using monoclonal (PE-10) and polyclonal antibodies. Surfactant apoprotein was demonstrated in the cytoplasm and/or nuclear inclusion bodies of only primary lung adenocarcinomas (36 of 75 cases), not in any other histologic type of primary lung carcinoma or in metastatic lung tumors. In primary lung adenocarcinoma, although typical type II pneumocyte type adenocarcinoma was not included in the current series, the majority of surfactant apoprotein-positive single cell type tumors were of the Clara cell type, with a single bronchial surface epithelial cell type, according to the light microscopic subclassification of adenocarcinoma cells. The Clara cell type adenocarcinomas could at times be distinguished only with difficulty from adenocarcinoma of type II pneumocyte type. Normal and hyperplastic type II pneumocytes were of course positive for surfactant apoprotein in the cytoplasm. However, none of the positive cells could definitely be identified as Clara cells in non-neoplastic lungs. The findings obtained in this study indicate that surfactant apoprotein is a good marker to distinguish adenocarcinoma of the lung from other histologic types of lung cancer and from neoplasms metastatic to the lung, and that type II pneumocytes and Clara cells, non-neoplastic and neoplastic, are morphologically and functionally closely related and might belong to the same cell lineage.

Altered enzyme expression in propylnitrosamine-induced Syrian hamster lung lesions

Focal proliferative and neoplastic lung lesions induced in Syrian hamsters by dihydroxy-di-n-propylnitrosamine (DHPN) were investigated using a combined histochemical, autoradiographic and electron microscopic approach. Expression of elevated glucose-6-phosphate dehydrogenase (G6PD) and gammaglutamyl-transpeptidase (GGT) activities and levels of immunohistochemically demonstrable glutathione S-transferase placental form (GST-P) were evident in epithelial cells of focal proliferative populations and bronchioloalveolar neoplasms. Binding for the GST-C form, normally only weak, became very pronounced in the stromal elements of DHPN-induced lesions. Increased labelling with tritiated thymidine was associated with increase in morphological atypia within the tumours. Although the enzyme phenotype findings were equivocal the presence of lamellar bodies in some cells of focal proliferative and neoplastic lesions suggested an origin from alveolar type II cells. The present results regarding changed enzyme phenotype in lung lesions suggest important similarities at the biochemical level for the process of neoplasia in the different target organs of DHPN in the hamster and indicate that GST-P may be a useful 'marker' for lung neoplasia.

Pulmonary adenocarcinoma: review of 106 cases and proposed new classification

The gross and microscopic appearances of 106 resected pulmonary adenocarcinomas were reviewed and correlated with postoperative survival. Instead of using an established classification based on histological pattern, the tumours were categorised by cellular morphology and site as either parenchymal adenocarcinoma (67%), bronchial adenocarcinoma (13%), or adenocarcinoma of uncertain origin (20%). Despite their pleomorphic appearance parenchymal adenocarcinomas should be regarded as a single entity, derived from multipotential cells of the distal airway; bronchial adenocarcinomas were generally, but not invariably, associated with short postoperative survival; those tumours that could not be reclassified on histological grounds were large adenocarcinomas consisting mainly of mucus cells. Tumours of this type carry a poor prognosis.

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.

Scar adenocarcinoma of the lung: a light and electron microscopic study

Five well differentiated peripheral adenocarcinomas of the lung were investigated, using light and electron microscopy. Each tumour contained a central nidus of fibrous tissue and fulfilled the criteria for "scar cancer." One tumour also had a focus of lamellated collagenous tissue, suggestive of an old tuberculous granuloma. Electron microscopy showed the features of Clara cells, with characteristic dense bodies in the apical cytoplasm and scattered microvilli on the luminal surface. It was concluded that this variant of scar cancer was a carcinoma of Clara cells, which was sufficiently distinctive in appearance to be recognised on light microscopy alone. It remains uncertain, however, whether the central fibrous area is a desmoplastic response to tumour growth or a pre-existing scar.

Application of monoclonal antibody 44-3A6 in the cytodiagnosis and classification of pulmonary carcinomas

Thirty-five pulmonary carcinomas were studied retrospectively with monoclonal antibody (MCA) 44-3A6 raised against a human adenocarcinoma cell line. The antibody was applied to cytologic smears of bronchial brushings originally stained with the Papanicolau method, and to conventional tissue sections. Ten of 12 adenocarcinomas (ADC) immunostained strongly in sections and smears, as did five of seven large-cell "undifferentiated" carcinomas (LCUC). Eight neuroendocrine carcinomas (NEC) and eight squamous-cell carcinomas (SCC) were negative, except for rare weakly positive foci. We conclude that MCA 44-3A6 can be effectively applied on cytologic smears, and that it could be valuable in the precise classification of pulmonary carcinomas. The immunoreactivity of the ADC and SCC was predictable. Positive immunostaining in some LCUC confirms that these constitute a heterogeneus tumor class that includes cases that are phenotypically ADC despite the absence of obvious glands. Occasional immunostaining in NEC suggests focal exocrine differentiation as previously noted by electron microscopy.

Psammoma bodies and optically clear nuclei in bronchiolo-alveolar cell carcinoma. Diagnosis by fine needle aspiration biopsy with histologic and ultrastructural confirmation

The fine needle aspiration cytology of two cases of bronchiolo-alveolar cell carcinoma of the lung having unusual features is reported. One case demonstrated numerous psammoma bodies in the cytologic smears, whereas the other case showed an abundance of cells with optically clear nuclei. Both peripherally located tumors were resected and confirmed as primary bronchiolo-alveolar cell carcinoma by histologic and ultrastructural examination. We believe this to be the first report describing these unusual features of bronchiolo-alveolar cell carcinoma diagnosed by fine needle aspiration cytology. Presented is a discussion of psammoma bodies and optically clear nuclei seen in primary and metastatic tumors of the lung. This will aid in the diagnosis of these cases.