AXIN1 mutations but not deletions in cerebellar medulloblastomas

Medulloblastoma is a malignant, invasive embryonal tumour of the cerebellum which manifests preferentially in children. A subset of cases is associated with colon cancer and APC germline mutations (Turcot syndrome), and APC and beta-catenin point mutations occur in up to 10% of sporadic cases, indicating the involvement of the Wnt pathway in the development of medulloblastoma. In 39 sporadic cerebellar medulloblastomas screeened for alterations in the AXIN1 gene, another component of the Wnt pathway, we found missense AXIN1 mutations in two tumours, CCC-->TCC at codon 255 (exon 1, Pro-->Ser) and TCT-->TGT at codon 263 (exon 1, Ser-->Cys). Furthermore, the A allele at the G/A polymorphism at nucleotide 16 in intron 4 was significantly over-represented in medulloblastomas (39 cases; G 0.76 vs-A 0.24) compared to healthy individuals (86 cases; G 0.91 vs A 0.09; P=0.0027). RT-PCR revealed large deletions in the AXIN1 gene in 5/12 (42%) medulloblastomas, consistent with a previous report. However, we observed such deletions at a similar frequency also in normal brain tissue (6/12, 50%). Since there are multiple complementary, inverted sequences present in the AXIN1 gene, these large deletions may represent RT-PCR errors due to stem-loop secondary structures.     

Immunocytochemical markers in acute leukaemias diagnosis

The study included 1742 patients with acute myeloblastic leukaemias (AML) and acute lymphoblastic leukaemias (ALL), Kyiv city residents and patients from 20 regions of Ukraine. Bone marrow and blood smears were sent at diagnosis to Reference Center. The analysis was based on May-Grünvald-Giemza (MGG) stain and cytochemical reactions (MPO, acNSE, CAE, AP, PAS). Immunocytochemical techniques (APAAP, LSAB) and broad panel of monoclonal antibodies (MoAbs) against lineage specific and differentiation antigens of leukocytes were employed for immunophenotyping of leukemic blast cells directly in blood and bone marrow smears. Different types of AML were defined by the expression of the cell surface and cytoplasmic antigens. Immunocytochemical study was required especially in diagnosing of AML with minimal differentiation, acute megakaryoblastic leukaemia, acute erythroid leukaemia and acute leukaemias of ambiguous lineage. Acute lymphoblastic leukaemias was broadly classified into B-lineage and T-lineage ALL. According to the degree of B-lymphoid differentiation of the blast cells four subtypes of B-lineage ALL were established. T-lineage ALL observed in patients were also divided into four subtypes. Immunocytochemical examination was required to diagnose AL of ambiguous lineage with no clear evidence of lineage differentiation (acute undifferentiated leukaemia) or those with blasts that express markers of more than one lineage (mixed phenotype acute leukaemias).     

Genetic alterations in mouse medulloblastomas and generation of tumors de novo from primary cerebellar granule neuron precursors

Mice lacking p53 and one or two alleles of the cyclin D-dependent kinase inhibitor p18(Ink4c) are prone to medulloblastoma development. The tumor frequency is increased by exposing postnatal animals to ionizing radiation at a time when their cerebella are developing. In irradiated mice engineered to express a floxed p53 allele and a Nestin-Cre transgene, tumor development can be restricted to the brain. Analysis of these animals indicated that inactivation of one or both Ink4c alleles did not affect the time of medulloblastoma onset but increased tumor invasiveness. All such tumors exhibited complete loss of function of the Patched 1 (Ptc1) gene encoding the receptor for sonic hedgehog, and many exhibited other recurrent genetic alterations, including trisomy of chromosome 6, amplification of N-Myc, modest increases in copy number of the Ccnd1 gene encoding cyclin D1, and other complex chromosomal rearrangements. In contrast, medulloblastomas arising in Ptc1(+/-) mice lacking one or both Ink4c alleles retained p53 function and exhibited only limited genomic instability. Nonetheless, complete inactivation of the wild-type Ptc1 allele was a universal event, and trisomy of chromosome 6 was again frequent. The enforced expression of N-Myc or cyclin D1 in primary cerebellar granule neuron precursors isolated from Ink4c(-/-), p53(-/-) mice enabled the cells to initiate medulloblastomas when injected back into the brains of immunocompromised recipient animals. These "engineered" tumors exhibited gene expression profiles indistinguishable from those of medulloblastomas that arose spontaneously. These results underscore the functional interplay between a network of specific genes that recurrently contribute to medulloblastoma formation.     

Evidence in medulloblastomas

Medulloblastoma is the most common infratentorial malignant tumour under 15 years of age. In recent protocols, the patients are stratified for treatment in standard risk or high risk, according to the clinical variables as age, localized or disseminated disease, degree of surgical resection and more recently expected biological behaviour based on retrospective and prospective studies of former samples analyzed. The objectives for future treatments are reduce morbidity without jeopardizing survival.     

Immunocytochemical evidence for gastric proteases in adenocarcinoma of the stomach

When anti-sera to bovine pepsinogen and chymosin (rennin) was used, immunoreactive tumor cells were found in 12 of 23 gastric adenocarcinomas irrespective of the tumor subtype, degree of differentiation, or the presence or absence of intestinal metaplasia in the adjacent gastric mucosa. Nine of ten lymph node metastases contained immunoreactive tumor cells. Except for focal positively staining acini in Brunner's glands the antibodies did not stain normal small intestine or areas of intestinal metaplasia. Although intestinal metaplasia is a predisposing factor in gastric carcinoma it may be irrelevant to its histogenesis and differentiation. Instead, the mucus neck cells, being the stem cells of the normal gastric mucosa, may be the target of malignant transformation in gastric carcinoma.     

New molecular markers in resistant B-CLL

B-chronic lymphocytic leukemia (B-CLL) is characterized by a highly variable clinical course which has long remained a stumbling block for clinicians. This variability appears to arise from complex molecular alterations identified in malignant cells from patient subsets. Recent studies have focused in particular on identifying new molecular markers to help predict the most effective and adapted treatments. In addition to the mutation status of immunoglobulin variable heavy-chain region (IgV_H) genes, which is a well-established predictive factor in B-CLL, these new markers include defects of cell factors involved in the maintenance of genome stability, such as telomere function, DNA repair, ATM and p53. Other predictive factors, such as tyrosine kinase Zap-70 and soluble factors found in patient sera, may be associated with B-cell receptor signal transduction. Interestingly, an alteration of these factors fits closely, though not strikingly, with the absence of somatic mutations in IgV_H genes, suggesting that the latter may be due either to epigenetic events leading to an unstable genome or to an inherited defect in the immune response of malignant B-cells. Recent lessons from Zap-70 expression/phosphorylation suggest that some of these markers may reflect the defective pathways in B-CLL cells rather than being markers of cell malignancy per se. Furthermore, specific subsets of markers are found in patient cells resistant to treatment. Current studies on gene expression profiling and proteomic analyses should soon lead to a better understanding of how these pathways are affected, especially in multi-drug resistant B-CLL.     

Emerging molecular markers of cancer

Alterations in gene sequences, expression levels and protein structure or function have been associated with every type of cancer. These 'molecular markers' can be useful in detecting cancer, determining prognosis and monitoring disease progression or therapeutic response. But what is the best way to identify molecular markers and can they be easily incorporated into the clinical setting?     

Molecular studies in pediatric medulloblastomas

Ten pediatric medulloblastoma patients were analyzed for DNA content, cell cycle, expression of drug resistance, apoptosis, cell proliferation, andN-myc genes to determine their prognostic significance. Medulloblastoma patients with progressive disease had fourth ventricle foraminal extension and larger tumors in the imaging studies. Patients with aneuploid tumors responded well to treatment regimens as compared with those with diploid tumors. Cell cycle analysis showed that the patients with progressive disease had a high S-phase fraction in the tumor cell population as compared with patients with favorable response to treatment. The correlation coefficients betweenBcl-2 andMRP, Bcl-2 andBax, p53 andp21, as well asKi67 andPCNA were positive and significant, indicating their possible coregulated expression. The relationship between these markers indicates their relative and cumulative effect on cellular drug resistance, apoptosis, and/or cell proliferation in pediatric medulloblastomas.     

Breast cancer and molecular markers

Molecular markers have long been studied and used in part as a marker for prediction of prognosis and deciding the treatment for patients with breast cancer. Now development of novel decision-making biomarkers for adjuvant chemotherapy is desired for many patients with hormone receptor-positive early breast cancer. Thanks to recent advances in molecular marker studies on breast cancer, the update committee has systematically reviewed the literature and updated recommendations for the use of tumor markers in breast cancer, one of the ASCO clinical practice guidelines, in 2007. In the revised guideline, gene expression profiling assays are topics in six newly added categories. In this review, the key guideline recommendations and two innovative gene expression profiling assays have been summarized.     

Prognostic molecular markers in early breast cancer

A multitude of molecules involved in breast cancer biology have been studied as potential prognostic markers. In the present review we discuss the role of established molecular markers, as well as potential applications of emerging new technologies. Those molecules used routinely to make treatment decisions in patients with early-stage breast cancer include markers of proliferation (e.g. Ki-67), hormone receptors, and the human epidermal growth factor receptor 2. Tumor markers shown to have prognostic value but not used routinely include cyclin D₁ and cyclin E, urokinase-like plasminogen activator/plasminogen activator inhibitor, and cathepsin D. The level of evidence for other molecular markers is lower, in part because most studies were retrospective and not adequately powered, making their findings unsuitable for choosing treatments for individual patients. Gene microarrays have been successfuly used to classify breast cancers into subtypes with specific gene expression profiles and to evaluate prognosis. RT-PCR has also been used to evaluate expression of multiple genes in archival tissue. Proteomics technologies are in development.     

鼻咽癌转移相关的分子指标研究进展

转移是鼻咽癌治疗失败的主要原因.预测鼻咽癌患者远处转移的风险对于判断预后及指导综合治疗的实施具有重要意义.现概述近年来在分子水平与鼻咽癌转移相关的多种指标的研究进展.     

肺癌转移相关分子标记物研究进展

转移是导致肺癌死亡率居高不下的主要原因.肺癌转移的研究已经深入到分子水平,许多分子标记物被证实参与转移过程,包括胸苷酸合成酶、肿瘤脉管生成相关因子、细胞黏附分子、细胞外基质降解相关金属蛋白酶、细胞因子及转移相关基因等.明确肺癌转移的分子机制将有助于肺癌转移的早期诊治.     

Role of molecular markers in breast cancer therapy

<正>Translational research,in general,means to take knowledge from one area into a second.Traditional thought to represent transfer of knowledge from basic research into the clinic,translational research today covers a much broader term.Thus,most investigators will agree translational research covers a two-way process that also includes taking lessons from the clinic back to the laboratory,by which biological observations in vivo would create novel hypotheses to be further explored in laboratory experiments.     

Histopathologic grading of adult medulloblastomas

BACKGROUND: Histopathologic evaluation of the degree and extent of anaplasia is a useful prognostic parameter in pediatric medulloblastomas. Whether the same applies to adult medulloblastomas is not known. METHODS: The study included 74 adult patients with histologically confirmed medulloblastomas and retrospectively reassessed 67 cases with available slides for the presence of nodularity, collagen deposition (desmoplasia without nodules), and degree and extent of anaplasia. RESULTS: Patients included 43 men and 31 women with the following age distribution: 18-40 years (84%); 41-50 years (9%); and 51-70 years (7%). At last follow-up, 56 patients were alive with a mean follow-up of 6.3 years (range, 0.1-20.8 years). A variety of treatments were employed during the study period, including postoperative radiation (85%) and chemotherapy (27%). Precise treatment modalities were unknown in 12% of patients. Anaplasia was absent (34%), mild (34%), moderate (27%), or severe (5%). Severe anaplasia was diffuse in 2 cases and focal in 1, although in the latter cases severe anaplasia was diffusely present at the time of disease recurrence. Male sex was associated with decreased 10-year recurrence-free survival (40% vs 66%; P = .021) and overall survival (38% vs 68%; P = .005). Severe anaplasia at first resection was found to be an independent predictor of decreased recurrence-free survival (P = .005) and overall survival (P = .015). CONCLUSIONS: The incidence of severe anaplasia in adult medulloblastomas is lower than in the pediatric population. Male sex and the presence of severe anaplasia at the time of first resection are predictors of decreased recurrence-free and overall survival. However, the significance of severe anaplasia should be regarded with caution based on the small number of tumors with this feature in the current study.     

Cell kinetics of medulloblastomas.

BACKGROUND. Cell kinetics and clinical behavior were correlated for 22 primary and 10 recurrent or metastatic medulloblastomas from 30 patients. METHODS. Twenty-six patients received bromodeoxyuridine (BUdR) intravenously during craniotomy; excised specimens were stained by the immunoperoxidase method. The BUdR labeling index (LI) was calculated. Four patients received a pulse of tritiated thymidine; LI was calculated autoradiographically. RESULTS. The mean LI for 32 tumors (11.7 +/- 1.3% standard error) indicated high proliferative potential. LI appeared higher in tumors from younger patients and those in the cerebellar hemisphere as compared with those in the cerebellar vermis. LI did not correlate with survival time. In six BUdR-labeled tumors labeled with iododeoxyuridine, the S-phase duration was 6.1-11.3 hours (mean, 8.0 +/- 0.8 hours); the potential doubling time was 25-82 hours. The actual doubling time, estimated in three cases from serial imaging, was 20-24 days. A cell loss factor of approximately 0.90 was assumed. CONCLUSION. A high LI may reflect rapid medulloblastoma growth, but survival seemed more dependent on sensitivity to radiation therapy.     

Epidemiological study using molecular biologic markers

It seems to be important for the epidemiological study on cancer etiology to conduct molecular biological approach. IARC/WHO held "International Course on Molecular Biology for Epidemiologist" in order to promote the molecular epidemiology. I described here the content of the course and our study on lung cancer etiology using c-Ha-ras VTR marker of leukocyte DNA in peripheral blood, and discussed the possibility of molecular epidemiology.