We encountered two cases of thymoma accompanied by pure red cell aplasia and demonstrating clonal rearrangement of the T-cell receptor beta-chain gene (TCR-beta) in lymphocytes. Patient 1 was a 55-year-old man and Patient 2 was a 43-year-old woman. Both had severe anemia and mediastinal tumors. Bone marrow aspiration was performed and pure red cell aplasia diagnosed. Thymoma was the presumptive diagnosis for the mediastinal tumors, and extended thymectomy was performed. The post-operative diagnosis was invasive thymoma (spindle-cell type) in Patient 1 and non-invasive thymoma (mixed lympho-epithelial type) in Patient 2. The cell compositions (%) obtained with T-cell surface marker analysis were as follows: [table: see text] Southern blot analysis disclosed clonal rearrangement of TCR-beta genes in thymoma thymocytes from both patients.

Biological behavior of lung cancer was evaluated by basic study. Malignancy Associated Change is the concept that the nuclear features of normal cells in the vicinity of cancer show subtle morphological difference from those of healthy individuals. The difference was recognized by high resolution cytometry and the expression of MAC cells was correlated with the degree of abnormality of chest diseases. Comparative genomic hybridization and fluorescence in situ hybridization were performed to investigate genetic abnormality of. Multiple genetic abnormalities and chromosomal instability showed poor prognosis. Two dimensional electrophoresis was employed to detect the expression of the specific protein of lung cancer. TAO2 was proved to be specific to well differentiated adenocarcinoma. Also, metabolic analysis will be employed for cell analysis.

Gene therapy is a promising strategy for cancer treatment. The strategy is categorized to some fields based on the anti-cancer mechanism. p53 gene therapy and antisense therapy exert the cytotoxic effect on cancer cells by apoptosis induction. In suicide gene therapy, expressed suicide gene product kills the cancer cells in combination with prodrug which metabolite is cytotoxic agent. Oncolytic virus replicates in the tumor selectively and destroys the cancer cells. Immunogene therapy potentiates the antigenicity of cancer cells or activate the immune effector cells. In antiangiogenesis gene therapy, neovascularization is inhibited with antiangiogenic molecule gene such as angiostatin. On the other hand, bone marrow stem cells are protected from high dose anti-cancer agents by the transfer of multi-drug resistant gene.

Advances in lung cancer research have come from modern technology, allowing the establishment of lung cancer cell lines and experimental model systems, recombinant DNA technology, robust biological and biochemical functional assays in addition to classical methods such as immunohistochemistry. Such work indicates that the aberrant activation of protooncogenes and inactivation of tumor suppressor genes are fundamental processes for lung carcinogenesis. Further improvements such as DNA array technology will continue to unravel the genetic and epigenetic defects in a far more rapid and comprehensive way that was previously possible. This knowledge will lead to a genetic characterization of lung cancer cells and its specific subtypes, which will hopefully translate to new diagnostic and therapeutic gene based strategies. This review focuses on molecular biological techniques that have been used on lung cancer research and discusses future technological approaches.

Studies on cell cycle regulation and cancer genetics have revealed that multiple cell cycle regulatory proteins play key roles in oncogenesis. These can be categorized in three sets. First; p16INK4-Cyclin D1-RB pathway, which controls G1 to S progression of the cell cycle, second; p53 pathway, which is involved in DNA damage repair, and third; p27KIP1 CDK inhibitor, a negative regulator of cell cycle, and decreased expression of which has been correlated to poor prognosis in cancer patients. Among these, p16INK4, RB and p53 are tumor suppressor genes, and p27 has been pointed out to be haplo-insufficient for tumor suppression. Involvement of these cell cycle regulatory proteins in lung cancer will be discussed.

Growth factors are molecules that participate in the control of cell proliferation. They require specific receptors on the target cell and intracellular signaling pathways to transmit the stimulus to the nucleus. Growth factors can stimulate or inhibit cell division. Most of the factors implicated in lung cancer growth are thought to act through positive feedback loops in which factors secreted by the cancer cells bind to receptors on their own surfaces(autocrine stimulation) or those of neighboring cells (paracrine stimulation). Abnormal expression of growth factors, their receptors, or components of their signaling pathways can result in the unrestrained growth of cancer. In this review, we described outlines of the growth factors, their receptors, signal transduction pathways, as well as their clinical applications.

Lung cancer is a leading cause of malignancy-related death in Japan, and its incidence is still rising steeply. Various factors, including cigarette smoking, asbestos, and diet, have been reported to correlate with the development of lung cancer. Of these factors, cigarette smoking is believed as the major carcinogen for lung cancer. Recent studies indicate that cigarette smoke carcinogens cause genetic damages at both oncogenes(K-ras) and tumor suppressor genes(p53) of lung cancer, and hence initiate and promote the development of lung cancer. This article reviews recent advances in the molecular mechanisms of lung cancer carcinogenesis.

Lung cancer is the largest cancer killer of men and women in the world. In addition to the progress made from antismoking primary prevention measures, new tools to help treat patients with lung cancer are emerging from the rapid advances in knowledge of the molecular pathogenesis of lung cancer. These tools include molecular and cellular biology and are starting to provide an insight into how the tumor cells, by altering oncogenes and tumor suppressor genes, achieves growth advantage, uncontrolled proliferation and metastatic behavior via disruption of key cell-cycle regulators and signal transduction cascades. These tools are being translated into clinical strategies to complement surgery, radiotherapy, and chemotherapy and also to assist in primary and secondary prevention efforts. From the current knowledge of the molecular pathogenesis of lung cancer we know that respiratory epithelial cells require many genetic alterations to become invasive and metastatic cancer.

The failure of chemotherapy to eradicate tumor cells is often due to the development of drug resistance. MDR(multidrug resistance) whose one form of resistance results from a decreased intracellular accumulation of the drugs, most often mediated by the overexpression of P-glycoprotein. MRP also related to pump function of cell membrane in acute leukemia. We have developed the new quantitative assay based on real-time PCR to measure expression of drug-resistance related genes such as MDR-1 and MRP in clinical samples. These results indicates that real-time PCR system is a reliable method to quantitatively determine drug resistant genes expression, it may be to predict responsiveness to chemotherapy by using this technique.

Wilms' tumor gene WT1 mRNA is a new marker of leukemic blast cells for AML, ALL, and CML. Minimal residual disease(MRD) of leukemia can be detected at frequencies as low as 1 in 10(3) to 10(4) normal bone marrow cells and 1 in 10(5) normal peripheral blood mononuclear cells by means of the quantitation of WT1 mRNA(WT1 assay) using reverse transcriptase-polymerase chain reaction. Thus, the WT1 assay makes it possible to rapidly assess the effectiveness of treatment and to evaluate the degree of eradication of leukemic cell in individual leukemia patients. Furthermore, WT1 assay can continuously assess the disease progression of myelodysplastic syndromes(MDS) and predict the evolution of MDS to overt AML within 6 months.

Molecular-based diagnosis of thyroid carcinomas can be more easily established by utilizing specific mRNAs that are restrictedly expressed in cancer tissues. In light of this aspect, we searched for cancer-specific mRNAs using sequence specific-differential display(SS-DD) and serial analysis of gene expression(SAGE). By these techniques, we found several mRNAs that efficiently distinguished benign and malignant tissues. Among these, oncofetal fibronectin(onfFN) mRNA was expressed only in thyroid papillary and anaplastic carcinomas and it was considered the most preferable target for molecular-based diagnosis of these carcinomas. In a previous study, we introduced a new method of preoperative diagnosing thyroid carcinomas. This technique, aspiration biopsy-RT-PCR(ABRP), allows us to simultaneously perform cytological and molecular-based diagnoses by extracting RNA from leftover cells within the needle used for fine needle aspiration biopsies(FNABs). ABRP provides both RNA information and cytological diagnosis without further invasion to the patient. We demonstrated that by ABRP detection of onfFN mRNA in FNABs, papillary and anaplastic carcinomas may be accurately diagnosed preoperatively. Further, by real-time monitoring RT-PCR measurement of onfFN mRNA, a fully automated system was established.

During malignant transformation, cancer cells acquire multiple genetic alterations that override the normal mechanisms controlling cellular proliferation. In brief, cancer is a disease of genetic abnormalities caused by hereditary and/or environmental factors. Genetic diagnosis for cancer can be divided into four categories: 1) pre-symptomatic diagnosis, 2) existence diagnosis, 3) property diagnosis-prognosis diagnosis and 4) genetic test for gene therapy. 1) For hereditary cancer families, pre-symptomatic diagnosis is available. Individuals with multiple cancers can be diagnosed by microsatellite instability(MSI) test using resected cancer tissues and by genotyping of mismatch repair enzymes. If the genotype abnormality is detected, the propositus can obtain early diagnosis and prevention of cancer, and genetic services of their siblings. 2) Using PCR technology, occult tumor cells can be detected from blood and other biological body fluids, as targets of chimeric transcripts and tissue-specific expressions. 3) Molecular properties of cancer cells are investigated for grading malignancy and therapeutic sensitivities. Using the molecular properties, prognosis of the patient can be estimated. 4) Following the genetic test results, the specific and superior gene therapy can be applied individually. Post-therapeutic monitoring is also available only by genetic test. After the genome project, the significance of single nucleotide polymorphisms(SNPs) related with cancer will be established, then tailor-made therapy and/or prevention will be applicable to individuals. The ultimate goal of genetic diagnosis would be the final priority to the phenotypic diagnosis.