Search

Mediastinal leiomyosarcoma is an aggressive tumor that primarily occurs in the posterior mediastinum. A bronchogenic cyst is a benign lesion that often develops in the mediastinum close to the thoracic trachea and has been reported to be the origin of certain malignancies. The present study reports an extremely rare case of an anterior mediastinal leiomyosarcoma that was considered to have originated from a bronchogenic cyst. An 82‑year‑old woman complained of chest pain, presenting an abnormal 70 mm mass shadow in the anterior mediastinum of a chest CT scan. Mediastinal tumor resection was performed and the tumor was diagnosed as a leiomyosarcoma. As the tumor was located adjacent to a bronchogenic cyst, it was considered to have originated from the remnant tissue of the cyst. Recurrent lesions were noted in the right lower lobe on CT scan 24 months after surgery.

Invasion has a significant role in cancer progression, including expansion to surrounding tissue and metastasis. Previously, we assessed the invasive ability of cancer cells using an easy-to-prepare double-layered collagen gel hemisphere (DL-CGH) method by which cancer cell invasion can be easily visualized. The present study examined multiple lung adenocarcinoma and malignant pleural mesothelioma (MPM) cell lines using the DL-CGH method and identified inherently invasive cell lines. Next, by comparing gene expression between invasive and non-invasive cells by cDNA microarray, the potential candidate gene brain-expressed x-linked protein 1 (Bex1) was identified to be involved in cancer invasion, as it was highly expressed in the invasive cell lines. Downregulation of Bex1 suppressed the invasion and proliferation of the invasive tumor cell lines. The findings of the present study suggested that Bex1 may promote metastasis in vivo and could be a potential oncogene and molecular therapeutic target in lung adenocarcinoma and MPM.

We previously reported that cancer cells may be detected through pleural lavage cytology (PLC). In this study, we sought to re-examine the prognostic significance of the PLC status based on an extended dataset with an additional follow-up period. Pleural lavage following thoracotomy was cytologically examined in 1,317 consecutive patients who were diagnosed with NSCLC between 1987 and 2004 at the Thoracic Surgery Units of Kobe University Graduate School of Medicine and Hyogo Cancer Center. Among the investigated patients, 46 exhibited positive cytological findings. The prognosis of these patients was significantly worse compared to that of patients without positive PLC. Of the 844 pathological stage I patients, 18 had a positive PLC status and their prognosis was significantly worse compared to that of patients with stage I disease without positive PLC. In conclusion, positive PLC findings were associated with a poor prognosis and this finding was significant for patients with stage I disease. These results suggest the need for PLC status evaluation during staging and treatment planning in patients with NSCLC.

Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a rare and aggressive malignant tumor, which was proposed as a novel type of neuroendocrine tumor in 1991. Although it is categorized as a non-small cell lung carcinoma, the precise pathological condition is unknown due to its rare occurrence. The present study outlines the case of a patient presenting with an LCNEC that exhibited pagetoid spread from the region of the primary tumor to the bronchial epithelium (distance, >30 mm). The pagetoid spread was unconfirmed preoperatively, however, was identified by intraoperative rapid diagnosis. This caused us to suffer the perioperative decision of additional resection and resulted in an incomplete resection, as suture of the bronchus was not possible. Pagetoid spread, which is often apparent in the breast, presents as a rare pattern of infiltration of cancer cells when a massive carcinoma is identified beneath the intraepithelial spread. Although preoperative diagnosis of pagetoid spread is difficult due to its rarity and undefined clinical features, it is important for surgeons and pathologists treating lung cancer patients to be aware of potential pagetoid spread in the thoracic region.

E1B55K adenovirus codes the protein that inactivates the p53 protein of host cells and facilitates its own cell proliferation. We prepared E1B55K-deleted adenovirus and investigated its cytopathic effects in primary lung cancer cells to evaluate the possibility of its application in gene therapy. A p53 wild-type small cell lung cancer cell line (SBC3) and three p53 mutant cell lines (SBC5, small cell lung cancer; PC3, adenocarcinoma; and EBC1, squamous cell carcinoma) were infected with AxE1AdB, in which the E1B55K gene was deleted, to assess the cytotoxicity and induction of apoptosis. Moreover, the mRNA expression in virus-infected cells was studied with cDNA array analysis to investigate the response of cancer cells to the virus infection. As a result, AxE1AdB had no detectable cytopathic effect on SBC3 cells, and SBC3 cells continued to replicate. In contrast, AxE1AdB killed SBC5, PC3, and EBC1 cells with great efficiency. In SBC3, apoptosis of the host cells was observed in the early infection stage; in the p53-mutant cell lines, apoptosis of the cells was restricted. An analysis of gene expression in the host cells indicated a significant increase of Bax mRNA in SBC3 and its deficiency in SBC5. Overall, our results suggest that AxE1AdB replicated selectively in the p53-mutant lung cancer cells and showed strong cytotoxicity against them. In the p53-intact cells, p53 induced apoptosis through Bax expression and prevented virus replication and escalation of the infection.

DNA damage sensor proteins are recognized as upstream components of the DNA damage checkpoint signaling pathway and are required for cell cycle control and the induction of apoptosis. hRad9 plays an important role as an upstream regulator of checkpoint signaling. In our previous studies, we confirmed the significant accumulation of hRad9 in the nuclei of tumor cells in surgically-resected non-small cell lung cancer (NSCLC) specimens. We also found that the capacity to produce a functional hRad9 protein was intact in lung cancer cells, a finding which suggests that hRad9 would be a vital component in the pathways that lead to the survival and progression of NSCLC. Small interfering RNA targeting hRad9 was transfected into human lung adenocarcinoma A549 and PC3 cells. After the hRad9 knockdown, the cytotoxicity of the transfected cells was measured by a neutral red uptake test, and the G2-M arrest of irradiated cells was examined by flow cytometry. Significant cytotoxicity was observed in the cancer cells in which hRad9 expression was down-regulated. We also detected the inhibition of Chk1 phosphorylation by Western blot analysis. This suggested that hRad9 silencing leads to the impairment of the DNA damage checkpoint signaling pathway in tumor cells. Flow cytometry indicated a reduced population of cells in the G2-M phase, an observation consistent with the findings of several studies that indicated that hRad9 is necessary for G2-M arrest. In conclusion, the current study demonstrated that RNA interference targeting hRad9 in cancer cells leads to the impairment of the DNA damage checkpoint signaling pathway, which appears to be essential for maintaining tumor cell proliferation, and induces cell death. Therefore, hRad9 may be a novel molecular target for lung cancer treatment.