Alterations of p14ARF, p53, and p73 genes involved in the E2F-1-mediated apoptotic pathways in non-small cell lung carcinoma.

Overexpression of E2F-1 induces apoptosis by both a p14ARF-p53- and a p73-mediated pathway. p14ARF is the alternate tumor suppressor product of the INK4a/ARF locus that is inactivated frequently in lung carcinogenesis. Because p14ARF stabilizes p53, it has been proposed that the loss of p14ARF is functionally equivalent to a p53 mutation. We have tested this hypothesis by examining the genomic status of the unique exon 1beta of p14ARF in 53 human cell lines and 86 primary non-small cell lung carcinomas and correlated this with previously characterized alterations of p53. Homozygous deletions of p14ARF were detected in 12 of 53 (23%) cell lines and 16 of 86 (19%) primary tumors. A single cell line, but no primary tumors, harbored an intragenic mutation. The deletion of p14ARF was inversely correlated with the loss of p53 in the majority of cell lines (P = 0.02), but this relationship was not maintained among primary tumors (P = 0.5). E2F-1 can also induce p73 via a p53-independent apoptotic pathway. Although we did not observe inactivation of p73 by either mutation or DNA methylation, haploinsufficiency of p73 correlated positively with either p14ARF or p53 mutation or both (P = 0.01) in primary non-small cell lung carcinomas. These data are consistent with the current model of p14ARF and p53 interaction as a complex network rather than a simple linear pathway and indicate a possible role for an E2F-1-mediated failsafe, p53-independent, apoptotic pathway involving p73 in human lung carcinogenesis.

Liposarcoma of the pleural cavity: clinical and pathologic features of 4 cases with a review of the literature.

BACKGROUND: Primary liposarcomas of the pleura are extremely rare malignancies, and relatively few reports appear in the world literature. DESIGN: We compiled a small series of 4 cases of primary pleural liposarcoma from the files of the Armed Forces Institute of Pathology (Washington, DC) and compared the histopathologic and clinical features of these 4 cases with those of 9 previously published cases. RESULTS: Our investigation included the case studies of 9 men and 4 women, aged 19 to 80 years (average, 49 years). Histologic subtypes in the 9 cases with available information included 5 myxoid liposarcomas, 1 well-differentiated liposarcoma, and 3 liposarcomas with mixtures of histologic types. Surgical resection with or without chemotherapy appeared to be the most common form of treatment, although radiation therapy was used in some cases and seemed beneficial. Survival information was available for 11 cases; 4 patients died of disease at 7, 9, 12, and 19 months; 1 died of heart failure 2 days after presentation; 1 died of unknown causes 16 months after presentation; and 3 patients were alive without tumor at 5, 16, and 66 months after diagnosis. One patient had local recurrence at 2 years. A second surgical resection in this patient failed, and he died of disease 9 years after initial presentation. A second patient experienced recurrence at 4 years and was free of disease 4 years after the second surgical resection. CONCLUSIONS: Primary pleural liposarcomas occur predominantly in older men, and the myxoid histologic subtype is the most common. Radiographic or surgical evaluation is important to distinguish primary pleural liposarcoma from chest wall or mediastinal sarcomas, as well as metastases from other sites. Although further investigation is needed, evidence from the cases reviewed here indicates that surgical resection with adjuvant radiation therapy may benefit patients with primary pleural liposarcoma.

Expression of the CD44 cell adhesion molecule in urinary bladder transitional cell carcinoma.

CD44 cell adhesion molecule (PgP-1, ECM III, Hermes antigen) is a polymorphic integral membrane glycoprotein associated with cell matrix adhesion, lymphocyte activation, recirculation, and homing. CD44 expression has been reported in in malignant lymphoma and in a variety of epithelial human cancers but has not been studied as a prognostic marker in urinary bladder transitional cell carcinoma. CD44s (standard 85- to 95-kDa macromolecule) expression was measured by qualitative and image analysis-quantitated immunohistochemical techniques using the A3D8 monoclonal antibody. CD44v6 (a splice variant exon of CD44s) expression was measured by qualitative immunohistochemical techniques using the 2F10 monoclonal antibody. The results of CD44s and CD44v6 expression were compared with tumor grade, pathologic stage, and DNA content analysis on Feulgen-stained tissue sections in 44 cases of urinary bladder transitional cell carcinoma. The mean percentage-positive area of staining intensity for CD44s expression in Grade 1 tumors was 61%, compared with 30% for the Grade 3 tumors (P < 0.001). Non-invasive tumors featured a 59%-positive area of staining intensity, compared with the 30% staining percentage for the deeply invasive tumors (P < 0.001). There was significant correlation of aneuploid DNA content with loss of CD44s staining (P < 0.05). The staining results for CD44v6 paralleled those for the CD44s, with a significant loss of staining in high-grade and high-stage aggressive tumors in comparison with the low-grade nonaggressive tumors (P < 0.01). In urinary bladder transitional cell carcinoma, CD44s and CD44v6 expression parallels that for other cell adhesion molecules, such as E-cadherin, that feature a significant progressive loss of immunoreactivity in association with tumor dedifferentiation, advancing pathologic stage, and abnormal DNA content.

Parotid involvement by desmoplastic melanoma.

Desmoplastic malignant melanoma often arises in sun damaged skin of the head and neck and shows frequent neurotropism. Although metastatic melanoma frequently involve the parotid, direct spread to the parotid has been rarely reported. We evaluated five cases of desmoplastic malignant melanoma involving the parotid gland with clinical and pathological evidence of precursor cutaneous lesions in four of the five cases. The parotid involvement in four cases was tumoural, and three of these were not clinically suspected to be melanoma. The histological appearance in all five cases was that of a sarcomatoid tumour. Immunohistochemistry and electronmicroscopy performed on three of the cases showed only evidence of schwannian differentiation: the tumour cells were positive for S-100 protein and vimentin, and negative for cytokeratin and HMB-45. Electronmicroscopy showed no evidence of melanogenesis. All five tumours showed histological evidence of prominent neurotropism with one case demonstrating extension from overlying skin along cutaneous nerves to the superficial parotid. Thus, desmoplastic malignant melanoma may involve the parotid by neurotropic spread and can be pathologically indistinguishable from malignant schwannoma, a diagnosis which may be made erroneously in the absence of clinical information.