Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Tissue microdissection”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,261 records · Page 70Linked to original sources
PubMed2000

X-chromosome inactivation in the human trophoblast of early pregnancy.

To investigate X-chromosome inactivation (XCI) in human trophoblasts during early pregnancy, trophoblast genomic DNA was extracted and analyzed for a Bst XI restriction endonuclease site polymorphism in the X-linked phosphoglycerate kinase gene, after digestion with methylation-sensitive Hpa II (control samples were digested instead with Afa I). Six villous trophoblast DNA samples were informative for the polymorphism (ie, heterozygous) and were derived from women homozygous for the polymorphism. These samples were then evaluated for XCI. In five of the six samples with Hpa II predigestion, the sizes of the two heterozygous band peaks differed; maternal X-chromosome (X(M))-derived alleles showed smaller peak sizes than paternal X-chromosome (X(P))-derived alleles, but the differences varied in degree. In samples obtained by microdissection from formalin-fixed, paraffin-embedded tissues (30 samples from different anchoring villi, and 38 samples from different branch villi), monoclonal band patterns of X(P)-derived alleles were observed more frequently than those of X(M)-derived alleles, but almost half of the samples showed polyclonal patterns. Our results suggest that a skewing of XCI exists in the human trophoblast; however, the degree of nonrandomness due to predominant X(P) inactivation appears to be restricted. It is probable that transcription of the X inactivation center (XIC) begins earlier in mice than in humans.

Clone Cells↗
PubMed2005

Multi-transcriptional profiling of melanin-concentrating hormone and orexin-containing neurons.

1.Melanin-concentrating hormone (MCH) and orexin-containing neurons participate in hypothalamic circuits that control energy homeostasis. While these two systems have projections to widespread target areas within the central nervous system, little is known about intrinsic characteristics and the molecular composition of both the MCH and orexin neurons themselves. 2. By a combinatory approach of quantitative immunocytochemical identification and analysis with laser microdissection and semi-quantitative Real-time RT-PCR, here we present multi-transcriptional profiling of MCH and orexin neurons in the rat lateral hypothalamus. 3. Immunocytochemical analysis showed that orexin peptide expression was increased after fasting both during the activity and resting period of rats, whereas MCH peptide content was only clearly upregulated at resting phase. Subsequent transcriptional profiling showed distinct expression patterns of MCH, orexin and cocaine-amphetamine regulated transcript (CART) between MCH and orexin neurons. A low expression level of dynorphin was found both in MCH and orexin neurons. Receptor expression profiles, reflecting interaction with neuropeptide Y, melanocortins, leptin, glucocorticoids and GABA, showed approximately similar expression patterns among the MCH and orexin neuronal systems. Expression of glutamate- and GABA-markers revealed a possible contributory role of both glutamate and GABA in functional output of MCH and orexin neurons. 4. This method allowed differential screening at mRNA level after immunocytochemical neuron identification and analysis in heterogeneous brain regions, which can further specify functioning of the individual neurons. With respect to MCH and orexin neurons, this study emphasizes that these neurons are targets for stimulatory and inhibitory signals from other brain regions including the arcuate nucleus and the general circulation. Additionally, both glutamate and GABA appear to be involved in MCH and orexin neuronal functioning related to feeding and regulation of the energy balance.

Animals↗
PubMed2006

From punch to profile.

In this essay an aspect of my research is highlighted that has its roots in the mid seventies with the implementation of the 'Palkovits punch' procedure. This methodology was introduced when radiochemical and radio-immunoassay methods became sufficiently sensitive to measure key molecules for chemical neurotransmission and metabolism in minute amounts of brain tissue. For application of today's laser guided microdissection this knowledge of functional neuro-anatomy is indispensable.

Brain↗
PubMed2004

Large-scale mitochondrial DNA deletion mutations and nuclear genome instability in human breast cancer.

Deletion mutations in mitochondrial (mt) DNA (mtDNA) as well as microsatellite instability (MSI) and loss of heterozygosity (LOH) in nuclear DNA (nDNA) exist in human cancer. We determined if: (1) large-scale mtDNA deletion mutations were present in cancerous and not in normal breast tissue, and (2) combining mt- and nDNA findings would provide complementary information to identify breast cancer. Thirty-nine matched breast cancer/histologically normal and 23 "true" normal tissue samples from women without breast cancer were microdissected and DNA extracted. 4977, approximately 3938, approximately 4388 and approximately 4576bp deletions were observed, with the 4576bp deletion being present in 0% of true normal, 13% of histologically normal specimens from a cancerous breast and 77% of breast cancers. The other three deletions were not specific to a breast containing cancer. LOH was found in 66.7% and MSI in 38.5% of samples. 38/39 (97.4%) tumors had at least one nDNA or 4576bp mtDNA alteration, suggesting that mt- and nDNA analysis provides complementary information in breast cancer detection. The 4576bp deletion appears to indicate cancer in the breast. The higher mtDNA copy number in cancer coupled with a mtDNA deletion mutation which appears specific for breasts which contain cancer may prove to be a good target to screen for cancer in the breast, including specimens of low and/or mixed cellularity.

Alleles↗
PubMed2026

Molecular subgroups of human malignant peripheral nerve sheath tumors are conserved in canines.

Malignant peripheral nerve sheath tumors (MPNST) are aggressive sarcomas of Schwann cell lineage with poor prognosis in both humans and dogs. While rare in humans, MPNSTs occur more frequently in dogs and share histomorphological and clinical features. Recent methylome and transcriptome analyses have identified two molecular subgroups of human MPNST with distinct oncogenic signaling pathways and prognostic implications; however, it remains unclear if these subgroups also exist in canines. Given their higher incidence and biological similarities to human disease, canine MPNSTs represent a promising comparative model to investigate molecular subtypes and evaluate novel therapeutic strategies. To characterize canine MPNST and assess molecular parallels with the human subgroups, we applied laser-capture microdissection (LCM) followed by RNAsequencing to analyze tumor tissue from 20 canine MPNST. Principle component and differential gene expression analyses identified two clearly distinct transcriptional clusters corresponding to spindle cell and epithelioid MPNST variants, respectively. Unsupervised cross-species comparison aligned the two canine clusters with the human G1 and G2 subgroups. Accordingly, one cluster was characterized by SHH pathway activation and increased cell cycle activity, while the other showed non-canonical WNT pathway, Schwann cell-like features and marked macrophage infiltration. Immunohistochemistry further demonstrated loss of H3K27me3, p-ERK activation and β-catenin signaling by IHC in a subset of tumors. These findings support the value of canine MPNST as clinically amenable model for structured assessment of novel therapeutic approaches to benefit patients of both species.

Canine cancer model↗
PubMed2002

Quantitative assessment of promoter hypermethylation during breast cancer development.

The aberrant methylation of cytosine residues in the promoter region of growth regulatory genes is now widely recognized as an additional mechanism for gene inactivation in cancer cells. In this study we analyzed the methylation status of four growth regulatory genes (p16, RASSF1A, cyclinD2, 14-3-3zeta) during breast cancer progression. For this purpose invasive and noninvasive tumor cell populations as well as hyperplastic cell proliferations were isolated from a series of archival breast tissue specimens (n = 57) using laser-assisted microdissection. A new real-time polymerase chain reaction-based assay was used for the sensitive and quantitative determination of the cell-specific methylation status. We found that aberrant promoter methylation was already prevalent in pure intraductal carcinoma with different frequencies and different methylation levels for the four genes analyzed. For RASSF1A and 14-3-3zeta promoter methylation was also demonstrated in epithelial hyperplasia and intraductal papillomas. By contrast, aberrant methylation of cyclinD2 and p16 was restricted to cancerous epithelium. Increased methylation of the cyclinD2 gene was significantly associated with a higher van Nuys grade. Furthermore, when intraductal and invasive tumor cells were compared, significant quantitative changes in the methylation level were detected primarily within the cyclinD2 gene. These results demonstrate that promoter methylation is an early and frequent event in breast cancer development, but displays great quantitative and gene-specific differences, and changes in a gene-specific manner during tumor progression.

14-3-3 Proteins↗
PubMed2002

Expression of p53 and prognosis in children with malignant gliomas.

BACKGROUND: The prognosis of children with high-grade gliomas is uncertain, even when clinical and histologic findings are considered. We investigated whether mutations in the TP53 gene or the degree of expression of p53 protein in high-grade gliomas is associated with progression-free survival in children with these tumors. METHODS: Paraffin-embedded specimens of malignant gliomas from children treated in the Children's Cancer Group study CCG-945 were assessed by mutational analysis of TP53 (121 specimens) and immunohistochemical analysis of p53 (115 specimens). For mutational studies, areas of tissue that contained malignant glioma were isolated by microdissection, and the DNA was subjected to polymerase-chain-reaction-based amplification and sequencing of TP53 exons 5, 6, 7, and 8. Immunohistochemical analysis was performed with the use of a microwave-enhanced antigen retrieval and an antibody that bound both wild-type and mutant p53. RESULTS: We found a significant association between overexpression of p53 and outcome; this association was independent of histologic features, age, sex, the extent of resection, and tumor location. The rate ( +/- SE) of progression-free survival at five years was 44 +/- 6 percent in the group of 74 patients whose tumors had low levels of expression of p53 and 17 +/- 6 percent in the group of 41 patients whose tumors had overexpression of p53 (P<0.001). A nonsignificant association was observed between mutations in TP53 and outcome. CONCLUSIONS: Overexpression of p53 in malignant gliomas during childhood is strongly associated with an adverse outcome, independently of clinical prognostic factors and histologic findings.

Adolescent↗
PubMed2001

Demonstration of focal p53 expression without genetic alterations in endometriotic lesions.

Their monoclonal origin (as indicated by recent investigations) indicates the neoplastic nature of most endometriotic lesions. p53, a representative tumor suppressor, regulates cell proliferation, and genetic alterations in p53 are involved in carcinogenesis in a wide variety of human cancers. The aim of this study was to examine endometriotic lesions for p53 expression and genetic alterations in p53. An immunohistochemical study revealed that 20% (13/64) of endometriotic lesions showed focal p53 expression in the epithelial cells. Using serial paraffin sections, we employed a microdissection method to extract DNA from the endometriotic tissues that showed p53 expression. No mutations were found in exons 5-8 in p53 by cleavase fragment length polymorphism scanning and polymerase chain reaction-DNA sequencing. Moreover, neither loss of heterozygosity nor microsatellite instability was detected at the microsatellite marker sites of p53. These results suggest that the focal p53 expression recognized in the endometriotic epithelia may be due to overproduction of wild-type p53 protein.

Adult↗
PubMed2000

Novel polymerase chain reaction approach for full-coding p53 mutation detection in microdissected archival tumors.

Evidence suggests that up to 25% of p53 mutations are outside of exons 5-8 and that insertions, deletions, and polymorphic sites in the p53 gene may play a significant role in the process of carcinogenesis. A novel polymerase chain reaction (PCR) approach for the analysis of the entire p53 coding and splice site regions from microdissected, formalin-fixed, paraffin-embedded tumor tissues has been developed which allows multiple genetic analyses to be performed from one primary amplification reaction. The method was initially evaluated using well-characterized cell lines. In addition to confirming the published p53 mutations for HT29, Molt 4, A431, and HN5, a 16 base pair (bp) duplication within intron 3 was detected in both the A431 and HT29 cell lines. Analysis of archival samples of ovarian cancer identified the same 16-bp duplication and coding region variations. In all samples, using GenBank submission U94788 as a reference, a C-insertion was detected at nucleotide positions 11818 and 11874 within intron 2. At nucleotide position 14168, within intron 7, a T-to-G base change was found. This novel PCR approach has the potential to reduce the amount of clinical material required by up to 95%, thus facilitating retrospective studies on archival tumor collections. Furthermore, a wider analysis of the p53 gene, including splice sites and intronic regions, may yield additional information regarding cancer predisposition, response to therapy, and progression.

Base Sequence↗
PubMed1975

Is the cyclic AMP in psoriatic epidermis low?

A deficiency of epidermal cyclic adenosine 3', 5'-monophosphate (cyclic AMP) has been implicated as the cause of the incomplete differentiation, increased mitosis and increased glycogen concentration which characterize the psoriatic lesion. This communication contains our data on the epidermal concentration of cyclic AMP in the lesional and 'normal' (non-involved) skin of patients with psoriasis. In these studies we have introduced the following improvement in methodology: (1) Local ischaemia in the biopsy specimens was prevented by not giving any injections prior to removal of the tissues and by freezing the tissues prior to removal. (2) The epidermis was microdissected from the dermis prior to cyclic AMP assay as as to give as pure an epidermal specimen as possible. Epidermal cyclic AMP was found to be 20-25% higher in the skin lesion than in the uninvolved skin when compared on a dry weight or protein basis but essentially when compared on the basis of DNA content. Our conclusion is that the cyclic AMP level in the psoriatic lesion is not lower than that in the 'normal' skin and thus these characteristics in psoriatic lesions cannot be related simply to a cyclic AMP deficiency.

Adult↗
PubMedDate not supplied

Gene expression patterns in advanced human cervical cancer.

The purpose of this study was to evaluate gene expression patterns in human cervical tumors by extent of lymph node metastases at diagnosis. Pretreatment whole-body fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging was performed in eight patients with invasive squamous cell carcinoma of the cervix to evaluate the extent of lymph nodes metastases. Pretreatment tumor tissue samples were subjected to laser-capture microdissection, and isolated RNA was linearly amplified and hybridized to Affymetrix Human U95A GeneChip microarrays. Molecular FDG-PET imaging revealed that three patients had lymph node involvement in the supraclavicular region and five patients did not. Microarray data were segregated into two groups based on the extent of regional lymph node involvement. Supervised clustering analysis identified 75 of about 12,000 gene transcripts represented on the array whose average expression was at least threefold different. We identified 12 of the 75 transcripts that demonstrated a statistically significant difference in expression between the two patient groups (P < 0.05). Five transcripts were upregulated and seven downregulated. Both overall and cause-specific survivals were different between these two patient groups (P= 0.006). This limited data set identified candidate biomarkers of extent of lymph node metastases that correlated with poor survival outcome.

Adult↗
PubMed2004

Somatic mutations and altered expression of the candidate tumor suppressors CSNK1 epsilon, DLG1, and EDD/hHYD in mammary ductal carcinoma.

We report somatic mutations in three genes (CSNK1 epsilon, encoding the Ser/Thr kinase casein kinase I epsilon; DLG1, encoding a membrane-associated putative scaffolding protein; and EDD/hHYD, encoding a progestin induced putative ubiquitin-protein ligase) in mammary ductal carcinoma. These genes were suspected of playing a role in cancer because loss-of-function mutations in their Drosophila homologues cause excess tissue growth. Using DNA from 82 laser-microdissected tumor samples, followed by microsatellite analysis, denaturing HPLC and direct sequencing, we found multiple somatic point mutations in all three genes, and these mutations showed significant association with loss of heterozygosity of closely linked polymorphic microsatellite markers. For CSNK1 epsilon and DLG1, most of the mutations affected highly conserved residues, some were found repetitively in different patients, and no synonymous mutations were found, indicating that the observed mutations were selected in tumors and may be functionally significant. Immunohistochemical reactivity of each protein was reduced in poorly differentiated tumors, and there was a positive association between altered protein reactivity, loss of heterozygosity, and somatic mutations. There was a statistically significant association of hDlg staining with p53 and Ki67 reactivity, whereas CSK1 epsilon and EDD/hHYD staining levels were associated with progesterone receptor status. The results provide strong indications for a role of all three genes in mammary ductal carcinoma. They also justify additional studies of the functional significance of the changes, as well as a search for additional changes in these and other genes identified from studies on model systems.

Adaptor Proteins, Signal Transducing↗
PubMed1994

[Micromethods for the determination of metabolic characteristics in individual nephron segments].

Since a single nephron is a functional unit of the kidney, individual microdissected segments from the nephron would be ideal tissue samples for investigations on renal pharmacology. Several micromethods have enabled researchers to analyze the biochemical and pharmacological characteristics of these nephron segments. Miniaturized cuvettes containing microliter volumes of samples can be applied for general procedures of photometry like Lowry's protein determination. Fluorometry becomes a more sensitive method when enzymatic cycling systems of NAD/NADH or NADP/NADPH are combined, which have been used for assays of enzyme activities or substrate contents in minute biological samples having tissue proteins less than 1 microgram. The microchemiluminescence procedure has been successfully utilized for cellular ATP content or oxygen radical generation. Radioimmunoassay can be used to determine endogenous components such as cyclic nucleotides, eicosanoids, etc. Continuous gradient polyacrylamide microgels prepared in 5- to 10-microliters capillaries have made it possible to quantify the intranephron distribution of cytochrome P-450, xanthine oxidase and superoxide dismutase. As an example of the modern techniques, microscopic fluorometry using Fura-2AM has been established to identify agonist-induced cytosolic free calcium transients.

Ammonia↗
PubMed1998

Clonality analysis of cervical cancer on microdissected archival materials by PCR-based X-chromosome inactivation approach.

Clonality of invasive human cervical cancer was assessed in microdissected archival formaldehyde-fixed, paraffin-embedded tissues by PCR-based analysis of X-chromosome inactivation of the androgen receptor gene. In 18 informative cases, cancers from 12 cases including 2 early-invasive cancers were scored as monoclonal. Among them, 8 cases had the combination of random X-chromosome inactivation in normal cervical tissue and non-random in the cancer and in other 4 cases normal and cancer tissue were both non-random but had discordant X-chromosome inactivation. Six cases showed that the non-random inactivation affected the same allele in cancer and normal tissue and thus were considered to be inconclusive. The results suggest the monoclonal origin of cervical cancer and indicate that genetic events are critical in transition of pre-malignant epithelia to invasive cancer in cervical carcinogenesis. Finding of monoclonal early invasive cancer also argues that monoclonality of human tumors is not a late event due to clonal competition or selection. X-chromosome inactivation patterns in normal cervical epithelia and tissues were analyzed in 21 informative cases. When a mixture of normal stroma and epithelium was analyzed, 38% (8/21) of cases showed non-random inactivation pattern, whereas using pure epithelium it was 64% (11/17). The X-chromosome inactivation pattern between mixed epithelium/stroma and matched epithelium differed in 2/8 cases. These results point to a certain amount of overlooked source of error in X-inactivation-based tumor clonality analysis in which peripheral blood monocytes were chosen as control and strongly recommend that control tissues which share close histological origin with analyzed tumors should be selected in any clonality study of human neoplasm. Post-embryological mechanisms of clonal patch in normal cervical epithelia are also discussed.

Carcinoma, Squamous Cell↗
PubMed2003

Molecular evidence supporting the neoplastic nature of some epidermoid cysts of the testis.

CONTEXT: Loss of heterozygosity (LOH) on chromosomes 9p and 12q is common in germ cell tumors of the testis. Loss of heterozygosity of 17p13 has also been demonstrated in germ cell tumors. The incidence of LOH in epidermoid cysts, a possible special form of teratoma, has not been previously determined. OBJECTIVE: To determine the frequency of LOH in epidermoid cysts. DESIGN: Eight testicular epidermoid cysts and surrounding parenchyma were microdissected from formalin-fixed, paraffin-embedded tissue, and the genomic DNA was extracted using proteinase K. Polymerase chain reaction analysis targeted regions on chromosome 9p21 (D9S177 and D9S161 loci), chromosome 12q22 (D12S1051 locus), and chromosome 17p13 (TP53 locus). Gel electrophoresis followed by autoradiography was used to detect LOH. RESULTS: All 8 of the epidermoid cysts were informative at a minimum of 1 of 4 loci. Three demonstrated LOH. In 2 tumors, LOH occurred on chromosome 9, and the third tumor demonstrated LOH on chromosome 12. Loss of heterozygosity on chromosome 17p13 was not present in any of the tumors. CONCLUSIONS: Epidermoid cysts harbor allelic loss at some of the same loci identified in malignant testicular germ cell tumors. Our findings support that some examples of epidermoid cysts are neoplastic, although their low frequency of LOH also supports that they are genetically different from malignant germ cell tumors.

Chromosomes, Human, Pair 12↗
PubMed2000

High frequency of clonally related tumors in cases of multiple synchronous lung cancers as revealed by molecular diagnosis.

In patients with multiple synchronous lung tumors, discrimination of multicentric lung cancers from intrapulmonary metastasis is important for treatment decision, but this is sometimes difficult. The aim of this study was to retrospectively distinguish multicentric lung cancers from intrapulmonary metastases in 14 such cases by loss of heterozygosity (LOH) and p53 mutational status. DNA was extracted from microdissected tumor cells in paraffin-embedded archival tissue, and 3p14.2, 3p21, 3p25, 9p21, and 18q21.1 were investigated for LOH. Exons 5-8 of the p53 gene were examined for mutations by the PCR, followed by single-strand conformation polymorphism analysis and DNA sequencing. For cases with the same LOH pattern, we calculated a clonality index, the probability of the given LOH pattern when these tumors were hypothesized to be independent in origin. Eleven of 14 cases (79%) were thus diagnosed as having pulmonary metastasis and only one case as having genuinely multicentric lung cancers. Two cases presented difficulty in diagnosis. In several cases, the LOH patterns conflicted with p53 mutation patterns, suggesting that clonal evolution is directly affected by certain genetic changes. The combination of p53 with LOH helped increase both the sensitivity and specificity of the assay.

Adult↗
PubMed2002

Dominance of functional androgen receptor allele with longer CAG repeat in hepatitis B virus-related female hepatocarcinogenesis.

The CAG polymorphism in exon 1 of the androgen receptor (AR) gene has been shown associated with the development of human male hepatocellular carcinoma (HCC) with the shorter AR alleles conferring a higher risk. However, the significance of AR-CAG repeats in female hepatocarcinogenesis remains to be addressed. In this study, seventy-six pairs of female HCCs and corresponding nontumorous tissues were collected, and 180 cirrhotic nodules were microdissected from 7 cirrhotic livers. The clonality status, functional AR alleles, and CAG repeat number of each sample were determined by AR methylation analysis. In a total of 44 monoclonal HCCs, the mean of CAG repeats in the active alleles was significantly longer than that in the inactive alleles (22.0 +/- 2.8 versus 20.7 +/- 3.6; P = 0.047). When we divided HCCs into hepatitis B virus-positive [HBV(+)] and HBV(-) subgroups, the long AR allele dominance was found only in HBV(+) ones (P = 0.006 versus P = 0.923). Notably, the preference of long CAG repeat has also been found in the 100 monoclonal nodules (P = 0.013). For comparison of monoclonal nodules obtained from the same individual, a dominant long AR allele was found in 6 patients. The proportion of monoclonal cirrhotic nodules and HCCs expressing longer AR allele, 69 and 68%, are both significantly higher than 50%, the assumed value in normal liver (P < 0.001 for cirrhotic nodules and P = 0.005 for HCC). The dominance is again only prominent in HBV-infected HCCs [85% for HBV(+) HCC; P < 0.001 but 54% for HBV(-) HCC; P = 0.27]. The results indicated that in female hepatocarcinogenesis, hepatocytes expressing the longer AR allele seem to be favorably selected for autonomous growth and transformation, especially in synergy with HBV infection.

Adult↗
PubMedDate not supplied

P53 mutation but not p16/MTS1 mutation occurs in intraductal papillary mucinous tumors of the pancreas.

BACKGROUND/AIMS: Intraductal papillary mucinous tumors of the pancreas are rare lesions, which typically show a benign clinical course. However, some of these tumors have a malignant nature and grow in an invasive manner. The purpose of the study was to determine the prevalence of p53-, p16/MTS1- and K-ras mutations in benign and malignant intraductal papillary mucinous tumors with intent to value their importance for tumor progression. METHODOLOGY: Thirteen different archival tumor specimens were obtained at the Department of Pathology, University of Ulm. Three cases showed an invasive component of the tumor. Genomic DNA was extracted after laser capture microdissection of tumor cells from paraffin-embedded tissue sections. The corresponding sequences of p53 (exon 5, 6, 7, 8) and p16/MTS1 (exon 2) were amplified by polymerase chain reaction and subjected to single strand conformation polymorphism analysis. Codon 12 of K-ras was analyzed by the enrichment polymerase chain reaction-restriction fragment length polymorphism method. Positive samples were further investigated by sequencing. RESULTS: K-ras mutations occurred in benign and malignant intraductal papillary mucinous tumors (4/13), whereas an alteration of the coding p53 gene sequence could only be detected in the intraductal and invasive component of one malignant tumor. None of the tissue specimens revealed mutations in exon 2 of p16/MTS1. CONCLUSIONS: In contrast to K-ras mutations, alterations in the p53 gene may characterize ductal papillary mucinous carcinomas, which could be of major interest for their early diagnosis. The lack of mutations in the p16/MTS1 gene suggests that other genes may be involved in the formation of intraductal papillary mucinous neoplasias.

Biomarkers, Tumor↗