[Development and deployment of a standardized pathology report in lung cancer, basing on a data management software: The PELICAN software]. / Développement et mise en place d'un compte rendu standardisé d'anatomopathologie pour les tumeurs pulmonaires à l'aide d'une application de saisie et d'export des données : l'application PELICAN.

INTRODUCTION: PELICAN (« Partager Éfficacement en Laboratoire les Informations des Comptes rendus ANatomopathologiques ¼) is a software which generates standardized reports and, in parallel, allows to automatically create a database that can be used for research purpose. This application has been used in our laboratory since 2014 for central nervous system tumors. The aim of this work was to extend it to another type of tumor, lung cancer. MATERIALS AND METHODS: The content of the pathology reports was previously defined using various standards (Société Française de Pathologie, Institut National du Cancer, WHO Classification 2015, …). A double codification was used with SNOMED and ADICAP codes. The PELICAN application is a Microsoft Excel file containing a software specifically developed for pathology laboratories, written in Visual Basic for Applications and respecting the CDA-R2 standard. RESULTS: After definition of the software specifications, a beta-version was installed in February 2018. After various updates, the 3.19 version was installed in July 2018. Almost all lung cancer surgical pathology reports are now generated with the PELICAN software; a total of 56 reports were validated at the time of writing this manuscript. The medical time for the generation of the report was globally the same or decreased for some pathologists. The secretarial time was greatly reduced. CONCLUSION: The PELICAN software is an easy to use tool that allows to generate standardized reports in pulmonary pathology and to feed a database that can be easily used for statistical purposes.

Survival Impact of Stations of Pathological Lymph Nodes in N2 Non-small Cell Lung Cancer in a French Hospital.

BACKGROUND: The prognosis of lung cancer remains poor; only 20% of patients can undergo surgery. N2 non-small cell lung cancer (NSCLC) is a heterogeneous disease. We conducted a retrospective study to analyze the impact of N2 location on survival. METHODS: This study included 342 NSCLC with N2 involvement between 1988 and 2014. Patient-related data were collected through the CRB biobank and included demographic, therapeutic, and survival data. Survival was analyzed according to Kaplan-Maier method. Cox's regression analysis and analysis of variance (ANOVA) were used to determine factors significantly associated with survival. RESULTS: The population average age was 61.6 years; 82.2% were men, a majority were former smokers (87.1%), and 45.3% had adenocarcinoma. The main prognostic factors were male gender (p = 0.01), number of nodes (p < 0.0001), and tumor size (p < 0.0001). N2 disease had a poor survival (16 months) compared with N0 (32 months) and N1 (21.1 months) disease (p < 0.0001). The patients with involvement of station 4 (survival = 17.8 months) seemed to have a prognosis between those with station 7 (survival = 10.5 months) and N1 (survival = 22.6 months), p = 0.0005. CONCLUSIONS: N2 location has a prognostic impact in surgically NSCLC, and station 4 involvement has a better prognostic than station 7.

Prognostic Value of Exon 19 Versus 21 EGFR Mutations Varies According to Disease Stage in Surgically Resected Non-small Cell Lung Cancer Adenocarcinoma.

BACKGROUND: The prognostic value of exon 19 and 21 EGFR mutations in stage IV non-small cell lung cancer (NSCLC) is well established. OBJECTIVE: We aimed to evaluate the prognostic value of the mutations in surgically resected NSCLC. METHODS: We retrospectively reviewed data from 1798 surgically resected NSCLC adenocarcinomas between 2007 and 2017 in three departments of thoracic surgery (Nancy/Strasbourg, France, and Torino, Italy) for whom mutational status was known. Overall survival (OS) was evaluated using log-rank and Cox proportional hazard models. RESULTS: EGFR exon 19 deletion was observed in 108 patients (55.1%) and exon 21 L858R mutations were observed in 88 patients (44.9%). In stage I, the median OS was not significantly different between exons 19 and 21 (p = 0.54), while, in stage II, the median OS reached 65 months [95% confidence interval (CI) 41.67-88.33] for exon 19 mutations and decreased to 48 months for exon 21 mutations (95% CI 44.21-51.79; p = 0.027). In multivariate analysis, exon 19 deletion remained a favorable prognostic factor [hazard ratio (HR) 0.314, 95% CI 0.098-0.997; p = 0.05]. In stage III, the median OS reached 66 months (95% CI 44.67-87.32) for exon 19 mutations and decreased to 32 months for exon 21 mutations (95% CI 29.86-34.14; p = 0.03). In multivariate analysis, exon 19 deletion remained a significantly favorable prognostic factor (HR 0.165, 95% CI 0.027-0.999; p = 0.05). CONCLUSION: The prognostic value of EGFR exon 19 and 21 mutations appears to be different according to disease stage in surgically resected NSCLC.

Clinicopathological factors associated with sentinel lymph node detection in non-small-cell lung cancer.

BACKGROUND: Mapping of the pulmonary lymphatic system by near-infrared (NIR) fluorescence imaging might not always identify the first lymph node relay. The aim of this study was to determine the clinicopathologic factors allowing the identification of sentinel lymph nodes (SLNs) by NIR fluorescence imaging in thoracic surgery for non-small-cell lung cancer (NSCLC). METHODS: We conducted a retrospective review of 92 patients treated for suspected or confirmed cN0 lung cancer with curative intent who underwent an intraoperative injection of indocyanine green (ICG) either by direct peritumoral injection or by endobronchial injection using electromagnetic navigational bronchoscopy (ENB). After exclusion of patients for technical failure, benign disease and metastasis, we analyzed the clinicopathologic findings of 65 patients treated for localized-stage NSCLC, comparing the group with identification of SLNs (SLN-positive group) with the group without identification of SLNs (SLN-negative group). RESULTS: Forty-eight patients (73.8%) were SLN-positive. Patients with SLN positivity were more frequently female (50%) than the SLN-negative patients were (11.8%) (p = 0.006). The mean value of diffusing capacity for carbon monoxide (DLCO) was lower among the patients in the SLN-negative group (64.7% ± 16.7%) than the SLN-positive group (77.6% ± 17.2%, p < 0.01). The ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FCV) was higher in the SLN-positive group (69.0% vs. 60.8%, p = 0.02). Patients who were SLN-negative were characterized by a severe degree of emphysema (p = 0.003). There was no significant difference in pathologic characteristics. On univariate analyses, age, female sex, DLCO, FEV1/FVC, degree of emphysema, and tumor size were significantly associated with SLN detection. On multivariate analysis, DLCO > 75% (HR = 4.92, 95% CI: 1.27-24.7; p = 0.03) and female sex (HR = 5.55, 95% CI: 1.25-39.33; p = 0.04) were independently associated with SLN detection. CONCLUSIONS: At a time of resurgence in the use of the sentinel lymph node mapping technique in the field of thoracic surgery, this study enabled us to identify, using multivariate analysis, two predictive factors for success: DLCO > 75% and female sex. Larger datasets are needed to confirm our results.

Place of robotic surgery in completion lobectomy after anatomical segmentectomy.

OBJECTIVES: Although segmentectomy is steadily increasing in early-stage non-small-cell lung cancer, recurrence in the ipsilateral lobe is also increasing. Completion lobectomy (CL) is a challenging procedure that has already been described in a few studies using video-assisted thoracic surgery or thoracotomy. In this study, we aimed to show the feasibility and safety of robot-assisted thoracic surgery in cases of CL. METHODS: Among 2073 major resections performed between January 2018 and september 2022 in the Department of Thoracic Surgery at Nancy University Regional Hospital, we retrospectively included patients who underwent CL by robot-assisted thoracic surgery after previous segmentectomy for non-small-cell lung cancer. Data and perioperative results were described and analysed. RESULTS: Seventeen patients underwent CL with a median recurrence time after previous segmentectomy of 18 months [interquartile range (IQR): 12]. Four patients (23.5%) had a pulmonary artery injury that was controlled, and no conversion to open thoracotomy was needed. The operative time was 150 min (IQR: 20), and blood loss was 300 ml (IQR: 150). The median postoperative chest tube duration was 2 days (IQR: 1), and the length of hospital stay was 3 days (IQR: 3), with no postoperative deaths. CONCLUSIONS: Completion lobectomy is a challenging procedure due to severe adhesions surrounding vessels, which potentially could cause higher rate of PA bleeding than conventional surgeries. With experienced team and surgeons, CL with robotic surgery may be reported as a safe and feasible procedure.

Sentinel Lymph Node in Non-Small Cell Lung Cancer: Assessment of Feasibility and Safety by Near-Infrared Fluorescence Imaging and Clinical Consequences.

Occult micrometastases can be missed by routine pathological analysis. Mapping of the pulmonary lymphatic system by near-infrared (NIR) fluorescence imaging can identify the first lymph node relay. This sentinel lymph node (SLN) can be analyzed by immunohistochemistry (IHC), which may increase micrometastasis detection and improve staging. This study analyzed the feasibility and safety of identifying SLNs in thoracic surgery by NIR fluorescence imaging in non-small cell lung cancer (NSCLC). This was a prospective, observational, single-center study. Eighty adult patients with suspected localized stage NSCLC (IA1 to IIA) were included between December 2020 and May 2022. All patients received an intraoperative injection of indocyanine green (ICG) directly in the peri tumoural area or by electromagnetic navigational bronchoscopy (ENB). The SLN was then assessed using an infrared fluorescence camera. SLN was identified in 60 patients (75%). Among them, 36 SLNs associated with a primary lung tumor were analyzed by IHC. Four of them were invaded by micrometastases (11.1%). In the case of pN0 SLN, the rest of the lymphadenectomy was cancer free. The identification of SLNs in thoracic surgery by NIR fluorescence imaging seems to be a feasible technique for improving pathological staging.

Neutrophil-to-lymphocyte ratio is correlated to driver gene mutations in surgically-resected non-small cell lung cancer and its post-operative evolution impacts outcomes.

BACKGROUND: We sought to evaluate prognostic value of neutrophil-to-lymphocyte ratio (NLR) in surgically resected non-small cell lung cancer (NSCLC) and its correlation to oncogenic drivers. We retrospectively reviewed data of patients who underwent anatomic lung resection for NSCLC and whose mutational status was known, from 4 department of thoracic surgery, over the period 2008 to 2019. Primary endpoints were overall survival (OS) and time to recurrence (TTR). Clinical and molecular factors were investigated in the univariate and multivariate analysis for their association with the primary endpoints. RESULTS: 2027 patients were included in the analysis. Correlations between NLR and OS (R2=0.21), NLR and TTR (R2=0.085) were significant (P<0.0001), with corresponding Pearson R of -0.46 (P<0.0001) and -0.292 (P<0.001), respectively. ROC curve analysis defined NLR cut-off value at 4.07. In the univariable analysis, the median OS was 66 months (95% CI: 62.94 - 69.06) in case of pre-operative NLR ≤ 4.07 and 38 months (95% CI: 36.73 - 39.27) in case of pre-operative NLR > 4.07 (P<0.0001), with corresponding 5-y OS of 72% and 29% respectively. Median TTR was associated with pre-operative NLR. Median TTR was 25 months (95% CI: 21.52 - 28.48) in case of pre-operative NLR ≤ 4.07 and 17 months (95% CI: 16.04 - 17.96) in case of pre-operative NLR > 4.07 (P<0.0001), with corresponding 5-years TTR of 18% and 9% respectively. Significant correlations between NLR >4.07 and KRAS (Cramer's V = 0.082, P < 0.0001) and EGFR mutations (Cramer's V = 0.064, P = 0.004) were observed. CONCLUSIONS: Low pre-operative NLR is associated with longer OS in patients with resected NSCLC. Low pre-operative NLR is not associated with longer TTR in multivariate analysis. Correlation between the high NLR and KRAS/EGFR mutations were observed.

What is the appropriate "first lymph node" in the era of segmentectomy for non-small cell lung cancer?

Introduction: The place of segmentectomy in the management of lung cancer is shifting following the inspiring results of the Japanese JCOG0802 trial. I n this study, authors suggested that performing segmentectomy would require in an optimal way an intraoperative confirmation of pN0 tumor with a frozen section. Our objective was to determine whether the proposed technique, i.e. adjacent lymph node analysis, is consistent with the results of our study on sentinel lymph node (SLN) detection using fluorescence. Methods: This is a retrospective, observational, single center study. Eighty-one patients with suspected localized stage NSCLC (IA to IIA) were included between December 2020 and March 2022. All patients received an intra-operative injection of indocyanine green (ICG) directly in the peritumoral area or by electromagnetic navigational bronchoscopy (ENB). The SLN was then assessed by using an infrared fluorescence camera. Results: In our cohort, SLN was identified in 60/81 patients (74.1%). In 15/60 patients with identified SLN (25%), NIR-guided SLN was concordant with the suggestions of JCOG0802 study. A retrospective SLN pathological analysis was performed in 43 patients/60 cases with identified SLN (71.2%), including 37 cases of malignant disease. Occult micro-metastases were found in 4 patients out of 37 SLN analyzed, leading to a 10.8% upstaging with NIR-guided SLN analysis. Dicussion: At the time of segmentectomies, ICG technique allowed the identification of the SLN in a high percent of cases and in some areas usually out of the recommended stations for lymph node dissection.

Pulmonary metastasectomy in renal cell carcinoma: a mainstay of multidisciplinary treatment.

Renal cell carcinoma (RCC) remains a public health issue and seems to be increasing. A significant proportion of RCC patients will develop pulmonary metastasis at some point in their evolution. In this review, we aimed to update the surgical management of pulmonary metastases as well as systemic therapy, including targeted therapies, according to recent data in the literature. We retrospectively reviewed studies evaluating the benefit of pulmonary metastasectomy in RCC patients and evaluating the place of different chemotherapies, targeted therapies and immunotherapies through November 1, 2019. Several retrospective studies have shown the benefit of pulmonary metastasectomy in metastatic RCC (mRCC), most in a situation with only pulmonary metastases. According to the prognostic criteria of the IMDC risk model, the patient is classified into a prognostic group to identify the best systemic treatment. With the development of targeted therapies, the modalities are multiple and may involve tyrosine kinase inhibitors/checkpoint inhibitors and soon vaccine therapy or CAR-T cells. At the local level, in patients who cannot benefit from surgery, stereotactic radiotherapy or radiofrequency has a place to be considered. Although there is a lack of a randomized study, pulmonary metastasectomy appears to be feasible and effective. The place and modalities of systemic therapies in the era of targeted therapies remain to be more clearly defined.

Safety and Feasibility of Thoracic Malignancy Surgery During the COVID-19 Pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has decreased surgical activity, particularly in the field of oncology, because of the suspicion of a higher risk of COVID-19-related severe events. This study aimed to investigate the feasibility and safety of thoracic cancer surgery in the most severely affected European and Canadian regions during the COVID-19 pandemic. METHODS: The study investigators prospectively collected data on surgical procedures for malignant thoracic diseases from January 1 to April 30, 2020. The study included patients from 6 high-volume thoracic surgery departments: Nancy and Strasbourg (France), Freiburg (Germany), Milan and Turin (Italy), and Montreal (Canada). The centers involved in this research are all located in the most severely affected regions of those countries. An assessment of COVID-19-related symptoms, polymerase chain reaction (PCR)-confirmed COVID-19 infection, rates of hospital and intensive care unit admissions, and death was performed for each patient. Every deceased patient was tested for COVID-19 by PCR. RESULTS: In the study period, 731 patients who underwent 734 surgical procedures were included. In the whole cohort, 9 cases (1.2%) of COVID-19 were confirmed by PCR, including 5 in-hospital contaminants. Four patients (0.5%) needed readmission for oxygen requirements. In this subgroup, 2 patients (0.3%) needed intensive care unit and mechanical ventilatory support. The total number of deaths in the whole cohort was 22 (3%). A single death was related to COVID-19 (0.14%). CONCLUSIONS: Maintaining surgical oncologic activity in the era of the COVID-19 pandemic seems safe and feasible, with very low postoperative morbidity or mortality. To continue to offer the best care to patients who do not have COVID-19, reports on other diseases are urgently needed.

Pseudochylothorax: An unusual mode of revelation of pleural metastasis from solid tumor.

INTRODUCTION: Pseudochylothorax is a rare cause of pleural effusion. Sometimes confounded with chylothorax, firm diagnosis relies on analysis of the pleural liquid: exudative liquid (protein >30 g/L, lactate dehydrogenase >200 UI/L) with a high level of cholesterol (usually >200 mg/dL), low level of triglyceride (usually <110 mg/dL), cholesterol total/triglyceride ratio >1, absence of chylomicron, and in some cases the presence of cholesterol crystals. Pseudochylothorax is secondary to tuberculosis and rheumatoid arthritis in nearly 90% of cases. Its oncologic etiologies are mainly represented by malignant hematologic disorders. METHODS: We report the first case of pseudochylothorax whose cause was the pleural metastasis of an extrathoracic solid tumor in a 61-year-old man with a medical history of oropharynx carcinoma. RESULTS: Computed tomography scan disclosed a left partitioned effusion of high abundance, responsible for a passive atelectasis of the left lower lobe and multiple bilateral pulmonary nodules. A drainage tube was inserted to allow the evacuation of serous liquid; biochemical examination revealed an exudative effusion with pseudochylothorax criteria. Because the daily chest drainage output remained greater than 1 L per day, videothoracoscopy pleural biopsies and talc pleurodesis were performed. Histopathologic examination of the pleural biopsies found a pleural localization of oropharynx carcinoma. CONCLUSION: Because its occurrence is probably underestimated, when pseudochylothorax is diagnosed, oncologic causes should be considered.

High DNA damage by benzo[a]pyrene 7,8-diol-9,10-epoxide in bronchial epithelial cells from patients with lung cancer: comparison with lung parenchyma.

In the present study, the level of benzo[a]pyrene 7,8-diol-9,10-epoxide-N(2)-deoxyguanosine (BPDE-N(2)-dG) in normal bronchial epithelial cells from non-cancerous bronchus of 22 lung cancer subjects was evaluated and compared to the lung parenchyma. We found very high formation of BPDE-N(2)-dG adduct in samples corresponding to a pure preparation of bronchial epithelial cells with 4-fold interindividual differences in the DNA adduct levels in the range of 36.5-175.4 BPDE-N(2)-dG adducts/10(8) nucleotides in smokers (mean: 84.7+/-38.4; n = 13) and 3-fold differences in the range of 19.7-62.4 in non-smokers (mean: 37.6+/-22.2; n = 3). DNA isolated from the bronchial tissue consisting of bronchial lining epithelium with adjacent lamina propria showed significantly lower BPDE-N(2)-dG formation (P < 0.001) in the range of 0.4-4.2 BPDE-N(2)-dG adducts/10(8) nucleotides (mean: 1.8+/-0.56; n = 6). This difference is clearly related to the procedure used to prepare the bronchial tissue samples leading to the presence of different types of cells. Eight samples from the normal parenchyma did not show measurable adducts, the other 14 samples showed 50-fold variation (mean: 1.7+/-1.5; range 0.1-5.2 adducts/10(8) nucleotides; n = 14). There were considerably higher adduct levels in pure bronchial epithelial cells than in parenchymal tissue (75.8+/-38.8 vs 0.9+/-1.5 adducts/10(8) nucleotides) (P < 0.0002) BPDE-N(2)-dG adduct concentrate almost exclusively in bronchial epithelial cells. The adduct values obtained in bronchial epithelial cells could be considered as 'critical' for the initiation of human lung cancer. The high formation of BPDE-N(2)-dG adducts in bronchial epithelial cells and investigations showing that the profile of mutations induced by BPDE in these cells is similar to that seen in the p53 gene isolated from human lung tumors implicates benzo[a]pyrene as important carcinogen in tobacco-induced lung cancer in human beings.

A combination of smears and cell block preparations provides high diagnostic accuracy for endobronchial ultrasound-guided transbronchial needle aspiration.

Endobronchial ultrasound-guided transbronchial needle aspiration has demonstrated its accuracy in the diagnostic workup of enlarged mediastinal lymph nodes. In addition to conventional smears, the use of liquid-based cytology (LBC) and cell block preparations (CBP) has been introduced more recently. The aim of our study was to determine the performance of each of the different techniques, separately and combined, in terms of diagnostic yield and sensitivity. A total of 290 consecutive patients were included. The pathological examination was based on smear cytology, LBC, and CBP. Adequate sampling was defined by the presence of pathological material or lymphocytes. The global diagnostic yield was 82.7 % and the sensitivity was 89.1 %. The diagnostic yield was 72.8 % for smears, 78.8 % for LBC, and 69.9 % for CBP. The combination of smears with CBP significantly increased diagnostic yield (p = 0.01) and sensitivity (p = 0.006), but not the combination of smears with LBC (yield: p = 0.07; sensitivity: p = 0.13). The combination of the three techniques further increased yield (p = 0.007) and sensitivity (p = 0.006), compared with smears alone. CBP were more sensitive than smears for both diagnoses of carcinoma (p = 0.01) and granulomatous inflammation (p = 0.048). Conversely, LBC was less sensitive than smears for granulomatous inflammation (p = 0.004), but the difference was not significant for carcinoma (p = 0.42). CBP, as a complement to smears, increases diagnostic yield and sensitivity for both diagnoses of carcinoma and granulomatous inflammation. LBC, if used alone, increases the risk of a false-negative result.

Do evolving practices improve survival in operated lung cancer patients? A biobank may answer.

INTRODUCTION: Biobanks may play a pivotal role in lung cancer patients' management, research, and health policy. The Nancy "Centre of Biologic Resources" analyzed the evolving profiles of operated lung cancer patients and their management over 20 years. METHODS: A total of 1259 consecutive patients operated upon from 1988 till 2007 were included. Survival rates were statistically compared before and after 1997. The parameters associated with a significant improvement of survival were determined. RESULTS: After 1997, lung cancer was diagnosed at an earlier stage. For Squamous Cell Lung Cancer (SQCLC), stages IA increased from 5.4 to 19.5% and for Adenocarcinoma (ADC), stage IA increased from 9.9 to 24.7%. More women with stage I ADC were operated upon after 1997 (p = 0.01). More patients with Large Cell Lung Cancer were diagnosed recently. Recent patients received more adjuvant or neo-adjuvant chemotherapy (p < 0.001) and less radiotherapy (stage I SQCLC: p = 0.019, stage I ADC: p < 0.001). A longer overall patients' survival was observed after 1997 (chi test for SQLC and ADC independently p < or = 0.002). Among SQCLC long survivors, those at stage I-II, below 50 years, were more numerous. A longer survival was associated with early stage in ADC patients. Stage was the single constant factor for overall outcome. CONCLUSION: Overall and stage-adjusted survival of operated lung cancer patients has been improved in the last decade due mainly to earlier diagnosis. The generalized use of computed tomography scan, chemotherapy, and a collegial management improved patients' survival.

Evaluation of the spatial diffusion of methylene blue injected in vivo by bronchoscopy into non-small cell lung carcinoma.

BACKGROUND: Due to smoking prevalence and the poor efficiency of current therapy, lung cancer is the leading cause of cancer death in developed countries, and its worldwide incidence is steadily increasing. Gene therapy by direct intratumoral injection of different types of gene constructs through a fiberscope has been suggested and evaluated in a few patients. OBJECTIVE: It was the aim of this study to observe the actual volume of diffusion within a lung tumor using a color marker. METHODS: Using bronchoscopy, just after anesthesia, methylene blue was injected into patient tumors. These patients subsequently underwent surgery for treatment of a non-small cell lung cancer. RESULTS: We observed a diffusion of methylene blue in resected lung tumors with a mean infiltrated versus noninfiltrated tumor volume ratio of 29 +/- 15%. Interestingly, some large tumor areas were not stained. At the cellular level, a preferential diffusion of the dye was observed in the tumor stroma compartment versus the tumor cellular compartment, where basal cells were more frequently and strongly labeled than the other tumor cells. CONCLUSIONS: Since a cancer is cured when most, if not all, cancer cells are killed, the preliminary evaluation of the spatial diffusion of any injected gene construct should be carried out as a first step in any cancer type.

In vivo transglutaminase type 1 expression in normal lung, preinvasive bronchial lesions, and lung cancer.

Transglutaminase type 1 (TGase 1) is a member of a class of enzymes that catalyze the cross-linking of proteins, a characteristic feature of epidermal differentiation and squamous metaplasia. The role of TGase 1 has been extensively studied in epidermis but not in the lung. Using a polyclonal anti-TGase 1 antibody prepared in our laboratory (TGase-lac), TGase 1 expression in normal bronchial epithelium, bronchial preinvasive lesions, and lung cancer was characterized. The specificity of the antibody was confirmed by the presence in squamous differentiated bronchial cells of specific 106-kD and 92-kD bands by Western blotting. In addition, immunohistochemistry displayed a recognized pattern of labeling in both normal and tumor cells beneath the cytoplasmic membrane and within the cytosol. TGase 1 was shown to be expressed by cells from bronchial epithelium and bronchial preinvasive lesions, strongly expressed in most non-small-cell lung cancer tumor cells and in apoptotic bodies, but weakly expressed in small-cell lung cancer. The distribution of TGase 1 mRNA correlated with the immunohistochemical profile. These observations suggest that TGase 1 expression is a normal feature of bronchial epithelium and is linked to the process of squamous differentiation occurring in preinvasive lesions. Its role in lung cancer remains to be clarified.