Widespread molecular alterations present in stage I non-small cell lung carcinoma fail to predict tumor recurrence

Stage I non-small cell carcinoma (NSCLC) of the lung is typically treated with surgery alone, but with a 30 to 40% recurrence rate. Prognostic factors to stratify these patients into high- and low-risk groups would be of significant clinical value, but published data are conflicting. We studied 39 Stage I NSCLC treated with resection alone, followed for a minimum of 5 years, and divided into recurrent (RC) and non-recurrent (NRC) groups (n = 12 and 27, respectively). Allelic imbalance (loss of heterozygosity, LOH) involving genomic regions containing L-myc (1p32), hOGG1 (3p26), APC/MCC (5q21), c-fms (5q33.3), p53 (17p13), and DCC (18q21), and point mutational change in K-ras-2 (12p12) were studied by PCR-based microsatellite analysis and DNA sequencing. Mutations in k-ras-2 were seen in 25% and 19% of RC and NRC tumors, respectively, most frequently in adenocarcinomas. LOH in the RC and NRC respectively were 50% and 37% for L-myc, 60% and 33% for hOGG1, 60% and 50% for APC, 38% and 35% for c-fms, 78% and 75% for p53, and 17% and 45% for DCC. No statistical significance was seen comparing any of the allelic alterations with recurrence. LOH for hOGG1 and L-myc were more commonly seen in squamous cell carcinomas. Stage I NSCLC are genetically heterogeneous with respect to mutation acquisition. The approach of investigating a panel of genes for alterations can be applied to any given tumor type, and provides information on patterns of mutations/LOH that can help us better understand the molecular biology of tumorigenesis.

Intrathymic inoculation of donor bone marrow induces long-term acceptance of lung allografts

BACKGROUND

We investigated whether intrathymic inoculation of donor bone marrow at the time of transplantation induced long-term acceptance of lung allografts.

METHODS

Four- to-six-week-old August Copenhagen Irish (ACI) and Wistar Furth (WF) rats were used as donors and recipients, respectively. After being inoculated intrathymically with either donor-specific (ACI) or third-party (F344) bone marrow (2.0 x 10(7) cells/lobe), the recipient (WF) animal received a left lung transplant from an ACI donor. A short course of tacrolimus (1 mg/kg per day for 5 days) was administered. Animals were sacrificed at timed intervals after transplantation, and rejection was graded on a scale of 0 (none) to 4 (severe).

RESULTS

At 28 days, animals receiving donor-specific bone marrow have lower (p < 0.01) median rejection grade (MRG = 0.25; n = 6) than those receiving third-party bone marrow (MRG = 3; n = 6) and controls (no bone marrow; MRG = 2.5; n = 6). Animals receiving intrathymic donor bone marrow accepted lung allografts up to 380 days with minimal rejection (MRG = 2; n = 6). Long-term lung recipients also accepted a challenging donor-specific heart graft (n = 4) for more than 150 days. In mixed lymphocyte reaction assays, T lymphocytes of WF recipients that had received intrathymic bone marrow (from ACI donor) exhibited low response (similar to self antigens) to donor (ACI) cells, but reacted strongly (five times higher) to third-party (F344) cells.

CONCLUSIONS

Intrathymic inoculation of donor bone marrow at the time of transplantation along with a short course of tacrolimus induces long-term acceptance of lung allografts in rats. This simple approach of tolerance induction may have clinical application.

Idiopathic bronchiolocentric interstitial pneumonia

The authors report 10 patients with a distinctive idiopathic bronchiolocentric interstitial pneumonia having some histologic similarities to hypersensitivity pneumonitis. Bronchiolocentric interstitial pneumonia has a marked predilection for women (80%) and occurs in middle age (40-50 years). Chest radiographs and pulmonary function tests show interstitial and restrictive lung disease, while the histologic appearance is that of a centrilobular inflammatory process with small airway fibrosis and inflammation that radiates into the interstitium of the distal acinus in a patchy fashion. Granulomas are not identified. At a mean followup of approximately 4 years in nine patients, 33% of patients were dead of disease and 56% had persistent or progressive disease suggesting a more aggressive course than hypersensitivity pneumonitis and nonspecific interstitial pneumonia, the two major disease processes in the differential diagnosis. Whether Bronchiolocentric interstitial pneumonia is a unique entity or not, the pattern of bronchiocentric injury to the lung in the absence of known causes and its clinical presentation as interstitial lung disease, warrants further investigation of this unusual interstitial process.

Small-cell neuroendocrine carcinoma displays unique profiles of tumor-suppressor gene loss in relationship to the primary site of formation

Small-cell neuroendocrine carcinoma (SCNC) is a well characterized malignancy with distinctive cellular morphology and aggressive biologic behavior most frequently encountered in the lung but also noted for origin from other sites. The basis for this difference in incidence and the impact of primary site location on the molecular pathogenesis of the neoplasm is not well understood. To address this issue and to identify reliable molecular markers of potential diagnostic value for primary site localization of this tumor, we have compared the genetic profile of cancer-related gene damage of SCNC arising from a variety of organ sites. The analysis involved microdissected paraffin-embedded formalin fixed specimens of SCNC. Tumors were organized into 3 groups: lung (n = 18), head and neck region (n = 5), and gastrointestinal tract (n = 5). Genotyping evaluated allelic imbalance (loss of heterozygosity) involving genomic regions containing p53 (17p13), L-myc (1p34), OGG1 (3p26), MCC/APC (5q21), p16 (9p21), PTEN (10q23), and point mutational change in K-ras-2 (12p12) using polymerase chain reaction-based microsatellite analysis and DNA sequencing. Distinct genotypic profiles of allelic imbalance using this panel was seen for each group of SCNC enabling primary site determination to be suggested based on genotypic profiling of microdissected tissue samples. Despite similarity in histologic appearance, our study suggests that SCNC have a unique pattern of acquired allelic damage that is determined in part by primary site of tumor development. These attributes can be effectively used for primary localization of metastatic SCNC, thereby assisting in the diagnosis and classification of this neoplasm.

Comparison of accumulated allele loss between primary tumor and lymph node metastasis in stage II non-small cell lung carcinoma: implications for the timing of lymph node metastasis and prognostic value

Although the Tumor-Node-Metastasis staging of non-small cell lung carcinoma (NSCLC) is the most effective predictor of survival, the clinical outcome of patients at each stage is variable on an individual case basis. We tested the value of incorporating information about the tumor heterogeneity of NSCLC into microsatellite allelotyping in a cohort of 48 node-positive stage II patients (T1N1M0 and T2N1M0). Microsatellite allelotyping involved microdissection of the invasive component of primary tumor and lymph node metastasis at multiple target sites followed by loss of heterozygosity (LOH) analysis at specific regions on chromosomes 1p, 3p, 5q, 7q, 8q, 9p, 10q, 17p, and 18q using 16 markers. All microsatellites manifested LOH ranging from 44 to 76% in primary tumor and showed various degree of heterogeneity between primary tumor and lymph node metastasis. LOH on 3p and 5q in the lymph node metastases was associated significantly with shortened survival of the patients (P = 0.033 and 0.004, respectively), whereas no single LOH in the primary tumors showed association with prognosis. For the analysis of the accumulated load of allele loss, fractional allele loss (FAL) was calculated for each sample. The maximal FAL of lymph node metastasis was significantly lower than that of primary tumor (P = 0.0015), possibly reflecting the early lymphatic spread. High maximal FAL of lymph node metastasis was significantly correlated with an adverse outcome (P = 0.012), whereas maximal FAL of primary tumor did not show any prognostic significance (P = 0.552). A composite mutational profile for each patient based on the allelotyping of the primary tumor and lymph node deposits may make a significant contribution to a more accurate prognosis of stage II NSCLC.

Molecular pathogenesis of pulmonary carcinosarcoma as determined by microdissection-based allelotyping

Pulmonary carcinosarcoma is a rare, biphasic tumor composed of malignant epithelial and mesenchymal elements. Its histogenesis is controversial in light of the presence of divergent cell lineages and the clonal nature of malignancy. To address these issues, we performed an extensive comparative genotypic analysis using microdissection to secure representative mesenchymal and epithelial components from each of six cases of pulmonary carcinosarcoma. Loss of heterozygosity was analyzed with a panel of 12 polymorphic microsatellite markers designed to indicate allelic loss and situated in proximity to known tumor suppressor genes located on 1p, 3p, 5q, 9p, 10q, and 17p. In accordance with the relatively greater biologic aggressiveness of this tumor type, both the epithelial and mesenchymal components showed extensive allelic loss, most notably for 3p, 5q, and 17p. More importantly, we found overall equivalent patterns of acquired allelic loss between the two components on an individual case basis, strongly supporting the monoclonal origin of these neoplasms. Minor differences in the allelic fingerprint between the two cell lineages could be explained by progressive accumulation of allelic loss alterations that appear to occur more frequently in the mesenchymal component of the tumor. The data support the efficacy of microdissection-based allelic fingerprinting to delineate the relationship between different morphologic components of a single neoplasm.

In vivo expression of p53 and Bcl-2 and their role in programmed cell death in premalignant and malignant lung lesions

Forty-four specimens of non-malignant and malignant human lung tissue, taken from patients with non-small cell lung cancer (NSCLC), were examined for the expression of wild-type p53, mutant p53, and bcl-2 and the occurrence of programmed cell death (apoptosis). Wild-type p53 expression peaked in peritumoral and metaplastic samples, whereas mutant p53, bcl-2 and apoptosis were first detected in metaplasia and increased with progression to carcinoma. Bcl-2 positive samples had lower levels of apoptosis than bcl-2 negative samples and was independent of wild-type or mutant p53 expression. These results suggest that the over-expression of wild-type p53 may be an early cellular response to an alteration in normal cellular homeostasis. The ensuing increase in apoptosis appears to be relatively independent of mutant or wild-type p53 expression, but does not occur in cells expressing bcl-2.

Absence of jaagsiekte sheep retrovirus DNA and RNA in bronchioloalveolar and conventional human pulmonary adenocarcinoma by PCR and RT-PCR analysis

Bronchioloalveolar adenocarcinoma (BAC) morphologically resembles sheep pulmonary adenomatosis (SPA), a contagious ovine pulmonary adenocarcinoma caused by the jaagsiekte sheep retrovirus (JSRV). Previously, positivity for JSRV by immunostaining, reverse-transcription polymerase chain reaction (RT-PCR), and Western blot was reported in most nonmucinous BACs. Our objective in this study was to analyze additional BAC subtypes and conventional adenocarcinomas (CA) to further substantiate this association. Tumor tissue was microdissected from unstained paraffin sections of 26 cases of formalin-fixed, paraffin-embedded BAC (7 mucinous, 17 nonmucinous, 2 sclerosing) and 29 cases of CA. Positive controls consisted of 2 separate paraffin blocks of known SPA. Primer sequences were derived that were capable of hybridizing to all reported strain variants of both the DNA (endogenous) and RNA (exogenous) forms of JSRV. Each sample was tested using both PCR (DNA) and RT-PCR (RNA). All BAC and CA cases were negative for JSRV. Positive controls yielded PCR products that were sequenced and precisely matched the published prototype stain of JSRV. To control for negative effects of tissue fixation, dilutions of positive control tissue were added to BAC and CA samples. Detection of JSRV was evident at 1:50 dilution. Although the possibility of a viral association with BAC cannot be excluded, this study shows that the association with JSRV is probably very weak, if present at all.

Pulmonary apical cap: a distinctive but poorly recognized lesion in pulmonary surgical pathology

Thirteen cases of pulmonary apical cap (PAC), resected for the exclusion of a clinical diagnosis of lung carcinoma, were reviewed, and their distinctive morphology was described. PAC occurred in older individuals, particularly in the apices of the upper lobes, and by radiographic examination appeared as spiculated subpleural masses ranging from 0.7 to 5.2 cm in diameter. Microscopically, these subpleural scars were pyramid shaped with overlying pleural adhesions and hyaline pleural plaques. They were characterized by a dense basophilic fibrosis of the pulmonary parenchyma with air spaces filled with old, mature collagen and the underlying elastic skeleton contracted in an accordion-like fashion with reduplicated curls of elastic fibers. Scar emphysema was prominent at the periphery of these fibrous nodules. PAC should be recognized for its unique histology because its appearance in the surgical pathology laboratory will likely increase in incidence with the evolution of more sensitive pulmonary radiographic studies. A chronic ischemic etiology is favored.

Pulmonary Langerhans' cell histiocytosis: molecular analysis of clonality

Pulmonary Langerhans' cell histiocytosis (LCH) is a form of Langerhans' cell disease that primarily affects smokers in the third to fifth decade. Extrapulmonary manifestations are rare. Its clinical course is typically characterized by stabilization or regression of bilateral micronodular infiltrates seen on chest radiographs; progression to honeycomb fibrosis is rare. Because the clinical course of pulmonary LCH is distinct from systemic multiorgan LCH, currently thought to be a clonal proliferative disorder, we examined the X-linked polymorphic human androgen receptor assay (HUMARA) locus to assess clonality in female patients with one or more discrete LCH cell nodules in open lung biopsies. Langerhans' cells (LCH cells) were excised from formalin-fixed, paraffin-embedded tissue by microdissection to assure a relatively pure cellular population, and studies for differential methylation patterns at the HUMARA locus were performed. Twenty-four nodules in 13 patients were evaluated. Seven (29%) were clonal and 17 (71%) were nonclonal. Of six cases with multiple discrete nodules, three (50%) showed a nonclonal LCH cell population. In one biopsy with five nodules, two nodules were clonal with one allele inactivated, one nodule was clonal with the other allele inactivated, and two nodules were nonclonal. In contrast to systemic LCH, pulmonary LCH appears to be primarily a reactive process in which nonlethal, nonmalignant clonal evolution of LCH cells may arise in the setting of nonclonal LCH cell hyperplasia. Cigarette smoking may be the stimulus for pulmonary LCH in contrast to other forms of LCH.

Involvement of 2p23 in pulmonary inflammatory pseudotumors

Pulmonary inflammatory pseudotumors (IP) are rare mesenchymal proliferations that have a polymorphic histology and an unpredictable biologic behavior. The histologic spectrum of IP has led to uncertainty as to whether this tumor has a reactive or neoplastic pathogenesis. Reports of extrapulmonary IP have identified clonal chromosomal aberrations involving 2p23 in the region of the ALK gene. Using fluorescence in situ hybridization with a probe flanking the ALK gene at 2p23 and immunostaining for the ALK gene product, we studied formalin-fixed, paraffin-embedded tissues of pulmonary IP and found a subset (33%) with 2p23 aberrations. We suggest that chromosomal rearrangements and ALK immunostaining may be helpful in the diagnosis of a group of pulmonary IP and should be investigated as a potential tool for predicting their future biologic behavior. An association with anaplastic large-cell lymphoma was also observed. HUM PATHOL 32:428-433.

Eosinophilic pneumonia-like areas in idiopathic usual interstitial pneumonia

Usual interstitial pneumonia is the most common idiopathic chronic interstitial pneumonia, characterized by a temporally heterogenous pattern of interstitial injury with interstitial mononuclear infiltrates, septal fibromyxoid nodules, and parenchymal scarring. This report details the presence of focal eosinophilic pneumonia in six cases of usual interstitial pneumonia in the absence of known causes of this reaction. The relationship of eosinophilic infiltrates in usual interstitial pneumonia with regard to pathogenesis, differential diagnosis, and prognosis is discussed.

Nodular amyloidoma and primary pulmonary lymphoma with amyloid production: a differential diagnostic problem

Nodular amyloidomas (NA) of the lung are non-neoplastic inflammatory nodules containing eosinophilic amyloid deposits and a lymphoplasmacytic infiltrate. In some instances, the extensive amyloid deposits may obscure an underlying lymphoproliferative disorder. The histologic and immunohistologic features that discriminate these two differential diagnostic possibilities were studied in this series of six cases of NA and five cases of primary low-grade malignant lymphomas of lung with secondary amyloid deposits (ML). Two of lymphoma cases showed histopathologic and immunophenotypic features of B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma (B-cell CLL/SLL), and three cases were low-grade B-cell lymphoma derived from mucosa associated lymphoid tissue (MALT lymphoma). Key discriminating morphologic features between NA and ML included lymphatic tracking of the cellular infiltrate (3/5 ML; 1/6 NA), pleural infiltration (3/5 ML; 0/6 NA), sheet-like masses of plasma cells (5/5 ML; 0/6 NA) and reactive follicles (4/5 ML; 1/6 NA). Lesional circumscription, vascular and bronchial destruction, lymphoepithelial lesions, and granulomas were not helpful discriminators. Immunohistochemical features indicating a dominant CD20+, CD79a+ B-cell population (5/5 ML; 0/6 NA), light chain restriction (4/5 ML; 0/6 NA), and aberrant antigen expression of CD20/CD43 (2/5 ML; 0/6 NA) were helpful. Amyloid tumors with a reactive lymphoplasmacytic infiltrate can be separated from low-grade malignant lymphomas utilizing both histologic and immunohistochemical features.

The anatomic distribution of acute cellular rejection in the allograft lung

BACKGROUND

Transbronchial lung biopsy (TBLB) is used for routine monitoring and diagnosing of acute cellular rejection (ACR) in the lung allograft, and yet the optimal anatomic site for lung biopsy has not been investigated. We examined our clinical data to clarify the distribution of ACR in the lung allograft monitored by TBLB.

METHODS

A retrospective case-series study was done reviewing the pathology files and slides of TBLB performed on lung allograft recipients. In 73 patients, transbronchial biopsies were taken from more than one lobe.

RESULTS

Identical grades of ACR were seen in 33 of 73 (45%) patients, and a single-grade difference in ACR was noted 34 of 73 (47%) patients. Six cases demonstrated two or more grade differences on biopsies taken from two separate lobes. Among cases with different grades of ACR, the "upper" lobes had a higher grade in 35% (14/40) and the "lower" lobes had a higher grade in 65% (26/40).

CONCLUSIONS

If limitations on the site for transbronchial biopsy exist, biopsies of the lower lobes appear more informative.

Segmental nonanastomotic bronchial stenosis after lung transplantation

BACKGROUND

Nonanastomotic distal bronchial stenosis has been observed in some patients after lung transplantation. We investigated its relationship with acute cellular rejection (ACR), infection, and ischemia.

METHODS

Between January 1994 and December 1997, 246 lung transplantations were performed at our hospital. These cases were retrospectively reviewed and evaluated to identify those patients with nonanastomotic bronchial stenosis.

RESULTS

Six patients had bronchial stenosis within the grafted airway distal to the uninvolved anastomotic site. The average ACR before stenosis was 1.9 compared with 1.6 in a control group. ACR at the time of first recognition of the stenosis ranged from A2 to A3.5, with an average value of A2.9. All 6 patients demonstrated alloreactive airway inflammation before and at the time of stenosis. Four patients had evidence of ischemic damage in the perioperative period.

CONCLUSIONS

Segmental nonanastomotic large airway stenosis after lung transplantation should be assessed separately from anastomotic complications. Although the pathogenesis is unclear, certainly one should consider alloreactive injury, ischemic damage, and infection as individual and coercive causes.

11q13 allelic imbalance discriminates pulmonary carcinoids from tumorlets. A microdissection-based genotyping approach useful in clinical practice

Pulmonary tumorlets are minute neuroendocrine cell proliferations believed to be precursor lesions to pulmonary carcinoids. Little is known of their molecular pathogenesis because of their small size. Using tissue microdissection, we evaluated 11q13 region allelic imbalance in the pathogenesis of pulmonary tumorlet/carcinoid lesions. The int-2 gene was selected because of its chromosomal location at 11q13 in close proximity to MEN1, a tumor suppressor gene frequently mutated in familial forms of neuroendocrine cancer. Three cohorts of patients were studied: subjects with typical carcinoid tumors and coexisting tumorlets (n = 5), typical carcinoids without tumorlets (n = 6), and tumorlets alone without carcinoid lesions (n = 5). A total of 11 carcinoids and 11 tumorlets were microdissected from 4-micrometer-thick histological sections. Genotyping was designed to detect allelic imbalance of the int-2 gene and involved DNA sequencing of two closely spaced deoxynucleotide polymorphisms. Subjects shown to be informative were evaluated for allelic imbalance in tumorlet/carcinoid tissue. Eight of 11 (73%) carcinoids manifested allelic, in contrast to only one of 11 (9%) of tumorlets. Int-2 allelic imbalance was significantly associated with carcinoid tumor formation (P < 0.01). In patients having both carcinoid tumors and tumorlets, the latter showed allelic balance and were thus discordant in genotype with coexisting carcinoid excluding pathogenesis of tumorlets from intramucosal spread from carcinoid tumors. Int-2 allelic imbalance was shown to be an early event in carcinoid tumor formation by virtue of the absence of allelic imbalance for other common cancer-related gene disturbances involving 11p13 (Wilms' tumor), 3p25 (von-Hippel-Lindau), and 17p13 (p53). Demonstration of 11q13 allelic imbalance by microdissection/genotyping may be a useful discriminatory marker for pulmonary neuroendocrine neoplasia.

The significance of bronchus-associated lymphoid tissue in human lung transplantation: is there an association with acute and chronic rejection?

BACKGROUND

In animal models of acute rejection in lung allografts, bronchus-associated lymphoid tissue (BALT) plays a major role in the induction and persistence of the alloreactive response. We undertook a study of the clinical and histologic associations with BALT identified on transbronchial biopsy in human lung allograft recipients.

METHODS

Transbronchial biopsies of patients receiving single lung, double lung, and combined heart-lung transplantation from 1984 to 1997 at the University of Pittsburgh Medical Center were reviewed. Seventy-seven patients had transbronchial biopsies demonstrating BALT. We examined all pathologic reports and slides, and graded rejection utilizing the Revised Working Formulation for the Classification of Pulmonary Allograft Rejection. Twenty-nine of 77 patients were selected at random to evaluate the distribution of BALT lymphocyte subsets immunohistochemically.

RESULTS

There was no relationship between native disease or the transplant procedure and the identification of BALT. BALT was found from 9 days to 2431 days after transplant (average: 440 days; median: 157 days) in association with clinically insignificant acute cellular rejection (A0, A1) in 75% of cases. Bronchiolitis obliterans developed in 29% of patients with a BALT-positive biopsy, a percentage not different from that of our overall lung transplant population. Immunohistochemical examination of BALT showed helper T cells predominated over cytotoxic T cells in zones surrounding B cell-rich follicular center cells.

CONCLUSIONS

The association of BALT with high-grade acute cellular rejection and with the development of bronchiolitis obliterans could not be confirmed in human lung allografts. BALT most often accompanied A0 or A1 rejection. This raises the possibility that the presence of BALT on transbronchial biopsy may be part of the evolution of immunologic tolerance in human pulmonary allografts.

Erdheim-Chester disease: clinical, radiologic, and histopathologic findings in five patients with interstitial lung disease

Erdheim-Chester disease is a clinicopathologic entity defined by a characteristic pattern of symmetric osteosclerosis caused by an infiltrate of mononuclear cells that include prominent numbers of foamy histiocytes. About half of patients have extraskeletal manifestations, including involvement of the hypothalamus/posterior pituitary, orbit, retroperitoneum, skin, lung, and heart. Pulmonary involvement is an uncommon but important manifestation of Erdheim-Chester disease because it causes significant morbidity and mortality. A review of the Mayo Clinic files produced four patients with confirmed Erdheim-Chester disease in whom lung biopsy had been performed. One additional patient was included from the University of Pittsburgh. Four patients were women. The mean age was 53.6 years (range 25-70 years). All patients had bilateral and symmetric sclerotic bone lesions characteristic of Erdheim-Chester disease, although in three the skeletal abnormalities were discovered only after lung biopsy. Four patients had dyspnea, and one also had a dry cough. One patient died 17 months after diagnosis. Chest radiographs showed diffuse interstitial infiltrates in all patients, with an upper zone predominance in three. Thoracic computed tomography (CT) scans showed thickening of the visceral pleura and interlobular septa with patchy associated fine reticular and centrilobular opacities and ground glass attenuation. Lung biopsy specimens showed an infiltrate of foamy histiocytes, lymphocytes, and scattered Touton giant cells with associated fibrosis in a striking lymphatic distribution. The infiltrate involved visceral pleura, interlobular septa, and bronchovascular bundles. Immunohistochemical stains were positive for CD68 in all cases and S-100 protein in four cases. Stains for CD1a were consistently negative. Ultrastructural studies in one case showed no Birbeck granules. Although in bone the histologic features of Erdheim-Chester disease may overlap with Langerhans' cell histiocytosis, its expression in the lung is distinct. Lung involvement in Erdheim-Chester disease has emerged as a unique radiographic and histologic entity.

Mixed hematopoietic chimerism induces donor-specific tolerance for lung allografts in rodents

Mixed hematopoietic chimerism is a state in which bone marrow hematopoietic stem cells from two genetically different animals coexist. We investigated whether mixed hematopoietic chimerism, resulting from the transplantation of host and donor bone marrow into a lethally irradiated rat, would confer donor-specific tolerance to lung allografts. Recipient rats (Fisher or or Wistar Furth [WF]) were irradiated (1,100 cGy) and reconstituted with a mixture of T-cell-depleted syngeneic plus allogeneic bone marrow. After mixed chimerism was documented by the presence of donor- and host-derived cells in the peripheral blood 4 wk after bone marrow reconstitution, mixed chimeras underwent orthotopic left lung transplantation with donor-specific and third-party lung allografts. No immunosuppressive agents were administered after lung transplantation. All donor-specific lung allografts were accepted by mixed chimeras (n = 40), while all third-party grafts (n = 7) were rejected within 10 d, a time course similar to that for grafts transplanted into naive recipients (n = 14). Radiation control recipients (n = 7) who did not develop mixed chimerism because the donor bone marrow had failed to engraft, also rejected donor-specific grafts within 10 d. We conclude that mixed hematopoietic chimerism induces donor-specific transplantation tolerance to lung allografts.

Detection of micrometastases in histologically negative lymph nodes in esophageal cancer

BACKGROUND

New molecular techniques may identify micrometastases in histologically negative lymph nodes and have an impact on the staging of esophageal cancer. We investigated the role of the reverse transcriptase-polymerase chain reaction (RT-PCR) assay to identify micrometastases in esophageal cancer.

METHODS

The RT-PCR assay to detect carcinoembryonic antigen (CEA) messenger ribonucleic acid (mRNA) was performed on lymph nodes from patients with esophageal cancer and benign esophageal disorders. The presence of CEA mRNA in lymph nodes was considered evidence of metastases.

RESULTS

Histopathologic study revealed metastases in 50 (41%) of 123 lymph nodes from 30 patients with esophageal cancer. All histologically positive lymph nodes contained CEA mRNA by RT-PCR. Of 73 histologically negative lymph nodes, 36 (49%) contained CEA mRNA, a significant increase compared with the histopathologic diagnosis (p < 0.001). Lymph nodes in patients with benign disease contained no CEA mRNA. In 10 patients, histologic stage was NO. Five of them were also negative by RT-PCR, and all are alive with only one recurrence. In the remaining 5 patients, RT-PCR was positive for occult lymph node metastases; 2 have died of disease, and 1 is alive with recurrent disease.

CONCLUSIONS

In patients with esophageal cancer, RT-PCR detects more lymph node metastases than does histopathology. Initial follow-up suggests a positive RT-PCR with negative histologic findings may have poor prognostic implications. Further studies will be needed to confirm any clinical implications.

Bronchioloalveolar adenocarcinoma of lung: monoclonal origin for multifocal disease

In an attempt to understand the histogenesis and molecular pathogenesis of multifocal bronchioloalveolar lung carcinoma (BAC) we studied 28 cases of BAC using a topographic genotyping approach for the presence of K-ras exon 1 mutations and p53 loss of heterozygosity (LOH). This analytical approach demonstrated K-ras exon 1 mutations in 12.5% of solitary BACs, 40% of BACs with microscopic or macroscopic satellite lesions, and 60% of BACs with intrathoracic metastases. In all cases with K-ras mutations, the identical point mutation was present in the primary, satellite, and intrathoracic metastatic lesions. When p53 LOH was demonstrated in the primary lesion, it was also detected in the satellites and intrathoracic metastases. No significant association was noted between the presence of K-ras mutations and p53 LOH. The results strongly support a monoclonal origin of multifocal BACs. Furthermore, the findings support the theories explaining the origin of multifocal BAC by intraalveolar route of spread, intrapulmonary lymphatic spread, or aerosolization leading to implantation at different sites. A trend toward an increased frequency of K-ras mutations and p53 LOH in BACs with satellites or metastases compared to solitary BACs was noted.

Differentiation and programmed cell death-related intermediate biomarkers for the development of non-small cell lung cancer: a pilot study

Fifty samples of lung tissue from patients with non-small cell lung cancer were analyzed for the expression and localization of biomarkers related to squamous differentiation and programmed cell death. These markers include tissue transglutaminase (tTG), keratinocyte transglutaminase (kTG), involucrin, loricrin, and Bcl-2. We found that all of these markers are overexpressed in tumors as compared with histologically normal lung epithelium, where expression is minimal. Expression of the oncoprotein, Bcl-2, increased starting in squamous metaplasia and remained elevated in all lesions, including frank carcinoma. In contrast, expression of the other markers was elevated in the histologically abnormal noninvasive lesions but was decreased somewhat in invasive malignancy. In addition, we found that tTG, kTG, and Bcl-2, when expressed, were detected in mutually exclusive areas. These findings suggest that (1) these markers may prove useful, with more extensive testing and clinical correlation, in predicting risk for the development of lung cancer; and (2) pulmonary carcinogenesis may result from the failure of differentiation and programmed cell death mechanisms in the presence of oncogene overexpression rather than through oncogene/tumor suppressor gene abnormalities alone.

Pulmonary mycotoxicosis: a clinicopathologic study of three cases

Pulmonary mycotoxicosis (PM), also termed organic dust toxic syndrome or silo unloader's syndrome, is an acute illness resulting from massive inhalation of microbial toxins in organic dusts. It has not been well described histologically. Three cases of PM are presented in this report. Open lung biopsies were examined in each case. All of the patients were farmers with no prior lung disease. One had burning in his eyes, throat, and chest after exposure to moldy silage; chills, fever, dry cough, malaise, and weakness developed within 24 hours. Two patients presented with fever, progressive dyspnea, cough, and fatigue within 24 hours of emptying a corncrib, cleaning a chicken coop, and baling hay. Bilateral alveolar and interstitial infiltrates on chest roentgenograms and leukocytosis with neutrophilia were observed in all of the three patients. Two patients became hypoxemic and required mechanical ventilation. Histologic examination showed acute and organizing diffuse alveolar damage in two biopsy specimens and an acute bronchopneumonia in the third. One specimen had 1- to 10-microm ovoid organisms demonstrable with methenamine silver stains; cultures grew Fusarium and Penicillium species. The other two biopsy specimens had negative tissue cultures and special stains for organisms, although Penicillium species were grown from a preoperative bronchoalveolar lavage in one case. The two patients on mechanical ventilation recovered completely with high-dose steroids. The third patient recovered without steroids. No patient had residual functional deficits or chest radiographic abnormalities. PM can be distinguished from allergic and infectious diseases common in individuals exposed to large amounts of organic dust by its clinicopathologic features.