Pseudomonas aeruginosa reduces the expression of CFTR via post-translational modification of NHERF1.

Pseudomonas aeruginosa infections of the airway cells decrease apical expression of both wild-type (wt) and F508del CFTR through the inhibition of apical endocytic recycling. CFTR endocytic recycling is known to be regulated by its interaction with PDZ domain containing proteins. Recent work has shown that the PDZ domain scaffolding protein NHERF1 finely regulates both wt and F508delCFTR membrane recycling. Here, we investigated the effect of P. aeruginosa infection on NHERF1 post-translational modifications and how this affects CFTR expression in bronchial epithelial cells and in murine lung. Both in vitro in bronchial cells, and in vivo in mice, infection reduced CFTR expression and increased NHERF1 molecular weight through its hyper-phosphorylation and ubquitination as a consequence of both bacterial pilin- and flagellin-mediated host-cell interaction. The ability of P. aeruginosa to down-regulate mature CFTR expression was reduced both in vivo in NHERF1 knockout mice and in vitro after silencing NHERF1 expression or mutations blocking its phosphorylation at serines 279 and 301. These studies provide the first evidence that NHERF1 phosphorylation may negatively regulate its action and, therefore, the assembly and function of multiprotein NHERF1 complexes in response to infection. The identification of molecular mechanisms responsible for these effects could identify novel targets to block potential P. aeruginosa interference with the efficacy of potentiator and/or corrector compounds.

Subepithelial pelvic hematoma (Antopol--Goldman lesion) simulating renal neoplasm: report of a case and review of the literature.

The Antopol-Goldman lesion is a subepithelial pelvic hematoma simulating a renal neoplasm. We report the clinico-pathological features of a single case and a review of the literature. A 76-year-old man presented with flank pain and hematuria. Computed tomography showed a hypodense lesion of 6 cm at the left kidney with filling defect at pyelogram. The patient underwent nephroureterectomy for suspected neoplasm. Macroscopically, a mass of 6 cm was present impinging on the pelvi-caliceal system. Microscopically, the lesion was composed by hemorragic material with feature of an hematoma. A diffuse eosinophilic amorphous material suspicious for amyloid was observed among intra- and extraparenchymal vessels. The Congo-Red staining verified the presence of amyloid. The diagnosis was subepithelial pelvic hematoma with severe amyloidosis. Antopol-Goldman lesion should be kept in mind as a possible differential diagnosis of upper urinary tract lesion to avoid unnecessary nephrectomies. The anamnestic knowledge of amiloydosis may increase this diagnostic hypothesis.

3q26 Amplification and polysomy of chromosome 3 in squamous cell lesions of the lung: a fluorescence in situ hybridization study.

PURPOSE: An overlapping area of gain at 3q26 has been reported in lung squamous cell carcinoma (SCC), but whether this also occurs in preneoplastic/preinvasive squamous cell proliferations and early-stage invasive carcinomas of the lung is still unknown. EXPERIMENTAL DESIGN: We evaluated the prevalence and the clinicopathologic implications of 3q26 amplification and polysomy of chromosome 3 in 31 preneoplastic/preinvasive squamous cell lesions of the bronchial mucosa and in 139 early-stage invasive pulmonary SCC, both of limited growth within the bronchial wall [early hilar SCC (EHSCC)] and involving the pulmonary parenchyma [parenchyma-infiltrating SCC (PISCC)]. Moreover, mRNA expression of two candidate genes (h-TERC and SKI-like), both mapping to the minimal common amplification region, was also studied by quantitative real-time reverse transcription-PCR. RESULTS: 3q26 amplification and polysomy of chromosome 3 were confined to malignant samples, with 37% of invasive SCC, and 27% of severe dysplasias/in situ carcinomas showing these chromosomal abnormalities. Amplification (with minimal common amplification region at 3q26.2), polysomy 3, concurrent amplification and polysomy 3, or other changes (monosomy) were found in 25 SCC and 1 dysplasia, 24 and 2, 2 and 0, and 1 and 0, respectively. Amplification was significantly associated with EHSCC, polysomy 3 with PISCC. 3q26 amplification correlated with increased tumor diameter and a history of smoking, whereas polysomy 3 correlated with tumor diameter, pT class, and p53, p21, and fascin immunoreactivity. No relationship of either 3q26 gain or polysomy was found with patients' survival. Overexpression of h-TERC or SKI-like mRNA was found in 3q26-amplified or polysomic SCC, with higher levels of h-TERC in the former and of SKI-like in the latter. CONCLUSIONS: 3q26 amplification and chromosome 3 polysomy may be related to the development of invasive SCC, with differential distribution in tumor subsets, despite substantial histologic uniformity. Both h-TERC and SKI-like may be involved in tumor progression.

Pleomorphic carcinomas of the lung show a selective distribution of gene products involved in cell differentiation, cell cycle control, tumor growth, and tumor cell motility: a clinicopathologic and immunohistochemical study of 31 cases.

We investigated 31 cases of pleomorphic carcinomas of the lung, with a double component of neoplastic epithelial cells and of spindle and/or giant cells. To correlate the morphologic diversity of these two cell components with their immunophenotype, we evaluated the expression of several gene products involved in cell differentiation (cytokeratins, epithelial membrane antigen, carcinoembryonic antigen, vimentin, S-100 protein, smooth muscle actin, desmin), cell cycle control and apoptosis (p53, p21Waf1, p27Kip1, FHIT), tumor growth (proliferative fraction, assessed by Ki-67 antigen, and microvascular density, assessed by CD34 immunostaining), and tumor cell motility (fascin). We found the epithelial component to be significantly more immunoreactive for cytokeratins, epithelial membrane antigen, carcinoembryonic antigen, cell cycle inhibitors p21Waf1, p27Kip1 and tumor suppressor gene FHIT, whereas the sarcomatoid component, independent of tumor stage and size, was more immunoreactive for vimentin, fascin, and microvascular density. Accordingly, we suggest a model of tumorigenesis whereby the mesenchymal phenotype of pleomorphic cells is likely induced by the selective activation and segregation of several molecules involved in cell differentiation, cell cycle control, and tumor cell growth and motility. Whether pleomorphic carcinomas of the lung are tumors with a dismal prognosis still remains an unsettled issue. In our series, however, stage I pleomorphic carcinomas have the same clinical behavior as ordinary non-small cell lung cancer, and only a high proliferative index (Ki-67 labeling index >35%) is associated with a worse prognosis in these tumors.

Independent value of fascin immunoreactivity for predicting lymph node metastases in typical and atypical pulmonary carcinoids.

Immunoreactivity for fascin, an actin-bundling protein related to cell motility, has been reported in breast, ovary, pancreas, skin, and non-small cell carcinomas, and associated with more advanced disease stage and poorer prognosis. Data on pulmonary neuroendocrine (NE) tumors, however, are lacking. We evaluated the expression of fascin by immunohistochemistry--using two different monoclonal antibodies--in surgical specimens of pulmonary NE tumors of all the diverse histological types from 128 consecutive patients recruited between 1987 and 2001, and investigated its relationship with the presence of lymph node metastases. Overall, fascin immunoreactivity was detected in 5% of 38 typical carcinoids (TC), 35% of 23 atypical carcinoids (AC), 83% of 40 large-cell neuroendocrine carcinomas (LCNEC), and 100% of 27 small-cell lung carcinomas (SCLC) (P<0.001), Normal NE cells or hyperplastic NE tumorlets were consistently unreactive. No statistically significant differences in fascin immunoreactivity were found between the two antibodies. In TC and AC but not high-grade NE tumors, fascin immunoreactivity closely correlated with the occurrence of lymph node metastases, the pN class and the number of involved lymph nodes (P<0.001). It was also significantly associated with an increased proliferative activity (Ki-67 labeling index >5%) (P=0.020), and with either down-regulation or altered subcellular compartmentalization of E-cadherin (P<0.001) and CD99 (P=0.030), two cell adhesion complexes in pulmonary NE tumors. At multivariate analysis, only fascin emerged as an independent predictor of lymph node metastases in this tumor group (HR 30.28; 95% confidence intervals: 1.59-574.49; P=0.023). This study indicates that fascin immunoreactivity may identify subsets of pulmonary carcinoid patients with different metastatic potential to regional lymph nodes. Targeting the fascin pathway could be a novel therapeutic strategy of pulmonary carcinoids.

CD117 immunoreactivity in high-grade neuroendocrine tumors of the lung: a comparative study of 39 large-cell neuroendocrine carcinomas and 27 surgically resected small-cell carcinomas.

Little is known about CD117 prevalence and clinicopathological implications in pulmonary large-cell neuroendocrine carcinoma. We studied CD117 immunoreactivity in surgical specimens from 39 large-cell neuroendocrine carcinomas of stages I-III and 27 limited-disease small-cell carcinomas, 56 typical and atypical carcinoids of the lung, and 10 neuroendocrine tumorlets, including the membrane and cytoplasmic immunostaining patterns. Membrane CD117 immunoreactivity in 5% or more tumor cells was documented in 30 (77%) large-cell neuroendocrine carcinomas and 18 (67%) small-cell carcinomas and 4 (7%) carcinoids, whereas cytoplasmic labeling was seen in 17 (44%) large-cell neuroendocrine carcinomas, 19 (70%) small-cell carcinomas, and 3 (5%) carcinoids. None of the neuroendocrine cells of the normal bronchial epithelium and of 10 tumorlets showed any CD117 immunoreactivity. Cytoplasmic immunostaining was more prevalent in small-cell carcinomas, whereas membrane labeling did not differ between the two types of high-grade carcinomas. Downregulation of CD117 by neoadjuvant chemotherapy was seen in large-cell neuroendocrine carcinomas but not small-cell carcinomas. Multiple linear regression analysis demonstrated a marginal association between cytoplasmic CD117 immunoreactivity and regional lymph node metastasis in small-cell carcinomas but not large-cell neuroendocrine carcinomas. There was no association between CD117 immunoreactivity and survival in either small-cell carcinoma or large-cell neuroendocrine carcinoma patients.

Primary lymphoepithelioma-like carcinoma of the urinary bladder: report of one case with review and update of the literature after a pooled analysis of 43 patients.

BACKGROUND AND OBJECTIVES: Lymphoepithelioma-like carcinoma (LELC) is an undifferentiated epithelial tumor with a dense inflammatory infiltrate that resembles the lymphoepithelioma of the nasopharinx occurring in other sites. Primary LELC of the bladder (LELCB) was first reported by Zukerberg et al in 1991. The incidence of LELCB is 0.4%-1.3% of all bladder carcinomas. The mean age at diagnosis is 69 years. Of the patient population 69% are men. Herein we report on one more case of primary predominant LELCB and review all the English literature concerning this subject after performing a pooled analysis of the cases recorded in the English literature including the present one. MATERIALS AND METHODS: The reports of 43 patients including the present case of primary LELCB from the English literature were collected from 1991 to 2002. Patients were evaluated for age, sex, primary and adjuvant treatments, clinical staging, follow-up and outcome, and disease related survival. The overall patient population was separated into 3 groups according to the LELCB classification of Amin. RESULTS: The overall patient population included 31 males and 12 females. Average age was 68.4 years (range 52-84). LELCB histological subtypes resulted pure in 17 cases (40%), predominant in 16 (37%) and focal in 10 (23%). Mean follow-up was 37.7 months (range 0-216). Outcome resulted as follows: 26 patients (62%) did not show evidence of diasease, 11 (26%) died of disease, 1 (2%) was alive with metastases, and 4 (10%) died for causes unrelated to the primary disease. Survival rate related to specific disease resulted 71%. Mean follow-up was 48.1 in the first group (pure LELCB), 32 in the second (predominant LELCB), and 30.3 in the third one (focal LELCB). Patients with not evidence of disease were 13 (81%) in group 1, 13 (82%) in group 2, and 0 in group 3. Patients who died of their disease resulted 1 (6%) in the first group, 1 (6%) in the second, and 9 (90%) in the third one. Patients who died for disease not related to the primary tumor were 2 (13%) in the first group, 1 (6%) in the second, and 1 (10%) in the third one. One patient (6%) was alive with metastases in group 2. Survival rate related to specific disease resulted 93% in the first group, 93% in the second one, and 0% in the third one. CONCLUSIONS: To date, there are no clear guide lines for the treatment of LELCB. Treatments performed include both deep transurethral resection of the tumor (TUR-B) as well as partial or radical cystectomy, with or without adjuvant treatments including systemic chemotherapy and radiotherapy. The prognosis is favorable for patients presenting with the pure and predominant forms with a diploid DNA pattern and very poor for patients presenting with focal LELCB. Bladder salvage therapy by performing both TUR-B alone or combined with adjuvant systemic chemotherapy may be a reasonable option for patients with pure or predominant LELCB, while radical surgery with adjuvant systemic therapy may be indicated for focal muscle invasive LELCB.

True 3q chromosomal amplification in squamous cell lung carcinoma by FISH and aCGH molecular analysis: impact on targeted drugs.

Squamous lung carcinoma lacks specific "ad hoc" therapies. Amplification of chromosome 3q is the most common genomic aberration and this region harbours genes having role as novel targets for therapeutics. There is no standard definition on how to score and report 3q amplification. False versus true 3q chromosomal amplification in squamous cell lung carcinoma may have tremendous impact on trials involving drugs which target DNA zones mapping on 3q. Forty squamous lung carcinomas were analyzed by FISH to assess chromosome 3q amplification. aCGH was performed as gold-standard to avoid false positive amplifications. Three clustered patterns of fluorescent signals were observed. Eight cases out of 40 (20%) showed ≥8 3q signals. Twenty out of 40 (50%) showed from 3 to 7 signals. The remaining showed two fluorescent signals (30%). When corrected by whole chromosome 3 signals, only cases with ≥8 signals maintained a LSI 3q/CEP3 ratio >2. Only the cases showing 3q amplification by aCGH (+3q25.3-3q27.3) showed ≥8 fluorescent signals at FISH evidencing a 3q/3 ratio >2. The remaining cases showed flat genomic portrait at aCGH on chromosome 3. We concluded that: 1) absolute copy number of 3q chromosomal region may harbour false positive interpretation of 3q amplification in squamous cell carcinoma; 2) a case results truly "amplified for chromosome 3q" when showing ≥8 fluorescent 3q signals; 3) trials involving drugs targeting loci on chromosome 3q in squamous lung carcinoma therapy have to consider false versus true 3q chromosomal amplification.

Flat epithelial atypia on core needle biopsy: which is the right management?

The clinical significance and management (surgical excision vs. follow-up) of the patients with the diagnosis of flat epithelial atypia (FEA) on core needle biopsy (CNB) are actually under discussion. Using standardized criteria and precise terminology, we analyzed retrospectively our CNB diagnosis of FEA, dividing patients with pure FEA as the most advanced pathologic lesion from patients with FEA associated to atypical ductal hyperplasia (FEA+ADH). Both the categories were correlated with radiologic data and findings on subsequent surgery. We evaluated 875 core needle biopsies (11-gauge stereotactic vacuum-assisted procedure), performed over a 5-year period. A CNB diagnosis of pure FEA was made in 33/875 (3.7%) cases; in other 11 (1.2%) cases we observed the coexistence of FEA and ADH. Subsequent surgical excisions were available in 20/33 pure FEA and in 10/11 FEA+ADH: of the 20 patients with pure FEA on CNB, none had either ductal carcinoma in situ or invasive carcinoma in their excisional biopsy, whereas 3/10 (30%) FEA+ADH on CNB showed, at subsequent surgery, more advanced lesions (2 ductal carcinoma in situ, 1 invasive carcinoma). Our results suggest that patients with an 11-gauge vacuum-assisted CNB diagnosis of pure FEA (especially if related to a small radiologic target, completely or almost completely removed by the needle biopsy procedure) could be spared surgical excision and managed with close radiologic follow-up.

Alteration of the E-cadherin/beta-catenin cell adhesion system is common in pulmonary neuroendocrine tumors and is an independent predictor of lymph node metastasis in atypical carcinoids.

BACKGROUND: To the authors' knowledge, little is known regarding the role of E-cadherin/beta-catenin system dysregulation in pulmonary neuroendocrine tumors. METHODS: E-cadherin and beta-catenin immunoreactivity was evaluated in 10 hyperplastic neuroendocrine tumorlets and 210 neuroendocrine tumors, including 96 typical carcinoids (CTs), 35 atypical carcinoids (ACTs), 49 large cell neuroendocrine carcinomas (LCNECs), and 30 small cell lung carcinomas (SCLCs). RESULTS: Normal and hyperplastic bronchial neuroendocrine cells expressed E-cadherin/beta-catenin with an orderly distribution along the cell membrane. Neuroendocrine tumors retained beta-catenin expression in all tumors and E-cadherin in most tumors, with the exception of 2% of LCNECs, 3% of SCLCs and 9% of ACTs. E-cadherin showed a prevalent membrane-associated, linear immunoreactivity in CTs, whereas membrane-disarrayed and cytoplasmic staining was seen in most ACTs, LCNECs, and SCLCs (P < 0.001). beta-Catenin exhibited similar immunoreactivity patterns according to tumor type and a close association with E-cadherin subcellular distribution (P < 0.001). Nuclear accumulation of beta-catenin was found only in seven LCNECs and in two SCLCs. In ACTs, disarrayed immunoreactivity for E-cadherin and/or beta-catenin was associated with a nontrabecular growth pattern, altered expression of the cell-motility marker fascin, and lymph node metastases. Furthermore, a disarrayed E-cadherin distribution pattern was associated with the pathologic lymph node classification and the number of involved lymph nodes. Multivariate analysis confirmed that a disarrayed E-cadherin or beta-catenin pattern was an independent predictor of lymph node metastases in patients with ACT. CONCLUSIONS: The subcellular compartmentalization of the E-cadherin/beta-catenin complex was altered in pulmonary neuroendocrine tumors. This likely affects the tumor growth pattern and cell motility of ACT and was correlated with the occurrence of lymph node metastases.

Lack of prognostic implications of HER-2/neu abnormalities in 345 stage I non-small cell carcinomas (NSCLC) and 207 stage I-III neuroendocrine tumours (NET) of the lung.

HER-2/neu oncogene activation by either gene amplification and/or protein overexpression has been documented in several human malignancies. Irrespective of protein overexpression, HER-2/neu gene amplification is rare in lung cancer and studies on its prevalence and clinicopathological implications in early stage non-small cell lung cancer (NCSLC) and neuroendocrine tumours (NET) of the lung are lacking. We evaluated HER-2/neu abnormalities in 345 Stage I NSCLC and 207 Stage I-III NET of the lung of all the diverse histological types, by using immunohistochemistry and fluorescent in situ hybridization in selected cases. Overall, HER-2/neu immunoreactivity was detected in 23% of 345 NSCLC and in 7% of 207 NET. Gene amplification was seen in only 7 (7.4%) of the immunoreactive tumours, with high-level amplification (HER-2/neu gene to chromosome 17 ratio > 4.0) in 3 adenocarcinomas, 1 squamous-cell carcinoma and 1 large-cell neuroendocrine carcinoma (LCNEC), and low-level amplification (HER-2/neu gene to chromosome 17 ratio from 2.0 to 4.0) in 1 squamous-cell carcinoma and 1 LCNEC. None of tested carcinoids and SCLC showed gene amplification. All but 1 gene amplified case exhibited 2+ or 3+ membrane labeling. No relationship was found between gene amplification or protein overexpression and patients' survival or other clinicopathological variables. HER-2/neu gene amplification and protein overexpression are not closely correlated in lung carcinomas and do not bear any prognostic implication. Among neuroendocrine tumours, LCNEC show a slightly higher prevalence of either HER-2/neu gene amplification or protein overexpression.

Prognostic implications of neuroendocrine differentiation and hormone production in patients with Stage I nonsmall cell lung carcinoma.

BACKGROUND: Approximately 10-20% of nonsmall cell lung carcinomas (NSCLC) show neuroendocrine (NE) differentiation, as evaluated by panendocrine markers or ultrastructural evidence of dense-core secretory granules. However, little is known regarding the prevalence and clinical implications of NE differentiation in patients with Stage I NSCLC. METHODS: The authors analyzed 220 consecutive patients with Stage I NSCLC (pT1-T2N0M0) among 2100 patients with primary lung carcinoma who underwent surgical treatment between 1987 and 1993. Using light microscopy and immunohistochemical staining for synaptophysin, chromogranin A, and respiratory tract-related hormones, 28 NSCLC specimens with NE differentiation (NSCLC-ND) and 11 large cell neuroendocrine carcinoma (LCNEC) specimens were identified. RESULTS: The 28 NSCLC-ND specimens included 15 adenocarcinomas and 13 squamous cell carcinomas. Neoplastic cells with NE features never exceeded 20% in NSCLC-ND specimens, whereas neoplastic cells amounted to 20-90% in LCNEC specimens. NSCLC-ND specimens with > 5% NE-differentiated tumor cells showed increased Ki-67 labeling index (P = 0.007) and invasive phenotype, as evaluated by fascin immunoreactivity (P = 0.021). Patients with adenocarcinoma, but not with squamous cell carcinoma, who had > 5% NE-differentiated cells had a worse clinical course compared with patients who had ordinary NSCLC, with reduced overall survival (P = 0.017) and disease free survival (P = 0.049). In multivariate analysis, NE differentiation > 5% neoplastic cells in patients with adenocarcinoma independently predicted a poorer prognosis (hazard ratio, 2.61; 95% confidence interval, 0.99-6.85). Hormone production was restricted to chromogranin positive NSCLC-ND but did not affect prognosis. CONCLUSIONS: Stage I adenocarcinomas with >or= 5% NE tumor cells are clinically aggressive tumors, similar to LCNEC. Hormone production identifies a more fully developed neuroendocrine phenotype but is not relevant to prognosis. The identification of NE-differentiated cells in patients with NSCLC may have clinical relevance.

CD117 immunoreactivity in stage I adenocarcinoma and squamous cell carcinoma of the lung: relevance to prognosis in a subset of adenocarcinoma patients.

CD117, a trans-membrane tyrosine kinase receptor, has been immunolocalized in a large variety of human neoplasms. Little, however, is known about the prevalence and clinical implications of CD117 in stage I adenocarcinoma and squamous cell carcinoma of the lung. We evaluated 201 consecutive stage I adenocarcinoma and squamous cell carcinoma of the lung for CD117 immunoreactivity (dichotomized as negative or positive if containing less than 5% or >/=5% immunoreactive neoplastic cells, respectively), also taking into account the pattern (either membranous or cytoplasmic), and the intensity of immunostaining in comparison with intratumoral mast cells. The immunostaining results were then correlated with tumor biopathological characteristics and patients' survival. Membranous CD117 immunoreactivity was documented in 19 (22%) of 88 adenocarcinomas and 15 (13%) of 113 squamous cell carcinomas, whereas cytoplasmic labelling was seen in 28 (32%) adenocarcinomas and eight (7%) squamous cell carcinomas. In both tumor types, membranous or cytoplasmic CD117 immunoreactivity was associated with higher proliferative fraction and with features of more aggressive tumor behavior, including higher stage, size and grade, occurrence of clinical symptoms, high microvessel density and neuroendocrine differentiation. Furthermore, immunoreactive tumors exhibited increased levels of bcl-2, cyclin-E, Her-2, p27(Kip1) and fascin, the latter being a marker of tumor cell metastatization in lung cancer. Membranous but not cytoplasmic labelling emerged as an independent risk factor for death and reduced time to progression in adenocarcinoma but not in squamous cell carcinoma patients, when singly adjusted for confounding factors. CD117 immunoreactivity identifies a peculiar subset of stage I adenocarcinoma and squamous cell carcinoma of the lung with highly proliferative tumors and may have prognostic relevance in adenocarcinoma patients. Targeting the CD117 pathway could be a novel therapeutic strategy in a subset of pulmonary carcinomas.

K-ras gene mutational analysis supports a monoclonal origin of biphasic pleomorphic carcinoma of the lung.

We investigated 27 pleomorphic carcinomas of the lung for exon 1 K-ras gene mutations using polymerase chain reaction-single-strand conformation polymophism analysis and direct sequencing. All pleomorphic carcinomas were biphasic, that is, composed of an adeno-, squamous- or large-cell-carcinomatous component associated with a spindle- and/or giant-cell component. Of 27 cases, six (22%) showed K-ras codon 12 mutations, which is a figure higher than that previously reported on in pure sarcoma-like pleomorphic carcinomas. Five tumors displayed the same mutation in both the epithelial and the sarcomatoid components, whereas in one tumor the mutation was restricted to the epithelial component. All mutations occurred in smokers, and were transversions, including GGT (glycine) to TGT (cysteine) change in two cases, to GCT (alanine) in two and to GTT (valine) in two. No significant relationships were found between the occurrence and type of mutations and patients' survival or any other clinicopathological variable, suggesting that K-ras mutations are early events in the development of these tumors. Our results indicate that most, though not all, biphasic pleomorphic carcinomas of the lung are monoclonal in origin, and that cigarette smoking may have a causative role in the development of K-ras alterations in these tumors, as all mutations are transversions.

p63 immunoreactivity in lung cancer: yet another player in the development of squamous cell carcinomas?

The p63 protein, a member of the p53 family of nuclear transcription factors, is characterized by different capabilities of transactivating reporter genes, inducing apoptosis, and functioning as dominant-negative agent. This study evaluated the prevalence and prognostic implications of p63 immunoreactivity in 221 patients with stage I non-small cell lung carcinoma (NSCLC) and in 57 patients with stage I-IV neuroendocrine tumours (NET). The results were correlated with the tumour proliferative fraction, the accumulation of p53 protein, and with patient survival. p63 immunoreactivity was seen in 109/118 squamous cell carcinomas, 15/95 adenocarcinomas, 2/2 adenosquamous carcinomas, 4/6 large cell carcinomas, 9/20 poorly differentiated NET, and 1/37 typical and atypical carcinoids (p < 0.001). Furthermore, the prevalence of p63-immunoreactive cells increased progressively from pre-neoplastic and pre-invasive lesions to invasive squamous cell carcinomas. In these latter tumours, but not in adenocarcinomas, p63 immunoreactivity correlated directly with the tumour proliferative fraction (p = 0.028), and inversely with the tumour grade (p = 0.004). No relationship was found with p53 protein immunoreactivity or the other clinico-pathological variables examined. Although p63 is likely to be involved in the development of pulmonary squamous cell carcinoma, it does not carry any prognostic implication for NSCLC patients.