Mucin-producing adenocarcinoma of the lung, with special reference to goblet cell type adenocarcinoma: immunohistochemical observation and Ki-ras gene mutation

Selection of potential targets for stratifying congenital pulmonary airway malformation patients with molecular imaging: is MUC1 the one?

Currently there is a global lack of consensus about the best treatment for asymptomatic congenital pulmonary airway malformation (CPAM) patients. The somatic KRAS mutations commonly found in adult lung cancer combined with mucinous proliferations are sometimes found in CPAM. For this risk of developing malignancy, 70% of paediatric surgeons perform a resection for asymptomatic CPAM. In order to stratify these patients into high- and low-risk groups for developing malignancy, a minimally invasive diagnostic method is needed, for example targeted molecular imaging. A prerequisite for this technique is a cell membrane bound target. The aim of this study was to review the literature to identify potential targets for molecular imaging in CPAM patients and perform a first step to validate these findings.A systematic search was conducted to identify possible targets in CPAM and adenocarcinoma in situ (AIS) patients. The most interesting targets were evaluated with immunofluorescent staining in adjacent lung tissue, KRAS+ CPAM tissue and KRAS- CPAM tissue.In 185 included studies, 143 possible targets were described, of which 20 targets were upregulated and membrane-bound. Six of them were also upregulated in lung AIS tissue (CEACAM5, E-cadherin, EGFR, ERBB2, ITGA2 and MUC1) and as such of possible interest. Validating studies showed that MUC1 is a potential interesting target.This study provides an extensive overview of all known potential targets in CPAM that might identify those patients at risk for malignancy and conducted the first step towards validation, identifying MUC1 as the most promising target.

Clinicopathological features and prognostic significance of pulmonary adenocarcinoma with signet ring cell components: meta-analysis and SEER analysis

Pulmonary adenocarcinoma is a common type of lung cancer that has been on the rise in recent years. Signet ring cell components (SRCC) can be present in various patterns of pulmonary adenocarcinoma, including papillary, acinar, and solid patterns. "Signet ring cell carcinoma" is a distinct subtype in the 2014 WHO classification of lung neoplasms, subsequent WHO classifications in 2015 and 2021 have deemed signet ring cells as accompanying morphological features with no clinical significance. The prognostic and clinical implications of SRCC in pulmonary adenocarcinoma remain controversial. Therefore, we conducted a meta-analysis to investigate the clinicopathological features and prognostic factors of SRCC in pulmonary adenocarcinoma. We conducted a comprehensive search in PubMed, EMBASE, and Web of Science to identify studies that examined the clinicopathological features and prognostic implications of pulmonary adenocarcinoma with SRCC. We used both fixed- and random-effects models to analyze the data and calculate the pooled hazard ratio (HR) and odds ratio (OR) with 95% confidence intervals (CIs). Additionally, we explored the prognostic significance of SRCC in pulmonary adenocarcinoma using the Surveillance, Epidemiology, and End Results (SEER) database. Our meta-analysis included 29 studies with pulmonary adenocarcinoma and SRCC components. The results showed that pulmonary adenocarcinoma with SRCC was associated with larger tumor size (OR = 1.99; 95% CI, 1.62-2.44, p < 0.001), advanced overall stage (OR = 5.18, 95% CI, 3.28-8.17, p < 0.00001) and lymph node stage (OR = 5.79, 95% CI, 1.96-17.09, p = 0.001), and worse overall survival (OS) compared to those without SRCC (HR = 1.80, 95% CI, 1.50-2.16, p < 0.00001). Analysis using the SEER dataset confirmed these findings. Our meta-analysis provides evidence that pulmonary adenocarcinoma with SRCC is associated with distinct clinicopathological features and a poorer prognosis. These findings have important implications for the management and treatment of patients. However, further studies are needed to validate these findings and explore the significance of SRCC in various subtypes of pulmonary adenocarcinoma.

Goblet cell carcinoid of the rectum: a case report

BACKGROUND

Goblet cell carcinoid (GCC) is a neuroendocrine tumor usually found in the appendix. GCCs exhibit characteristic findings with mixed endocrine-exocrine features such as staining positive for neuroendocrine markers and producing mucin. The primary GCC of the rectum is exceedingly rare.

CASE PRESENTATION

A 77-year-old Japanese male presented with hematochezia. Anal tenderness and a hard mass in the anal canal were found on the digital rectal examination, and colonoscopy was performed. Colonoscopy showed an irregularly shaped mass in the anal canal. Biopsy showed mixed features including adenocarcinoma in situ, well-differentiated adenocarcinoma, and mucinous carcinoma with invasive proliferation. No metastatic lesions were found on the computed tomography scan. Pelvic magnetic resonance imaging scan showed extramural growth of a tumor on the ventral side of the rectum without invasion to the prostate. Laparoscopic abdominoperineal resection was performed. The final diagnosis was well-differentiated adenocarcinoma in the mucosa and goblet cell carcinoid from the submucosa to the adventitia of the rectum. The patient was discharged from the hospital on postoperative day 16. Six months after resection, a computed tomography scan revealed multiple metastatic lesions in the liver. Several chemotherapy regimens were given, and the patient has stable disease 27 months after surgery.

CONCLUSION

We present a patient with rectal GCC with metachronous liver metastases. Since GCC grows intramurally and is biologically aggressive compared to typical carcinoid lesions, the disease is usually diagnosed at an advanced stage. The development of optimal adjuvant chemotherapy is needed for those patients.

Intra-Alveolar Intestinal Epithelium: A Reappraisal of the So-Called Mucinous Goblet-Cell Rich Carcinoma Apropos of Two Cases With Prolonged Follow-up and Literature Review

Primary pulmonary mucin-rich lesions with abundant goblet cells growing within alveolar spaces are either classified as mucinous adenocarcinoma (previously called mucinous bronchioloalveolar carcinoma) or colloid carcinoma. Some of these lesions display a morphologic pattern characterized by paucicellular discontinuous patches of nonatypical colonic type epithelium attached to alveolar walls without evidence of invasion. Immunohistochemically, these epithelial patches express an intestinal immunophenotype (CD20+, CDX-2+, CK7-, TTF-1-). None of the lesions so far reported with these histological and immunohistochemical characteristics have recurred or metastasized. Herein we describe 2 patients with this type of intra-alveolar mucinous lesions who have been meticulously followed-up for 9 and 14 years, respectively, without evidence of disease progression. Based on their histologic appearance, immunoreactivity, and on the presence of occasional CDX-2 expressing cells in terminal airways adjacent to the lesions, we propose alternative interpretations of the mucin-producing epithelium. More important, a separate provisional category for these lesions is suggested that eliminates their force inclusion as adenocarcinomas.

Lung adenocarcinomas: comparison between mice and men

A few human tumor types have been modeled in mice using genetic or chemical tools. The final goal of these efforts is to establish models that mimic not only the location and cellular origin of human cancers but also their genetic aberrations and morphologic appearances. The latter has been neglected by most investigators, and comparative histopathology of human versus mouse cancers is not readily available. This issue is exacerbated by the fact that some human malignancies comprise a whole spectrum of cancer subtypes that differ molecularly and morphologically. Lung cancer is a paradigm that appears not only as non-small cell and small-cell lung cancer but comprises a plethora of subtypes with distinct morphologic features. This review discusses species-specific and common morphological features of non-small cell lung cancer in mice and humans. Potential inconsistencies and the need for refined genetic tools are discussed in the context of a comparative analysis between commonly employed RAS-induced mouse tumors and human lung cancers.

Expression of underglycosylated MUC1 antigen in cancerous and adjacent normal breast tissues

INTRODUCTION

Mucin 1 antigen (MUC1) is a high-molecular-weight transmembrane glycoprotein with an aberrant expression profile in various malignancies, including breast cancer. Its increased overexpression and underglycosylation in breast cancer is associated with tumor invasiveness and metastatic potential. In this study, we took the next step toward establishing MUC1 as a potential diagnostic, prognostic, and therapeutic target by investigating its expression and posttranslational modification (glycosylation/sialylation).

PATIENTS AND METHODS

In these studies we used a breast cancer tissue microarray (TMA) and fresh-frozen multistage breast cancer tissues. We analyzed in detail the expression of normal and underglycosylated/sialated MUC1 by immunohistochemical techniques, real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), and various analytic techniques.

RESULTS

We found that changes in cellular localization as well as in upregulation and/or underglycosylation of MUC1 were associated with higher tumor grade. A key finding in this study was that underglycosylated MUC1 (uMUC1) overexpression and sialation were observed in tissues adjacent to tumor but identified as normal on pathology reports.

CONCLUSIONS

These findings suggest that uMUC1 can indeed be used as an early diagnostic marker and provide additional insights into breast cancer management.

Molecular beacon-based quantitiation of epithelial tumor marker mucin 1

Mucin 1 (Muc1) is a glycoprotein expressed on most epithelial cell surfaces, which has been confirmed as a useful biomarker for the diagnosis of early cancers. In this study, we demonstrate that a quantum dot (QD)-aptamer beacon acts by folding-induced dissociation of a DNA intercalating dye, BOBO-3, in the presence of the target molecules, Muc1. Release of intercalated BOBO-3s from the QD-conjugated aptamers results in a decrease in QD fluorescence resonance energy transfer (FRET)-mediated BOBO-3 emission, allowing for label-free Muc1 detection and quantitation. We attain highly specific and wide-range detection (from 50nM to 20μM) of Muc1, suggesting that our QD-aptamer beacon can be a potential alternative to immuno-based assays for Muc1 detection. The detection methodology is expected to be improved for the early diagnosis of different types of epithelial cancers of large populations.

Rapid real-time electrical detection of proteins using single conducting polymer nanowire-based microfluidic aptasensor

Single polypyrrole (PPy) nanowire-based microfluidic aptasensors were fabricated using a one-step electrochemical deposition method. The successful incorporation of the aptamers into the PPy nanowire was confirmed by fluorescence microscopy image. The microfluidic aptasensor showed responses to IgE protein solutions in the range from 0.01 nM to 100 nM, and demonstrated excellent specificity and sensitivity with faster response and rapid stabilization times (~20 s). At the lowest examined IgE concentration of 0.01 nM, the microfluidic aptasensor still exhibited ~0.32% change in the conductance. The functionality of this aptasensor was able to be regenerated using an acid treatment with no major change in sensitivity. In addition, the detection of cancer biomarker MUC1 was performed using another microfluidic aptasensor, which showed a very low detection limit of 2.66 nM MUC1 compared to commercially available MUC1 diagnosis assay (800 nM).

Frequent ALK rearrangement and TTF-1/p63 co-expression in lung adenocarcinoma with signet-ring cell component

Primary adenocarcinoma with signet-ring cell component (Ad-SRCC) of the lung has been well characterized clinicopathologically and histologically, but their genetics has rarely been investigated. A recent report suggesting an association between Ad-SRCC and EML4-ALK fusion prompted us to undertake a histological, immunohistochemical, and molecular analysis of 10 cases of primary Ad-SRCC identified out of 699 lung adenocarcinomas (1.4%). Most of the Ad-SRCCs showed characteristic architectural as well as cytological features including cohesive clustering of signet-ring cells, a solid/acinar growth pattern, and alveolar filling at the tumor periphery. Diffuse co-expression of TTF-1 and p63 was observed in half of the Ad-SRCCs, and this immunoprofile has not been recognized previously. Four Ad-SRCCs (40%) harbored ALK translocations detected by reverse-transcriptase polymerase chain reaction, fluorescence in situ hybridization, and immunohistochemistry. One new EML4-ALK fusion variant was identified. One ALK-rearranged tumor showed focal squamous differentiation. None of the present Ad-SRCCs had EGFR or KRAS mutations, regardless of ALK status. This study successfully utilized tumor histology alone to identify a subset of adenocarcinomas showing a high rate of ALK translocation. The characteristic histology, immunoprofile, frequent ALK translocation, and total lack of EGFR or KRAS mutations, may suggest that Ad-SRCC forms a histologically/molecularly coherent subgroup of adenocarcinoma.

Aptamer-based detection of epithelial tumor marker mucin 1 with quantum dot-based fluorescence readout

Mucin 1 (MUC1) is a glycoprotein expressed on most epithelial cell surfaces, which has been confirmed as a useful biomarker for the diagnosis of early cancers. In this paper, we report an aptamer-based, quantitative detection protocol for MUC1 using a 3-component DNA hybridization system with quantum dot (QD)-labeling: in the absence of MUC1 peptides, strong fluorescence is observed upon mixing the three specially designed DNA strands (quencher, QD-labeled reporter, and the MUC1 aptamer stem); in the presence of MUC1 peptides, a successive decrease in fluorescence intensity is detected since the MUC1 peptide binds to the aptamer strand in such a way to allow the quencher and fluorescence reporter to be brought into close proximity (which leads to the occurrence of fluorescence resonance energy transfer, FRET, between the quencher and QD). The detection limit for MUC1 with this novel approach is in the nanomolar (nM) level, and a linear response can be established for the approximate range found in blood serum. This study also provided further insight into the aptamer/analyte binding site/mode for MUC1, which augments the possibility of improving this detection methodology for the early diagnosis of different types of epithelial cancers of large populations.

MUC1 plays a role in tumor maintenance in aggressive thyroid carcinomas

BACKGROUND

We recently identified MUC1 as a target driving selection for 1q21 amplification and validated it as an independent marker of aggressive behavior in thyroid cancer (TC). The aims of this study were to determine whether TC cell lines retain MUC1 expression patterns that are seen in primary tumors, assess the role of MUC1 in tumor maintenance, and develop a virally delivered anti-MUC1 RNA interference (RNAi) that is effective in decreasing MUC1 expression in vitro.

METHODS

Fifteen TC cell lines were screened for MUC1 protein expression. Cell lines with varying MUC1 protein levels were treated with anti-MUC1 monoclonal antibody to assess cell viability. A recombinant retroviral short hairpin RNAi delivery system against MUC1 was developed. Efficacy and optimal dosing of short hairpin RNA against MUC1 was determined.

RESULTS

MUC1 expression patterns in TC cell lines were found to be similar to that seen in primary tumors. Treatment with anti-MUC1 antibody resulted in a significant decrease in cell viability in MUC1 over-expressing cell lines. MUC1-779 RNAi construct showed excellent infection efficiency and reproducible silencing.

CONCLUSION

These data offer functional evidence that implicates MUC1 over-expression as a key molecular event in the pathogenesis of aggressive TC. Retrovirally delivered anti-MUC1 RNAi is effective in silencing MUC1 and merits further investigation to establish therapeutic efficacy and safety in anticipation of potential clinical application.

Genetic alterations in cancer knowledge system: analysis of gene mutations in mouse and human liver and lung tumors

Mutational incidence and spectra for genes examined in both human and mouse lung and liver tumors were analyzed using the National Institute of Environmental Health Sciences (NIEHS) Genetic Alterations in Cancer (GAC) knowledge system. GAC is a publicly available, web-based system for evaluating data obtained from peer-reviewed studies of genetic changes in tumors associated with exposure to chemical, physical, or biological agents, as well as spontaneous tumors. In mice, mutations in Kras2 and Hras-1 were the most common events reported for lung and liver tumors, respectively, whether chemically induced or spontaneous. There was a significant difference in Kras2 mutation incidence for spontaneous versus induced mouse lung tumors and in Hras-1 mutation incidence and spectrum for spontaneous versus induced mouse liver tumors. The major gene changes reported for human lung and liver tumors were in KRAS2 (lung only) and TP53. The KRAS2 mutation incidence was similar for spontaneous and asbestos-induced human lung tumors, while the TP53 mutation incidence differed significantly. Aflatoxin B1, hepatitis B virus, hepatitis C virus, and vinyl chloride all caused TP53 mutations in human liver tumors, but the mutation spectrum for each agent differed. The incidence of KRAS2 mutations in human compared to mouse lung tumors differed significantly, as did the incidence of Hras and p53 gene mutations in human compared to mouse liver tumors. Differences observed in the mutation spectra for agent-induced compared to spontaneous tumors and similarities in spectra for structurally similar agents support the concept that mutation spectra can serve as a "fingerprint" of exposure based on chemical structure.

Mucin-producing adenocarcinoma of the lung: thin-section computed tomography findings in 48 patients and their effect on prognosis

OBJECTIVE

To determine the prognostic value of thin-section computed tomography (CT) findings in patients with mucin-producing adenocarcinoma (MPA) of the lung.

METHODS

The study included 48 patients with pathologically proven MPA who had thin-section CT before treatment. The CT findings were correlated with the histopathologic findings and with disease-free survival on follow-up in all patients.

RESULTS

Computed tomography findings identified in patients with MPA of the lung included an air bronchogram (n = 37, 77.1%), areas of ground-glass attenuation (n = 36, 75.0%), areas of air-space consolidation (n = 36, 75.0%), interlobular septal thickening (n = 33, 68.8%), bubble-like lucencies (n = 23, 47.9%), centrilobular nodules (n = 22, 45.8%), and mucus filling of airways (n = 19, 39.6%). Twenty-two (45.8%) of the 48 patients had intrapulmonary metastases. Centrilobular nodules (odds ratio [OR] = 6.7, 95% confidence interval: 1.1-41.4; P < 0.05) and mucus filling of airways (OR = 14.4, 95% 95% confidence interval: 2.0-102.7; P < 0.01) on thin-section CT were independently associated with an increased likelihood of intrapulmonary metastases. The 5-year disease-free survival rates were 67.9% and 38.4% for patients without and with intrapulmonary metastases, respectively (P < 0.05). The presence of centrilobular nodules (relative risk = 10.5, 95% confidence interval: 1.8-59.3; P < 0.01) on thin-section CT was an independent predictor of poor prognosis.

CONCLUSION

Centrilobular nodules on CT are associated with a higher prevalence of intrapulmonary metastases and a poor prognosis in patients with MPA of the lung.

Pulmonary intestinal-type adenocarcinoma does not show enteric differentiation by immunohistochemical study

Six cases of an unusual variant of primary pulmonary adenocarcinoma resembling colorectal and sinonasal adenocarcinoma are presented. Pulmonary intestinal-type adenocarcinoma occurs in elderly Caucasians and is associated with a histology characteristic of colorectal/enteric adenocarcinoma: a garland-like architecture with a 'gland in gland' periphery, central 'dirty' necrosis, and elongated stratified columnar cells, lacking significant goblet or signet ring differentiation. While a resemblance to intestinal adenocarcinoma by light microscopy is present, immunohistochemical studies comparing these carcinomas with metastatic colorectal adenocarcinoma clearly show a respiratory phenotype with the neoplastic cells expressing thyroid transcription factor-1 and cytokeratin 7 to the exclusion of cytokeratin 20, and failing to express CDX-2. Stains for a variety of epithelial mucins (MUC1, MUC2, MUC5AC) also support this observation. The differential diagnosis with other pulmonary adenocarcinomas, especially those with mucinous differentiation, is discussed.

Primary Mucinous (So-called Colloid) Carcinomas of the Lung

Herein we describe the clinicopathologic and immunohistochemical features of 13 primary mucinous (colloid) carcinomas (MCs) of the lung, an uncommon and controversial tumor. The patients, 7 males and 6 females, ranged in age from 50 to 79 years (mean, 64.5 years). All the tumors presented as a peripheral solitary nodule with gelatinous cut-surface and well circumscribed but lacking a complete fibrous wall. The size ranged from 1 to 5.5 cm. Microscopically, they consisted of neoplastic elements floating in large mucin pools and focally lining the alveolar spaces. Eleven cases were predominantly composed of tall, columnar goblet cells (goblet cell-type MC), while 2 consisted of signet-ring tumor cells (signet-ring cell-type MC). Five tumors were incidentally discovered by chest radiographs, while the others were symptomatic. All patients underwent complete surgical resection (six lobectomies and seven wedge resections). Postoperative chemotherapy was performed in 3 cases. Overall, the median follow-up was 26 months (mean 33 months; range 9-95 months). All patients with goblet cell-type MC were alive and well, while the 2 patients with signet-ring cell-type MC died of disease. Immunohistochemically, all the 11 goblet cell-type MCs were strongly stained with CDX-2 and MUC2, 8 reacted with TTF-1, 6 with cytokeratin 20 (CK20), 9 with cytokeratin 7 (CK7), and 2 with MUC-5AC. Conversely, the two signet-ring cell-type MCs were stained with TTF-1, CK7, and MUC5AC but were negative for CDX-2, MUC2, and CK20. Surfactant apoprotein-A (SP-A) was positive in four goblet cell-type and one signet-ring cell-type MC. When compared with 10 mucinous bronchioloalveolar carcinomas (m-BAC), the latter reacted with CK7, CK20, MUC5AC, TTF-1, SP-A, CDX-2, and MUC2 in 100%, 90%, 100%, 30%, 10%, 0%, and 0% of the cases, respectively. In summary, MC of the lung represents an entity with two distinct clinicopathologic and immunophenotypic variants: 1) the goblet cell-type, presenting a more indolent clinical behavior and frequently co-expressing markers of intestinal and pulmonary differentiation; and 2) the more aggressive signet-ring cell-type, which retains only markers of pulmonary origin. On morphologic and immunohistochemical grounds, MCs are easily distinguishable from m-BAC. Since goblet cell-type MC strongly stains with CDX2, MUC2, and CK20, differential diagnosis with metastatic colorectal carcinoma is very challenging and requires appropriate clinical correlation.

Expression ofN-Acetylglucosaminyltransferase V Is Associated with Prognosis and Histology in Non-Small Cell Lung Cancers

PURPOSE

N-Acetylglucosaminyltransferase V (GnT-V), a key enzyme in the formation of branching of asparagine-linked oligosaccharides, is strongly linked to tumor invasion and metastasis of colon and breast cancers. However, GnT-V is expressed in many tissues, including normal lung. GnT-V expression has not been examined previously in human lung cancers. The objective of this study is to examine GnT-V expression in non-small cell lung cancers (NSCLCs) and to determine its relationship to biological and clinicopathological characteristics and prognosis.

EXPERIMENTAL DESIGN

GnT-V expression was studied by immunohistochemistry in 217 surgically resected NSCLCs and analyzed statistically in relation to various characteristics.

RESULTS

High GnT-V expression was found in 113 (52.1%) NSCLCs, and low GnT-V expression was found in 104 (47.9%) NSCLCs. Multivariate logistic regression analysis revealed a significant association between low GnT-V expression and squamous cell carcinomas, as compared with nonsquamous cell carcinomas (P = 0.02). Among biological characteristics of tumors, Ki-67 labeling index was higher in tumors with low GnT-V expression than in those with high GnT-V expression, although this difference was not statistically significant (P = 0.09). Patients with tumors having low GnT-V expression had significantly shorter survival time than patients with tumors having high GnT-V expression in 103 patients with pStage I NSCLCs (5-year survival rates, 49% and 86%, respectively; P = 0.0009), as well as in 59 patients with pStage I non-squamous cell carcinomas (5-year survival rates, 54% and 89%, respectively; P = 0.007). Low GnT-V expression was a significant unfavorable prognostic factor in pStage I NSCLCs (hazard ratio, 2.86; P = 0.002) and in pStage I nonsquamous cell carcinomas (hazard ratio, 3.02; P = 0.02). Furthermore, beta1-6 branching of asparagine-linked oligosaccharides, which are products of GnT-V, were increased highly or moderately in 8 of 10 tumors with high GnT-V expression, as judged by leukoagglutinating phytohemagglutinin staining.

CONCLUSIONS

GnT-V expression is associated with histology in NSCLCs. Low GnT-V expression is associated with shorter survival and poor prognosis in pStage I overall NSCLCs and non-squamous cell carcinomas.

In Vivo Targeting of Underglycosylated MUC-1 Tumor Antigen Using a Multimodal Imaging Probe

One of the most difficult challenges of oncology is to improve methods for early tumor detection, which is crucial for the success of cancer therapy and greatly improves the survival rate. Underglycosylated mucin-1 antigen (uMUC-1) is one of the early hallmarks of tumorigenesis and is overexpressed and underglycosylated on almost all human epithelial cell adenocarcinomas as well as in nonepithelial cancer cell lines, as well as in hematological malignancies such as multiple myeloma, and some B-cell non-Hodgkin lymphomas. In this study, we designed, synthesized, and tested a novel multimodal imaging probe specifically recognizing in vivo uMUC-1 antigen in an animal model of human cancer. Furthermore, in vivo magnetic resonance- and near-infrared-imaging experiments on tumor-bearing animals showed specific accumulation of the probe in uMUC-1-positive tumors and virtually no signal in control tumors. We expect that this probe has a potential to greatly aid in screening prospective patients for early cancer detection and in monitoring the efficacy of drug therapy.

K-ras gene point mutation in neogenetic lesions of subpleural fibrotic lesions: either an early genetic event in lung cancer development or a non-specific genetic change during the inflammatory reparative process

In the present study, K-ras mutation was investigated in 156 neogenetic epithelia that appeared in the lesion of subpleural fibrosis in order to elucidate the close relationship of lung cancer development with pulmonary interstitial pneumonia. The neogenetic epithelia were histologically subclassified into six types: (i) ciliated bronchial epithelium (CBE); (ii) squamous metaplastic epithelium (SME); (iii) cuboidal immature epithelium (CIE); (iv) stratified immature epithelium (SIE); (v) mucus cell epithelium (MCE); and (vi) intestinal metaplastic epithelium (IME). K-ras mutation was detected in 9.6% of neogenetic epithelia overall; 21% of CIE, 12% of SIE, 16% of SME, but not in other types of neogenetic epithelia. Immunohistochemically, CIE and SIE frequently expressed surfactant apoprotein and SME was characteristic to carcinoembryonic antigen expression. According to Ki-67 immunostain, CIE, SIE and SME are likely to grow faster than other histological types of epithelia. K-ras mutation was seen exclusively in codon 12 with predominant G to A and G to C substitutions without any G to T transversions, results which are somewhat different to previous studies in lung cancers. The present study clearly demonstrated that K-ras mutation appeared in certain histological types of neogenetic epithelia, but raised the question of whether K-ras mutation in neogenetic epithelia during the inflammatory reparative process might be an early genetic event in lung carcinogenesis.

Primary signet-ring cell carcinoma of the lung: histochemical and immunohistochemical characterization

To establish criteria for differential diagnosis and to clarify the histogenesis of primary signet-ring cell carcinoma (SRCC) of the lung, five cases were studied by mucin-histochemical and immunohistochemical analyses and compared with SRCC of the gastrointestinal tract and mucus-producing adenocarcinoma of the lung. The proportion of signet-ring cell component varied from 10% to 90% in four cases, and the remaining tumor was a pure SRCC. Mucin-histochemistry showed a close similarity between lung SRCC and goblet cell-type or bronchial gland cell-type adenocarcinoma of the lung. Eighty percent of SRCCs showed positive immunoreactions for lactoferrin, a marker of bronchial gland cell differentiation, the results being consistent with the conclusions in previous studies that lung SRCC is closely related to bronchial gland cell-type adenocarcinoma. The incidence of K-ras mutation detected by the restriction fragment length polymorphism method was relatively high in lung SRCC (three of five) and goblet cell-type adenocarcinoma of the lung (four of four). Mucin-histochemistry indicated that lung SRCC has mucin production similar to that of the colon and colorectal-type SRCCs of the stomach but not to that of gastroduodenal-type SRCC of the stomach. Immunohistochemical staining for MUC-1 and MUC-2 glycoproteins showed a distinct difference; lung SRCC was positive for MUC-1 but negative for MUC-2, whereas colon SRCC and colorectal-type gastric SRCC were negative for MUC-1 but positive for MUC-2.Thus, by a combination of mucin-histochemistry and MUC-1 and MUC-2 immunohistochemistry, primary lung SRCC can be distinguished from metastatic lung SRCC originating in the gastrointestinal tract.

Immunohistochemical, ultrastructural and molecular study of well differentiated adenocarcinomas of the lung predominantly composed of goblet cells

In order to clarify the morphological and biological characteristics of well differentiated adenocarcinoma of the lung predominantly composed of goblet cells (WDAG), histopathological examinations, including some molecular biological procedures, were carried out using 42 surgical specimens of primary lung carcinoma which were predominantly (>50% of the total cell population) or totally composed of goblet cells. The subjects included 19 men and 21 women, ranging in age from 41 to 81 (mean 60 years old) with predominantly nodular, peripherally located lesions. Ultrastructural examination revealed characteristic apical microvillous filamentous core rootless (AFCR) in some, but not all, cases. Histologically, these AFCR corresponded well with structures stained by phosphotungstic acid hematoxylin (PTAH). The goblet cells of WDAG were divided into PTAH-positive (26 cases) and -negative (16 cases) groups. The PTAH-positive group had larger tumor size, greater number of intrapulmonary and extrapulmonary metastases and shorter disease-free interval. The immunoexpression of p53 protein (60%) and rate of K-ras point mutation (84%) were also higher in the PTAH-positive group. Therefore the goblet cell population of WDAG, though it may appear morphologically homogeneous under light microscopy, is actually composed of heterogeneous groups of cells with different histopathological characteristics and biological behavior.

Direct identification of each specific mutation in codon 12 and 13 of ci-ki-ras2 by SSCP analysis

We compared the SSCP behaviour of the DNA fragments containing c-ki-ras 2 wild type 12 and 13 codons or each of the 12 possible point mutated sequences in these two codons. We found that a single electrophoresis condition was sufficient to distinguish each specific mutation from the other 11 and from the wild type sequence. This observation makes it possible to identify each specific mutation directly by SSCP without any need for reamplification and sequencing.