Monoclonal antibody 123C3, identifying small cell carcinoma phenotype in lung tumours, recognizes mainly, but not exclusively, endocrine and neuron-supporting normal tissues

Tumor immune microenvironment characterization in clear cell renal cell carcinoma identifies prognostic and immunotherapeutically relevant messenger RNA signatures

BACKGROUND

Tumor-infiltrating immune cells have been linked to prognosis and response to immunotherapy; however, the levels of distinct immune cell subsets and the signals that draw them into a tumor, such as the expression of antigen presenting machinery genes, remain poorly characterized. Here, we employ a gene expression-based computational method to profile the infiltration levels of 24 immune cell populations in 19 cancer types.

RESULTS

We compare cancer types using an immune infiltration score and a T cell infiltration score and find that clear cell renal cell carcinoma (ccRCC) is among the highest for both scores. Using immune infiltration profiles as well as transcriptomic and proteomic datasets, we characterize three groups of ccRCC tumors: T cell enriched, heterogeneously infiltrated, and non-infiltrated. We observe that the immunogenicity of ccRCC tumors cannot be explained by mutation load or neo-antigen load, but is highly correlated with MHC class I antigen presenting machinery expression (APM). We explore the prognostic value of distinct T cell subsets and show in two cohorts that Th17 cells and CD8+ T/Treg ratio are associated with improved survival, whereas Th2 cells and Tregs are associated with negative outcomes. Investigation of the association of immune infiltration patterns with the subclonal architecture of tumors shows that both APM and T cell levels are negatively associated with subclone number.

CONCLUSIONS

Our analysis sheds light on the immune infiltration patterns of 19 human cancers and unravels mRNA signatures with prognostic utility and immunotherapeutic biomarker potential in ccRCC.

Neuroendocrine neoplasms of the larynx: Advances in identification, understanding, and management

While 85-90% of laryngeal malignancies prove to be squamous carcinomas, the second most common tumour type found in the laryngeal region will prove to be a member of the family of neuroendocrine tumours. Laryngeal carcinoid tumours have a capacity for metastasis, and so are more aggressive tumours than their light microscopic features might imply--5-year survival rates are in the vicinity of 50%. Laryngeal atypical carcinoid tumours are lesions with a well-recognized capacity for local recurrence as well as metastasis, with a 5-year survival of just under 50%. Laryngeal small cell neuroendocrine carcinomas are particularly aggressive tumours, with a 5-year survival of no more than 5-10%. Laryngeal paragangliomas are lesions without any real capacity for metastasizing. Surgical excision is the mainstay of treatment of carcinoid tumours, atypical carcinoid tumours, and paragangliomas. Small cell neuroendocrine carcinomas are chiefly treated by way of radiation and chemotherapy; the role of adjuvant therapy in the treatment of atypical carcinoid tumours remains to be established.

Desmoplastic and spindle cell melanomas express protein markers of the neural crest but not of later committed stages of Schwann cell differentiation

BACKGROUND

The rare desmoplastic and spindle cell variants of malignant melanoma exhibit histological and biochemical features suggestive of early Schwann cell differentiation. These features include a spindle-shaped morphology, neurotropism, and the expression of the low affinity nerve growth factor receptor (p75NGFR).

METHODS

We evaluated by immunohistochemistry (using formalin-fixed, paraffin-embedded tissues) nine desmoplastic and three spindle cell melanomas for the expression of peripherin, p75NGFR, neural cell adhesion molecule (CD56/N-CAM), and growth-associated phosphoprotein-43 (GAP-43). Peripherin is expressed in the neural crest and in neurons, but not in cells committed to the Schwann cell lineage. p75NGFR and CD56/N-CAM also are expressed in early neural crest cells, but persist in unmyelinated and early premyelinating Schwann cells. GAP-43 is expressed in unmyelinated Schwann cells, but is downregulated in the later premyelinating to promyelinating stages of cells committed to the Schwann cell lineage.

RESULTS

Peripherin was expressed in 7/12 (58%), p75NGFR in 4/12 (33%), and CD56/N-CAM in 6/12 (50%) of the desmoplastic and spindle cell melanomas. GAP-43 was not expressed (0%) in any of the 12 melanomas (chi2, p = 0.05).

CONCLUSIONS

Desmoplastic and spindle cell melanomas express protein markers common to cells of the neural crest and to neurons similar to the immunophenotype previously reported for epithelioid cell melanomas. The expression of peripherin and the lack of expression of GAP-43 further define that these rare subtypes of melanoma do not recapitulate the later committed stages of Schwann cell differentiation.

Atypical cells in human cutaneous re-excision scars for melanoma express p75NGFR, C56/N-CAM and GAP-43: evidence of early Schwann cell differentiation

BACKGROUND

A common problem in the routine examination of melanoma re-excision scars occurs when a few or rare mildly atypical cells are present within the scar, raising the question of residual disease. Little is known about the derivation of these cells. Because the normal cutaneous wound-healing process is reparative, we hypothesized that these atypical cells may be reactive proliferating Schwann cell precursors.

METHODS

The expression of the Schwann cell differentiation markers p75NGFR, CD56/N-CAM and GAP-43 was examined by immunohistochemistry in scars of wide local re-excisions for melanoma and non-melanoma tumors. Expression of S100, gp100 (with HMB45) and MART1 was also analyzed by immunohistochemistry.

RESULTS

All melanoma and non-melanoma re-excision specimens contained mildly atypical, spindled or epithelioid cells within the scar. They varied in number from case to case and expressed S100, p75NGFR, CD56/N-CAM or GAP-43 but not gp100 (with HMB45) or MART1. Rare epithelioid non-melanoma cells within the superficial dermis expressed MART-1.

CONCLUSIONS

Atypical cells are present in re-excision scars from melanoma and non-melanoma cases. They demonstrate early Schwann cell differentiation and appear to proliferate during the scarring process. The use of anti-MART-1 alone in the examination of melanoma re-excisions specimens may be inadequate as it may label rare, superficially located, non-melanoma cells within the scar.

NCAM (neural cell adhesion molecules) expression in malignant mesotheliomas

Neural cell adhesion molecules (NCAM) are adhesion molecules expressed by neural and neuroendocrine tumors and a few biphasic tumors such as synovialosarcomas and breast phyllode tumors. To investigate NCAM expression in mesotheliomas, we studied 26 cases of epithelioid (n = 12), biphasic (n = 11), and sarcomatoid (n = 3) malignant mesotheliomas (MM), in comparison with normal mesothelium, and 50 primary non-small cell lung carcinomas (NSCLC) (25 adenocarcinomas [ADC] and 25 squamous cell carcinomas [SCC]), using electron microscopy as a gold standard for recognition of MM. NCAM reactivity using 123C3 antibody was compared with that of NE markers such as chromogranin A and synaptophysin. Although normal mesothelium remains negative, NCAM was expressed in 19 of 26 MM (73%) with a membranous staining on frozen or paraffin sections. In 6 of 12 epithelioid MM, the tumor cells expressed NCAM, whereas in 5 cases stromal fibroblasts showed a strong but focal staining. In 11 biphasic MM, 4 presented an NCAM reactivity of both epithelioid and spindle cell components, whereas in 7, only fusiform component was NCAM positive. Two of 3 sarcomatoid MM showed an NCAM expression. Chromogranin expression was never seen, whereas synaptophysin was noticed in 2 cases. No case of NSCLC showed membranous 123C3 staining, whereas 2 ADC weakly expressed synaptophysin. We conclude that NCAM expression in MM is reminiscent of its expression in mesoderm during fetal life and consistent with that reported in other biphasic tumors. These data show that NCAM expression occurs in 73% of MM, highly exceeding that observed in lung cancer.

Divergent cellular differentiation pathways during the invasive stage of cutaneous malignant melanoma progression

Melanocytic nevus cells in the dermis adopt many morphological features of Schwann cells. These differentiation-related changes typically are not observed in melanomas. However, nevus cells do not fully recapitulate a Schwann cell phenotype, because they lack expression of mature myelin-associated proteins. In this study, melanocytic nevi and malignant melanomas were examined by immunohistochemistry for expression of low-affinity nerve growth factor receptor (p75NGFR), neural cell adhesion molecule (CD56/N-CAM), and growth-associated phosphoprotein-43 (GAP-43). These three proteins define the earliest stages of Schwann cell development but are not expressed in myelinated Schwann cells or normal melanocytes. p75NGFR was expressed in 25 of 25 (100%) and CD56/N-CAM and GAP-43 in 23 of 25 (92%) nevi, predominantly in type C nevus cells and nevic corpuscles. Most (84%) of the nevi expressed all three proteins. In primary invasive and metastatic melanoma, expression of each of the three proteins was limited to </=20% of lesions but was not observed in any melanoma in situ (chi(2 )P < 0.0001). None of the melanomas expressed all three proteins (ANOVA P < 0.0001). These data confirm and extend earlier studies by showing that terminal differentiation of melanocytes in the dermis recapitulates some aspects observed in the earliest stages of Schwann cell development and that invasive melanomas follow a divergent pathway. Studying these early differentiation events may help to identify specific defects in the relevant signaling pathways and establish tenable targets for therapy of advanced-stage melanoma.

Neural cell adhesion molecule expression: prognosis in 889 patients with resected non-small cell lung cancer

INTRODUCTION

In search of factors that might predict outcome in patients with resected non-small cell lung cancer (NSCLC), we studied the reactivity of monoclonal antibody 123C3. This marker of neuroendocrine (NE) differentiation is directed against neural cell adhesion molecules (NCAM). Although NCAM can often be demonstrated in small cell lung cancer and carcinoids as a tumor antigen, not many data exist on NCAM in NSCLC.

PATIENTS AND METHODS

From 1983 through 1995, in 889 patients with NSCLC, who underwent pulmonary resection, 123C3 reactivity was tested. NCAM was correlated with tumor histology, p-TNM stage, and 5-year survival. Large cell NE carcinomas were excluded. Monoclonal antibody-1 (MOC-1) was also tested on most specimens.

RESULTS

Reactivity of 123C3 does not correlate with tumor histology, p-TNM stage, or 5-year survival. In addition, MOC-1 reactivity was not significantly related to prognosis.

CONCLUSIONS

Positive reactivity with 123C3, indicating NE differentiation, does not have predictive value in NSCLC. Also, tumor histology or stage did not correlate with 123C3 reactivity. Reactivity of MOC-1 did not contribute to prediction of prognosis. Whether there is more chemosensitivity in NSCLC-NE than in NSCLC without NE differentiation remains an important question that is not addressed by our present study.

Neural cell adhesion molecules (NCAM) and NCAM-PSA expression in neuroendocrine lung tumors

Neural cell adhesion molecules (NCAM) represent specific markers of neuroendocrine (NE) differentiation in lung cancer. Because the polysialic acid form (NCAM-PSA) has reduced adhesion properties, we hypothesized that NCAM-PSA expression could favor metastatic spread. Immunostaining of NCAM and NCAM-PSA were therefore compared in 120 NE lung tumors, including 17 typical carcinoids, 3 atypical carcinoids, 30 large cell NE carcinomas and 70 small cell lung carcinomas, as compared with 25 adenocarcinomas and 25 squamous cell carcinomas. Neural cell adhesion molecules were negative in adenocarcinomas and squamous cell carcinomas but were constantly expressed in all NE tumors from typical carcinoids to small cell lung carcinomas. NCAM-PSA expression was significantly more frequent in high-grade tumors, with 24 of 30 positive cases in large cell NE carcinomas and 65 of 70 positive cases in small cell lung carcinoma, than in carcinoids with 10 of 17 and 2 of 3 positive cases in typical carcinoids and atypical carcinoids, respectively. The neural cell adhesion molecule-polysialic acid form scores of staining were significantly higher in high-grade as compared with low-grade tumors (p = 0.002), and were correlated with nodal spread (p = 0.04) and metastasis (p = 0.016) across histologic classes but not in individual tumor type. We conclude that NCAM-PSA connotes poor differentiation and aggressive clinical behavior in the spectrum of NE lung tumors, but cannot be regarded as a prognostic factor in individual tumor classes.

A review of neuroendocrine neoplasms of the larynx: update on diagnosis and treatment

Neuroendocrine neoplasms of the larynx have been divided into those of epithelial or neural origin. The latter consist of paragangliomas while the epithelial origin group can be divided into the typical and atypical carcinoids and small cell neuroendocrine carcinomata, the latter consisting of the oat cell type, the intermediate cell type and the combined cell type. There are now over 500 cases of neuroendocrine neoplasms of the larynx in the literature. The diagnosis is primarily based on light microscopy, and, in some instances, it may be supported by special histochemical studies. It should be confirmed by immunocytochemical and/or ultrastructural investigation. The different biological behaviour of neuroendocrine neoplasms of the larynx makes a specific diagnosis of paramount importance, since treatment depends on diagnostic accuracy. Typical carcinoid is an extremely rare lesion. It is treated preferably by conservative surgery; elective neck dissection is not necessary because of the lack of lymph node metastases at diagnosis. Chemotherapy and/or radiotherapy have not been effective in the limited number of patients treated thus far. Prognosis is excellent with cure following surgery. Atypical carcinoid is the most frequent non-squamous carcinoma of the larynx. The mainstay of treatment is surgery. Elective neck dissection should be performed because of the high likelihood of cervical lymph node metastases. Primary radiation therapy with adjuvant chemotherapy is not indicated. The survival rate is 48 per cent at five years and 30 per cent at 10 years. Although the larynx is one of its most common extrapulmonary sites, small cell neuroendocrine carcinoma is still a rare tumour. Surgical results for this tumour have been disappointing and is reserved for cases of local relapse with no evidence of metastasis. Chemotherapy and radiotherapy currently appear to offer the least disabling and most effective forms of therapy. The two- and five-year survival rates are 16 per cent and five per cent, respectively. Paraneoplastic syndromes have occasionally been reported in association with carcinoid tumours (typical and atypical) and small cell neuroendocrine carcinoma. There have been also rare reports of an elevated neuropeptide serum level. Paraganglioma is the only laryngeal neuroendocrine neoplasm with a female preponderance (3:1). Confusion with atypical carcinoid has led to incorrect diagnosis and inappropriate classification schemes, erroneously suggesting that laryngeal paraganglioma has the potential for aggressive behaviour. Conservative surgery represents the treatment of choice; elective neck dissection is not necessary, and the prognosis is excellent.

Immunohistologic analysis of gastrointestinal and pulmonary carcinoid tumors

Carcinoid tumors are potentially malignant neoplasms that arise in various body sites, including the lung and gastrointestinal tract. Those that appear cytologically atypical are more likely to behave aggressively than more typical carcinoid tumors. However, in the absence of cytological atypia or large tumor size, it is difficult to predict the biology of an individual tumor, because some lesions metastasize, whereas others do not. This study had four aims: (1) To study the expression pattern of p53, Ki-67, NCAM, and S-100 in carcinoid tumors and to relate these expression patterns to classical histopathologic features and to tumor location. (2) To identify nonhistological markers that might more accurately predict the early behavior of carcinoid tumors. (3) To determine whether sustentacular cells are present in carcinoid tumors arising in tissues derived from different embryological derivatives. (4) To determine the synaptophysin and chromogranin immunoreactivity in neuroendocrine tumors arising in various locations. The immunostaining reactions were quantitatively scored by three observers. Only 3 of the 39 tumors (all histologically atypical) were strongly positive for Ki-67; two of these were also strongly p53 immunoreactive. NCAM immunostaining differed according to the site of origin: 76.5% of foregut lesions, 58% of the midgut lesions, and 20% of hindgut lesions were positive. S-100 immunostaining ranged from 41% in foregut lesions to 50% in both the hindgut- and midgut-derived tumors. S-100-positive sustentacular cells were present in 20.5% of carcinoid tumors. All tumors stained with antibodies against synaptophysin. In contrast, 100% of midgut, 60% of hindgut, and 88% of foregut tumors were chromogranin positive. Carcinoid tumors tend to have low proliferative rates. p53 immunostaining tends to be strongly positive in tumors that are histologically atypical, but it is negative in typical carcinoid tumors arising in the gastrointestinal tract and lungs. Immunostaining reactions with antibodies to NCAM, S-100, and chromogranin differ depending on the site of origin. Synaptophysin stains 100% of carcinoid tumors regardless of their site of origin. In contrast, antibodies to chromogranin fail to stain 40% of hindgut tumors and 12% of foregut carcinoid tumors. S-100-positive sustentacular cells are present in foregut and midgut tumors but not in hindgut tumors.

Utility of 123C3 monoclonal antibody against CD56 (NCAM) for the diagnosis of small cell carcinomas on paraffin sections

CD56 is immunohistochemically detectable in virtually all small cell carcinomas on frozen sections. The authors retrospectively tested the usefulness of the monoclonal antibody 123C3 against CD56 to differentiate pulmonary and extrapulmonary small cell carcinomas from nonneuroendocrine non-small cell carcinomas by paraffin-section immunohistochemistry after antigen retrieval. The study included 70 small cell carcinomas and 344 primary and metastatic nonneuroendocrine carcinomas of various primary sites. The staining results were compared with specific neuroendocrine markers (CD57, Chromogranin A, Synaptophysin). The monoclonal antibody 123C3 diffusely stained most small cell carcinomas with a strong membranous pattern (sensitivity: 0.99). The staining intensity was not diminished in areas with crush artifacts or after decalcification. The neuroendocrine markers had a combined sensitivity of only 0.44 for small cell carcinomas. With regard to nonneuroendocrine carcinomas, the 123C3 antibody stained 7 of 28 ovarian carcinomas, 6 of 30 renal cell carcinomas, 2 of 10 endometrial carcinomas, two of three nonneuroendocrine large cell carcinomas of the lung, 1 of 38 adenocarcinomas, and 4 of 52 squamous cell carcinomas of the lung. Urothelial carcinomas, hepatocellular carcinomas, squamous carcinomas of the head/neck and cervix uteri, as well as adenocarcinomas of the breast, stomach, colon, pancreas, and prostate, showed no immunoreactivity for CD56. The specificities of 123C3 and the combined neuroendocrine markers for small cell carcinomas were 0.94 and 0.95, respectively. The authors conclude that monoclonal antibody 123C3 might be useful for the immunohistochemical differentiation of small cell carcinomas from nonneuroendocrine carcinomas on paraffin sections, especially in small and crushed biopsy specimens.

A comparison of NSP-reticulons with conventional neuroendocrine markers in immunophenotyping of lung cancers

Neuroendocrine-specific protein (NSP)-reticulons are endoplasmic reticulum-associated protein complexes, which have been identified as markers for neuroendocrine differentiation. In this study, the expression of two members of the family of NSP-reticulons, NSP-A and NSP-C, have been investigated in different types of lung cancer and compared with the expression patterns of five conventional neuroendocrine markers, the neural cell adhesion molecule (NCAM), synaptophysin, chromogranin A, Leu-7, and neurofilament proteins. NSP-A and NSP-C antibodies were reactive with most carcinoid tumour and small cell lung carcinoma (SCLC) cases, while atypical carcinoid tumours showed a variable expression. In the total group of neuroendocrine tumours, a high concordance of expression was found between NSP-A and NSP-C, while their expression correlated well with NCAM and synaptophysin positivity. Chromogranin A, Leu-7, and neurofilament proteins were shown to be expressed to a limited extent in these neuroendocrine tumours. In a selected group of non-SCLCs known to exhibit neuroendocrine features, NSP-A expression was detected at much higher frequency than NSP-C. In virtually all NSP-A positive cases, this expression was associated with one or more of the other neuroendocrine markers. NSP-A expression showed a stronger correlation with conventional neuroendocrine markers than NCAM. In detecting neuroendocrine differentiation in non-SCLC, NSP-A is more sensitive than synaptophysin, chromogranin A, Leu-7, and neurofilament proteins. It is concluded that NSP-reticulons are valuable markers in the diagnosis of neuroendocrine differentiation in non-SCLC and should be used in conjunction with NCAM.

Immunoscintigraphy of small-cell lung cancer xenografts with anti neural cell adhesion molecule monoclonal antibody, 123C3: improvement of tumour uptake by internalisation

The efficacy of three murine monoclonal antibodies (MAbs) for immunoscintigraphy of small-cell lung cancer (SCLS) xenografts was studied in a Balb/c nu/nu mouse model. These Mabs, 123C3, 123A8 and MOC191, belong to cluster 1 of anti-SCLC MAbs and bind to the neural cell adhesion molecule (NCAM) with similar affinity. After intraperitoneal injection of these MAbs, labelled with 125I, the highest uptake in tumour tissue was obtained with MAb 123C3. Seven days after the administration of this MAb 13.9% of the injected dose per gram of tumour tissue was retained in the tumour. The corresponding tumour tissue ratios ranged from 3.97 for blood to 31.03 for colon. The imaging results and the tumour uptake were less favourable for the two other MAbs, 123A8 and MOC191 (fractions of injected dose respectively 6.7% and 9.2%), although affinity, biological activity after labelling and uptake in non-tumour tissues were very similar for all three MAbs. These results may be explained by the differences in the interaction between the MAbs and the tumour cells. Mab 123C3 is internalised into tumour cells, whereas both other anti-NCAM Mabs are not. Internalisation into NCI H69 cells was demonstrated in vitro by radioimmunoassay, confocal laser scanning microscopy and electron microscopy. The internalised fraction of MAb 123C3 was 22.3% after 24h, whereas this fraction was only 7.5% for MAb 123A8. Although the internalised radiolabeled Mabs are usually degraded and dehalogenated intracellularly, the retained radioactivity is high. Apparently, intracellular degradation of radiolabelled MAb 123C3 and subsequent secretion of radioactive iodine did not prevent the accumulation of intracellular radioactivity. In conclusion, accumulation and retention of radioactivity in the tumour tissue, due to internalisation of radiolabelled MAbs, may improve the results immunoscintigraphy.

The neural cell adhesion molecule NCAM in multiple myeloma

The Neural Cell Adhesion Molecule NCAM is a membrane glycoprotein and belongs to the immunoglobulin superfamily. It is expressed on neural cells as well as on various neuroendocrine tumors and can be detected in sera of patients with small cell lung cancer. Its role is attributed to tumor invasion and formation of metastases. Malignant plasma cells and a subset of plasma cells from patients with monoclonal gammopathy exhibit surface expression of NCAM whereas normal plasma cells do not express NCAM. Expression as measured by flow cytometry using anti-CD56 antibodies does not seem to correlate with clinical course, however leukemic myelomas and myeloma cell lines tend to loose NCAM surface expression. An isoform of NCAM which is rich in polysialic acids and characteristic for embryonal NCAM (eNCAM) has been shown to be elevated in sera of patients with multiple myeloma using a chemiluminescence immunoassay. Patients with progressive myeloma tend to have high serum NCAM levels above the normal range of 20 U/ml. Analysis of 125 myeloma patients suggest that serum NCAM is a valuable parameter for tumor progression rather than tumor mass. Increase in serum NCAM may be associated with loss of adhesive function.

Radioimmunotherapy of small-cell lung cancer xenografts using 131I-labelled anti-NCAM monoclonal antibody 123C3

We have studied the therapeutic efficacy of 131I-labelled monoclonal antibody 123C3 in human small-cell lung carcinoma xenografts established from the NCI-H69 cell line in nude mice. Several radiation doses were administered intraperitoneally and different treatment schedules were tested. The maximal tolerated dose, 2 x 500 microCi, resulted in complete remission of tumours smaller than 200 mm3 and long-lasting remission (more than 135 days) of the larger tumours. In control experiments, treatment with unlabelled monoclonal antibody 123C3 did not affect the tumour growth rate, while the effect of radiolabelled non-relevant, isotype-matched, monoclonal antibody M6/1 was minor and transient. Regrowth of the tumours occurred in all cases and could not be attributed to loss of neural cell adhesion molecule (NCAM) expression. Tumour recurrence is probably caused by insufficient radiation dosage. Radiation-induced toxicity was monitored by assessment of weight and bone marrow examination. Weight loss was observed in all treatment groups, but the mice regained their initial weight within 14 days, except for the group receiving the highest radiation dose (3 x 600 microCi). In this group all mice died as a result of radiotoxicity. Of the mice injected with 600 microCi radiolabelled control antibody, 50% died within 2 weeks after administration. Apparently the higher uptake of the radiolabelled monoclonal antibody in the tumour reduced systemic radiation toxicity.

A novel antigen defined by monoclonal antibody CR101 is associated with small cell lung carcinoma

Small cell lung carcinoma (SCLC) represents about 25% of all lung cancers. Human SCLC shows neuroendocrine features such as the production of neural peptide hormones, marker enzymes and neurosecretory granules, and the expression of neural cell adhesion molecules (NCAMs). Although SCLC is sensitive to both chemotherapy and radiation, prognosis remains poor due to the appearance of post-treatment chemo- and radioresistant variants. Monoclonal antibodies (MAbs) have been developed that bind to SCLC tumor antigens. We have used similar technology to define another SCLC marker designated gP94/115. The MAb CR101 binds to a highly glycosylated, cell-surface antigen associated with SCLC. In vitro expression of the antigen appears to be restricted to cell lines of SCLC origin. Enzymatic removal of the sugars resolves the antigen into two proteins of 94 and 115 kD by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Fluorescence-activated cell sorting (FACS) analysis confirms the antibody's specificity. These results indicate that CR101 may recognize a novel protein expressed by SCLC.

Differentiation markers for lung-cancer sub-types. A comparative study of their expression in vivo and in vitro

Cell lines representing the major sub-types of lung cancer have proved to be useful tools to study the molecular and cellular biology of these malignancies, provided that they are well established and well characterized. Antibodies directed against constituents of different cellular compartments can detect the type and degree of differentiation in lung cancer and derived cell lines. Antibodies can detect cell-surface adhesion molecules, such as NCAM, cadherins and integrins. NCAM antibodies are able to differentiate between small-cell lung cancer (SCLC) and non-SCLC, both in cell lines and in tumours. In addition, a spectrum of other membrane proteins, expressed in solid tumours, such as epidermal-growth-factor receptor and carcino-embryonic antigen, are retained in cell lines. Cytoplasmic intermediate filament proteins appear to be generally retained in lung-cancer cell lines, their combinations being the same as in solid SCLC, adenocarcinomas and squamous-cell carcinomas. Nuclear expression of lamins is comparable in tumours and in their corresponding cell lines and can be used to differentiate between SCLC and non-SCLC: A-type lamins, which are present in non-SCLC, are absent in most SCLC.

Neural cell adhesion molecule (NCAM) in normal and neoplastic human pituitary tissues: Analysis by immunohistochemistry and in situ hybridization

The expression of the neural cell adhesion molecule (NCAM) in 6 normal human pituitaries and 25 pituitary adenomas was investigated by immunohistochemistry and in situ hybridization. NCAM protein and mRNA were present in all normal and neoplastic human pituitary tissues. There were tumor type-specific differences in the distribution of NCAM in various pituitary adenomas. Growth hormone adenomas and prolactin-producing adenomas usually expressed lower levels of NCAM, compared to null cell and gonadotroph adenomas. Adreno-corticotropic hormone adenomas expressed the highest levels of NCAM mRNA. Six freshly dissociated pituitary adenomas were cultured in serum-free medium for 7 days to analyze the regulation of NCAM mRNA by in situ hybridization. The lower levels of NCAM expression in growth hormone and prolactin adenomas were not present in cells cultured for 7 days in serum-free medium on extracellular matrix. Phorbol 12-myristate 13-acetate (PMA) stimulated NCAM mRNA expression in 5 of 6 tumors. Gonadotropin-releasing hormone and growth hormone-releasing hormone increased NCAM expression in some adenomas. This study demonstrates that there is a variable expression of NCAM in pituitary adenomas and that hypotha-lamic hormones and PMA can regulate NCAM mRNA levels in neoplastic pituitary cells.

Immunohistochemical detection of two small cell lung carcinoma-associated antigens defined by MAbs F12 and 123C3 in bronchoscopy biopsy tissues

We have studied MAbs* for their ability to detect SCLC and differentiate this tumor type from the other lung tumor histotypes in cryostat sections of biopsy specimens taken at bronchoscopy from patients with suspected primary lung tumor disease. MAb F12, specific for the ganglioside fucosyl-GM1, reacted with 58% of the cases with SCLC (n = 19) and with less than 3% of those with non-SCLC (n = 38). MAb 123C3, specifically reactive with NCAM, reacted with 78% of the SCLC cases (n = 23). With this MAb no positive staining was seen in the non-SCLC cases (n = 41). None of the two MAbs reacted with tissue sections without tumor. In combined analysis with MAbs F12 and 123C3, all SCLC cases (n = 15) were positive with either and 47% with both of the MAbs. Our results show that both MAbs F12 and 123C3 are highly specific for SCLC in bronchoscopic biopsy tissue specimens, whereas the sensitivity for this histotype tends to be higher with MAb 123C3 than with F12 (P = 0.14). When used in combination, all SCLC cases could be identified. These MAbs may therefore be valuable as complements to current histopathologic characterization and differentiation of lung cancer.

Characterisation and properties of a small cell lung cancer cell line and xenograft WX322 with marked sensitivity to alpha-interferon

Controversy exists as to whether interferons usefully influence the growth of epithelial carcinomas. A small cell lung carcinoma (SCLC) cell line, WX322, has been derived which is greater than 1000-fold more sensitive to alpha-interferon (IFN) when grown in agar than other reported SCLC cell lines. The WX322 line has been characterised to prove its epithelial origin and its chemosensitivity compared with that of the NCI-H69 small cell line. The WX322 cell line expresses neuroendocrine and epithelial markers and possesses a morphology consistent with SCLC origin. A concentration of 5 IU ml-1 of IFN produced 50% inhibition of colony formation in agar in the WX322 line, whereas a concentration of greater than 10(5) IU ml-1 was required to produce a comparable effect with the NCI-H69 cell line. In contrast, WX322, possessed similar sensitivity to NCI-H69 cells when exposed to a range of cytotoxic agents. Analysis of the cell cycle indicated that IFN increased the percentage of cells in the G0/G1 phase for the WX322 cell line but increased the percentage in S phase for the NCI-H69 line. Growth of the xenograft, from which the cell line was derived, was also inhibited by IFN at doses greater than 10(5) IU/mouse/day. The WX322 cell line whether grown in agar or as a xenograft shows an unusually high sensitivity to IFN and provides an interesting model for studying mechanisms of IFN cytotoxicity to epithelial cells.

Two monoclonal antibodies against small-cell lung cancer show existence of synergism in binding

Murine IgG1 monoclonal antibodies (mAbs), ITK-2 and ITK-3, were generated against a small-cell lung cancer (SCLC) cell line. Enzyme-linked immunosorbent assay using a variety of established cell lines as substrates, immunoperoxidase staining of freshly frozen tissue sections, and fluorescence-activated cell sorter analysis of peripheral blood leukocytes showed that these mAbs recognize a part of the SCLC-associated cluster 1 antigen. In immunoprecipitation studies, both ITK-2 and ITK-3 bound to a 145-kDa glycoprotein of SCLC cell membrane extracts, as did MOC-1 and NKH-1, which both recognize the cluster 1 antigen. However, because the binding of 125I-labeled ITK-2 to SCLC cells was not inhibited by MOC-1 or NKH-1, the binding site of ITK-2 on SCLC cells appeared to be different from that of either MOC-1 or NKH-1. Unexpectedly, binding of 125I-labeled ITK-2 to SCLC cells increased in the presence of ITK-3. This ITK-3-induced increase in ITK-2 binding was due partly to an increase in the number of binding sites for ITK-2 on SCLC cells. Addition of ITK-3 may, therefore, improve the effectiveness of ITK-2-based tumor detection or therapy.

Neural cell adhesion molecule expression, neuroendocrine differentiation and prognosis in lung carcinoma

We investigated the expression of the neural cell adhesion molecule (NCAM) in a series of surgically resected lung carcinomas of various histological subtypes by means of a panel of monoclonal antibodies recognising different N-CAM epitopes. In a subgroup of 56 tumours, the results of immunostaining with MAb 123C3--the antibody studied most extensively in our material--were compared to the ultrastructure, and in 231 radically resected non-small cell carcinomas, with histological tumour type and with clinical follow-up data. N-CAM expression was not limited to neuroendocrine tumours, as assessed ultrastructurally. Non-small cell lung carcinomas positive for MAb 123C3 showed post-operative overall and disease-free survival times significantly shorter than 123C3-negative non-small cell carcinomas.

Neural cell adhesion molecule (NCAM) is the antigen recognized by monoclonal antibodies of similar specificity in small-cell lung carcinoma and neuroblastoma

We describe reagents from 2 workshops which had been identified as recognizing the same or very similar antigens based on their tissue reactivity. Examination of their tissue specificity led us to the conclusion that this was similar to the expression of the neural cell adhesion molecule (NCAM). We also describe the use of a transfection-based assay to show that these reagents do recognize NCAM. 3T3 cells were transfected with a full-length clone of human NCAM. Indirect immunofluorescence studies showed binding of all related antibodies to the transfectants, but not to the control 3T3 cells. In addition, biochemical analysis using certain antibodies in the cluster confirm that they detect NCAM in the transfectants. Our study shows the benefits of using workshops to compare monoclonal antibodies and a molecular approach to define the antigens recognized by such reagents.

Second primary lung cancer: importance of long term follow up

Review of histopathological and clinical data showed that 153 patients at one hospital developed a second primary lung cancer during 1980-6, 10% of all those with lung carcinoma. There were 64 synchronous tumours (interval less than one year) and 89 metachronous tumours (interval over one year). The average interval between metachronous tumours was 6.1 years. The criteria for diagnosing a second primary lung cancer were any of the following: (1) different histological type; (2) different lobe; (3) interval between the two tumours of at least three years. The incidence of second primary tumours increases with survival, and close follow up is required for their early detection.

Expression of the embryonal neural cell adhesion molecule N-CAM in lung carcinoma. Diagnostic usefulness of monoclonal antibody 735 for the distinction between small cell lung cancer and non-small cell lung cancer

Paraffin sections of 19 surgically resected small cell lung carcinomas (SCLC), 33 non-small cell lung carcinomas (NSCLC) of various types, and four bronchial carcinoids were immunostained with monoclonal antibodies (MoAbs) 735 and anti-Leu 7, both recognizing some sugar epitopes present on the neural cell adhesion molecule N-CAM. With MoAb 735, all SCLC were stained focally or diffusely, and one carcinoid was stained focally. Only three of the 33 NSCLC were faintly and focally positive with MoAb 735; these three tumours showed relatively small tumour cells and small, oval nuclei. Anti-Leu 7 stained all the carcinoids, only eight SCLC, sometimes focally, and eight NSCLC. MoAb 735 was thus superior to anti-Leu 7 in distinguishing between SCLC and NSCLE. Since MoAb 735 stained all SCLC strongly and is applicable on paraffin sections, it provides a well-needed addition to the immunomarkers used in the diagnostic distinction of SCLC and NSCLC.

Clinical applications of monoclonal antibodies against ovarian cancer-associated antigens

Monoclonal antibodies (McAbs), reactive with tumour-associated antigens (TAAs) present on tumour cells, appear to offer new possibilities in the diagnosis and treatment of cancer (Table I). In addition to these prospects for clinical application, monoclonal antibodies also serve as useful instruments in basic cancer research. The hybridoma technology initiated by Köhler and Milstein in 1975, underwent a very rapid development and has now shown its potential in the field of oncology. This technique made it possible to produce very large quantities of homogeneous antibodies of a stable quality. These McAbs often recognize only one antigenic determinant, or epitope, of cell surface and other molecules. This high specificity is essential for in vivo applications, especially in therapeutic immunotargeting. A central question is whether the antibodies can reach and identify those antigens on ovarian tumour cells that are not shared with normal tissues. Various antibodies have been described in the field of gynaecological oncology, which are assumed to be capable of recognizing such ovarian tumour-related antigens. These McAbs, single or in combination, are capable of showing, unambiguously, the presence of various tumour-associated antigens on ovarian carcinoma cells either in tissue or, when antigen shedding occurs, in blood. However, these McAbs may also react with tumour-associated antigens present on endometrial, cervical, colorectal, breast or other carcinoma cells. The original immunogens used to generate these McAbs differ as to their origin: ovarian cancer cells, breast cancer cells, human milk-fat preparations, trophoblastic cells, endometrial cancer cells have been used as well as osteogenic sarcoma cells, epidermoid carcinoma cells and small-cell lung cancer, colorectal, pancreatic and laryngeal carcinoma cells. The histological distribution patterns of the antigens recognized by these McAbs vary widely: cross-reactions with normal tissue and with carcinomas different from those used as immunogen are frequently seen.