Genetic pathways in the evolution of breast ductal carcinoma in situ

The patterns of allelic loss in 28 cases of pure ductal carcinoma in situ (DCIS) and 25 cases of DCIS associated with invasive ductal carcinoma (IDC) were compared, in order to define whether pure DCIS represented an earlier stage than DCIS associated with IDC in the progression of breast carcinoma. To this aim, the polymerase chain reaction (PCR) was performed on microdissected normal and neoplastic breast tissue, formalin-fixed and paraffin-embedded. Fifteen microsatellite markers were examined, on chromosomes 1p, 3p, 7q, 11q, 12p, 13q, 16q and 17q, mostly focused on regions altered in breast cancer. Loss of heterozygosity (LOH) was greater in pure DCIS than in the DCIS component associated with IDC for 11 out of 15 markers. The difference was statistically significant for D13S260 and D17S800 (p=0.008 and p=0.01, respectively). DCIS associated with IDC showed a lesser degree of alteration than the synchronous IDC component for ten out of 15 markers. In contrast, LOH at D11S1816 and D16S318 was lower in pure DCIS than in DCIS associated with IDC and even greater in the IDC component. These results confirm that DCIS is a possible but not an obligate precursor of invasive breast cancer and suggest that pure DCIS and DCIS associated with IDC may be genetically distinct. The evolution from DCIS to IDC may follow multiple pathways and not a linear model.     

乳腺浸润性导管癌微卫星不稳定性

目的 探讨乳腺浸润性导管癌的微卫星不稳定(MSI)性及其与临床病理资料的关系。方法 选取10个微卫星位点，从石蜡包埋的存档标本中选取34例肿瘤组织和其对应的自身正常对照组织，提取DNA后用PCR扩增，6％聚丙稀酰胺凝胶电泳，银染显色后进行微卫星不稳定性分析。用免疫组化S-P法观察p53、c-erbB-2、PR、ER在乳腺癌中表达情况。结果 在34例乳腺浸润性导管癌中有9例(26．47％)至少1个位点出现MSI。MSI和病人年龄、肿瘤大小、病理分级、淋巴结转移、p53、c-erbB-2之间没有明显的相关性。但ER和PR阴性的病例出现MSI的比例远远高于ER和PR阳性病例。结论在乳腺癌的发生、发展过程中出现MSI,并可能和ER、PR的表达降低有关。     

乳腺癌和导管增生病变与1p染色体不稳定的关系

目的检测乳腺普通型导管增生(usual dutal hyperplasia,UDH)、乳腺不典型增生(atypical dutal hyperplasia,ADH)、乳腺导管原位癌(dutal carcinoma in situ,DCIS)及乳腺浸润性导管癌(invasive dutal carcinoma,IDC)中染色体1p微卫星杂合性缺失(loss of heterozygosity,LOH)/微卫星不稳定(microsatellite instability,MSI)的改变规律,探讨乳腺导管增生病变进展为IDC的遗传学改变特征。方法应用PCR法检测20例UDH、7例ADH、25例DCIS、25例IDC石蜡包埋组织,8%尿素变性聚丙烯酰胺凝胶电泳后银染检测染色体1p区间微卫星位点D1S193、D1S463、D1S2881、D1S2885、D1S234、D1S252的LOH/MSI。结果染色体1p的每个位点均发生LOH/MSI,其发生的频率UDH为55.0%、ADH为42.9%、DCIS为64.0%、IDC为72.0%,各组间差异无显著性(P0.05);微卫星位点D1S193、D1S2881、D1S2885、D1S252、D1S234在各组中LOH/MSI的频率差异均无显著性(P0.05)。D1S463的频率在UDH组为5.0%、ADH组为0、DCIS组为45.0%、IDC组为40.0%,其中UDH组与ADH组明显低于DCIS组、IDC组(P0.008)。结论 1p染色体遗传学不稳定是乳腺癌发生的早期事件,D1S463位点的改变可能在乳腺导管增生性病变进展为乳腺癌中起关键作用。     

Detection of loss of heterozygosity of p53 gene in paraffin-embedded breast cancers by non-isotopic PCR–SSCP

A rapid non-isotopic PCR-SSCP (polymerase chain reaction-single-stranded conformation polymorphism) method was developed in this study to detect polymorphism and loss of heterozygosity (LOH) of p53 in formalin-fixed and paraffin-embedded samples of normal breast tissue and of breast cancer. p53 expression was also examined by immunohistochemistry. In 35 paired samples, heterozygosity in exon 4 of p53 was detected in 17 cases (49 per cent) and LOH of the p53 gene in breast cancer tissues was observed in 7 out of 15 informative cases (47 per cent). The correlation of LOH of p53 with positive p53 immunostaining did not reach statistical significance, but all immunostaining-positive tumours among informative cases had LOH of p53. The results support the hypothesis that in most cases the allelic deletion of p53 may uncover the ‘recessive mutation’ in the remaining allele. However, LOH of p53 was more frequent than positive immunostaining and was significantly associated with poor differentiation of breast cancer (P<0·05). The results suggest that the allelic deletion of p53 may also contribute to the development and progression of breast cancer by reducing the amount of normal p53 protein. These results show that non-isotopic PCR-SSCP is a simple, fast, and effective method for detecting polymorphism and LOH of the p53 gene, which is especially useful for retrospective studies.     

Retinoblastoma and p53 gene product expression in breast carcinoma: Immunohistochemical analysis and clinicopathologic correlation

We examined 100 breast cancers for retinoblastoma (Rb) and p53 protein expression by immunohistochemistry using the PMG3.245 and PAb 1801 antibodies. We assessed percentages of reactive cells and their intensity, as well as staining patterns. The results were correlated with neu protein reactivity and a panel of variables, including age, tumor size and type, nuclear grade, estrogen receptor/progesterone receptor content, and lymph node status. Retinoblastoma protein negativity, either partial or complete, was noted in 47% of cases. Surprisingly, a relatively stronger Rb reaction was seen in some high nuclear grade tumors. p53 positivity was found in 23% of cases and was a significant predictor of Rb loss. p53 also was correlated with poorly differentiated (nuclear grade III) neoplasms and neu expression but not with negative ER status. Tissue distribution profiles for Rb-negative and p53-positive cells were variable in this series, with both uniform and heterogeneous patterns observed. This suggests that Rb and p53 alterations may represent early or late events in transformation. Our findings further implicate Rb and p53 derangements in mammary oncogenesis.     

DNA analysis at p53 locus in adenoid cystic carcinoma: Comparison of molecular study and p53 immunostaining

Abnormalities of the p53 tumor suppressor gene were investigated in 22 foci from 14 adenoid cystic carcinomas (ACC) by polymerase chain reaction (PCR)-based assays for dinucleotide (CA)_n and pentanucleotide (AAAAT)_n repeat polymorphisms and by immunohistochemical staining for oncoprotein expression. Adenoid cystic carcinomas were divided into lower grade (tubular and cribriform) subtypes and higher grade (trabecular and solid) subtypes. Histologically identified tumor cells were precisely microdissected from archival microslides and were used for molecular analysis. The overall frequency of p53 gene mutations detected by PCR-loss-of-heterozygosity (LOH) analysis was 57% and was higher than the frequency of overexpression of p53 oncoprotein detected by immunostaining (43%). In the molecular analysis of individual histological subtype foci, the number of foci with p53 gene mutation was slgnificantly greater in the higher grade subtype foci than in the lower grade subtype foci and was greatest in solid-type foci (100%). In all six tumors in which histologically different foci were present In the Same tumors, mutations of the p53 gene were detected. When tumor heterogeneity of the p53 gene was present among different histological foci in the same tumors, the mutations were always detected in the higher grade foci. When lower and higher grade foci were present in the same tumors, the identical mutations detected In the lower grade foci were present in the corresponding higher grade foci. These findings indicate that abnormaliies of the p53 gene are involved in carcinogenesis and/or progression of this tumor and, furthermore, suggest that molecular analyses of ACC may provide information of prognostic importance.     

Alteration of the p53 gene of lung carcinomas with sarcomatous transformation (spindle cell carcinoma): analysis of four cases

Lung carcinoma with sarcomatous transformation (LCST) is highly aggressive and characterized by local invasion and/or distant metastasis, which leads to a shorter survival than ordinary lung carcinomas. Therefore, to elucidate whether the malignant potential of the spindle cell element in LCST is associated with the alteration of the p53 gene, four cases were examined by analyses of overexpression of the p53 oncoprotein, mutation of the p53 gene and loss-of-heterozygosity (LOH) at chromosome 17p. In two cases overexpression of the p53 oncoprotein of the spindle cell component showed a higher degree of staining than that of the carcinoma component; LOH was identified in both carcinoma and sarcomatous components in one case, while in contrast, another case showed LOH in the sarcomatous component only. Mutations were clearly detected in two cases; one showed a CTT to CGT transversion in codon 194 of exon 6 in both components, whereas the other showed a CTG to CAG transversion in codon 265 of exon 8 in the sarcomatous component only. On the basis of these observations, it suggested that the sarcomatous component shows a higher frequency of p53 gene abnormalities in comparison to the carcinoma component. These results also suggested that the acquisition of malignant potential in the sarcomatous component, or the morphological alteration of carcinoma cells, is correlated with abnormalities associated with the p53 gene.     

Myoepithelial carcinoma arising in an adenomyoepithelioma of the breast: case report with immunohistochemical and mutational analysis

Adenomyoepithelioma (AME) of the breast is an uncommon tumor characterized by biphasic proliferation of both epithelial and myoepithelial cells. In rare instances, the epithelial, the myoepithelial or both components of an AME may become malignant. Described herein is the case of a 69-year-old woman who presented with myoepithelial carcinoma of the breast in an AME. Malignancy of myoepithelial component (MEC) was evidenced by the presence of cytological atypia, high mitotic rate, necrosis and local invasion. Immunohistochemical study demonstrated strong expression of P53 and phosphorylated extracellular signal-regulated kinase 1/2 in MEC. Laser capture microdissection technique and mutational analysis further revealed point mutation of the p53 gene (T-->G transversion at codon 270) in this population, but not in glandular epithelial cells or adjacent normal ductal epithelium. No mutations in exons 1 and 2 of the K-, H-, and N-ras genes were identified in any of the neoplastic component. To the authors' knowledge this is the first report of a mutation in the p53 gene in a malignant AME of the breast.     

p53 overexpression and mutation in metaplastic carcinoma of the breast: genetic evidence for a monoclonal origin of both the carcinomatous and the heterogeneous sarcomatous components

Metaplastic carcinoma of the breast (MCB) is characterized by the biphasic presence of both a carcinomatous component (CC) and heterogeneous sarcomatous components (HSCs). Although an epithelial or myoepithelial origin of the HSCs has been suggested, molecular evidence for a common origin for the CC and HSCs is limited and the mechanism underlying the sarcomatous or metaplastic change is unknown. The present study investigated the frequency and nature of p53 expression and mutation in 11 biphasic and three monophasic MCBs by immunohistochemistry and either needle-assisted or laser-capture microdissection, followed by PCR and direct sequencing. In all 11 biphasic MBCs, staining for p53 was concordant in the CC and HSCs (8/11 positive and 3/11 negative), consistent with a monoclonal origin of both components. Significantly, whenever a component of carcinoma in situ was present (5/11), the p53 staining was always concordant with that in the CC and HSCs. Screening of the 14 cases for p53 mutation identified four mutants, each in a single case of biphasic MCB with concordant p53 overexpression. Both the CC and each of the HSCs revealed identical p53 mutation in all four cases; in addition, one of the four cases also had an in situ component and the same mutant was found simultaneously in the in situ, invasive, and sarcomatous components. The concordant pattern of p53 alteration (overexpression or mutation) implies that early p53 mutation, occurring prior to invasion, was maintained throughout tumour progression and metaplastic change. The findings therefore support a monoclonal histogenesis of the various components, but are neutral regarding the role of p53 alteration in the development of metaplastic change in MCBs.     

Differential loss of heterozygosity profile on chromosome 3p in ductal and lobular breast carcinomas

The 2 main histologic types of infiltrating breast cancer, invasive lobular and invasive ductal carcinoma, are morphologically and clinically distinct. Studies revealed that different patterns of gene expression and loss of heterozygosity can also distinguish these 2 subtypes. A whole-genome study using single nucleotide polymorphism array found a significantly higher frequency of loss of heterozygosity on 3p in invasive ductal carcinoma when compared with invasive lobular carcinoma. In this study, we performed a loss of heterozygosity analysis of the 3p chromosome region in ductal and lobular breast tumors. Seven microsatellite markers were evaluated in a series of 136 sporadic breast cancer cases (118 invasive ductal carcinoma and 18 invasive lobular carcinoma) and correlated with clinical-histopathologic parameters from the patients. A significantly higher frequency of loss of heterozygosity was observed in invasive ductal carcinoma (65.3%) when compared with invasive lobular carcinoma (38.9%). When the markers were analyzed separately, loss of heterozygosity at 3 of them, D3S1307 in 3p26.3, D3S1286 in 3p24.3, and D3S1300 in 3p14.2, were significantly more frequent in ductal than in lobular tumors. D3S1307 marker showed the highest frequency of loss of heterozygosity in invasive ductal carcinoma (46.2%), and associations between loss of this marker and loss of estrogen and progesterone receptors were found in these samples. Our results confirm the observations that invasive ductal carcinoma has a higher frequency of loss of heterozygosity events across the 3p region than invasive lobular carcinoma and show that specific losses on 3p26.3, 3p24.3, and 3p14.2 regions are more frequent in ductal than in lobular tumors. We discuss our data in relation to the known tumor suppressor genes that are mapped at the 3p loci investigated and their present relevant roles in breast cancer.     

Over-expression of p53, p21 and Cdc2 in histologically negative surgical margins is correlated with local recurrence of laryngeal squamous cell carcinoma

The aim of this study was to explore the relationship between the expression of p53, p21 and Cdc2 in the early laryngeal cancer with negative pathological margins and its local recurrence. During 2004-2010, a total of 85 patients with early laryngeal cancer were selected in Tangshan Union Hospital, Hebei, China, and immunohistochemical method was used to detect the expression of p53, p21 and Cdc2 in the negative pathological margin tissues. All patients were followed up for two years to collect pathological data for evaluating the survival and tumor recurrence. Two years after surgery 14 of 85 patients with laryngeal cancer presented with recurrence (recurrent group), while 71 patients without recurrence (none recurrent group). The positive rate of p53, p21 and Cdc2 protein in laryngeal cancer tissues was 60.0% (51/85), 38.8% (33/85) and 70.6% (60/85), respectively, while that of the three proteins in the cancer adjacent tissues was 36.5% (31/85), 21.2% (18/85) and 29.4% (25/85), respectively. The differentiation and TNM stage of tumor had no correlation with the three proteins. The positive rate of p53 in the surgical margin of the recurrent group and non recurrent group was 71.4% (10/14) and 29.6% (21/71) (P = 0.003), that of p21 was 50.0% (7/14) and 15.5% (11/71), (P = 0.011) and Cdc2 was 57.1% (8/14) and 23.9% (17/71) (P = 0.030), respectively. In conclusion, p53, p21 and Cdc2 may be involved in the occurrence, development and recurrence of laryngeal squamous cell carcinoma. Overexpression of p53, p21 and Cdc2 in the surgical margin of early laryngeal cancer is closely related to local recurrence of tumor.     

Absence of microsatellite instability in breast carcinomas with both p53 and c-erbB-2 alterations

Based on a previous finding that amplification of the c-erbB-2 oncogene and alteration of p53 are strongly associated in most aggressive breast tumours, the present study investigated whether microsatellite instability (MI) might also be associated with this tumour phenotype. Nine polymorphic microsatellite markers, including six dinucleotide, one trinucleotide, and two tetranucleotide repeats, were amplified from paired normal and tumour DNA samples of 15 breast tumours that overexpressed both c-erbB-2 and p53 and of 15 control breast tumours that overexpressed neither protein. All 30 breast tumours analysed exhibited a replication error-negative phenotype, with only one sample showing MI in one of the nine loci. This suggests that the genetic events underlying MI, which are critical in colorectal and gastric tumours, are not involved in the pathogenesis of c-erbB-2/p53 double-altered breast tumours and do not play a central role in breast tumour formation. Copyright © 1999 John Wiley & Sons, Ltd.     

Improved detection of loss of heterozygosity at retinoblastoma gene locus in human breast carcinoma

Loss of heterozygosity (LOH) at the retinoblastoma (Rb) gene locus was investigated in 33 breast carcinomas by polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) analysis after tumor cell enrichment by cell sorting. The efficacy of cell sorting was evaluated by comparing the results of PCR-SSCP with and without cell sorting. Ten of 17 (59%) informative cases showed LOH at this locus by cell sorting combined with PCR-SSCP, although LOH was detectable in six (35%) cases without cell sorting. Flow cytometry and histologic examination revealed that this underestimation may occur when the tumor cell population is less than 50% in the specimens analyzed. It is concluded that LOH of the Rb gene occurs more frequently in human breast carcinoma than previously thought, and thus may contribute significantly to the development and/or progression of this tumor.     

Deletion mapping of chromosome 13q in head and neck squamous cell carcinoma in Indian patients: correlation with prognosis of the tumour

Deletions in chromosome (chr.) 13q occur frequently in head and neck squamous cell carcinoma (HNSCC). Previous studies failed to identify common deleted regions in chr.13q, though several candidate tumour suppressor genes (TSGs) loci, e.g. BRCA2, RB1 and BRCAX have been localized in this chromosome, as well as no prognostic significance of the deletion has been reported. Thus, in the present study, deletion mapping of chr. 13q has been done in 55 primary HNSCC samples of Indian patients using 11 highly polymorphic microsatellite markers of which three were intragenic to BRCA2 gene, one intragenic to RB1 gene and another from BRCAX locus. The deletion in chr.13q was significantly associated with progression of HNSCC. High frequencies (27-39%) of loss of heterozygosity were found in 13q13.1 (BRCA2), 13q14.2 (RB1), 13q21.2-22.1 (BRCAX) and 13q31.1 regions. Deletions in the BRCA2 and RB1 regions were significantly correlated. The four highly deleted regions were associated with clinical stage and histological grades of the tumour as well as poor patient outcome. Deletion in the 13q31.1 region was only found to be associated with HPV infection. High frequencies (11-23%) of microsatellite size alteration (MA) were seen to overlap with the highly deleted regions. Forty per cent of the samples showed rare biallelic alteration whereas loss of normal copy of chromosome 13q was seen in five tumours. Thus, it seems that the putative TSGs located in the BRCAX and 13q31.1 regions as well as the BRCA2 and RB1 genes may have some cumulative effect in progression and poor prognosis of HNSCC. Significant association between deletion in BRCA2 and RB1 gene loci may indicate functional relationship between the genes in this tumour progression.     

Intraepidermal cells of Paget's carcinoma of the breast can be genetically different from those of the underlying carcinoma

Paget's carcinoma (PC) of the breast is characterized by neoplastic cells of "glandular" type located within the epidermis of the nipple-areolar complex, often associated with an underlying ductal carcinoma, either in situ or invasive. At present the origin of PC cells is controversial, although there is a widespread opinion that PC cells are "foreign" elements to the epidermis resulting from an epidermotropic migration of neoplastic elements from an underlying ductal carcinoma. An alternative view is that some cases result from neoplastic transformation of preexisting, innocent intraepidermal clear cells of the nipple-areolar complex (Toker cells) that migrate from nonneoplastic ducts. Consequently, 10 cases were studied using methods for clonality (ie, loss of heterozygosity and mitochondrial DNA displacement loop sequence analysis). Microdissection of intraepidermal neoplastic cells and of cells from underlying duct carcinomas and metastases was performed. In no fewer than 2 cases, PC cells were genetically different from underlying lesions, which showed consistent homology among themselves. Therefore, it is suggested that the rule of epidermotropism by neoplastic cells from an underlying carcinoma is not applicable to all cases, and that in some cases PC cells might be the result of neoplastic transformation of preexisting intraepidermal nonneoplastic cells. Consequently, the underlying tumors are coincidental neoplastic lesions (collision tumors).     

Loss of heterozygosity in ductal carcinoma in situ of the breast

Loss of heterozygosity (LOH) at loci reported to show allele loss in invasive breast cancers was examined in ductal in situ carcinomas of the breast using polymorphic short tandem repeats and the polymerase chain reaction (PCR). LOH was detected at all loci examined in at least 11 per cent of the samples examined. The proportion of cases of in situ carcinoma showing LOH at these loci was similar to that previously reported in invasive cancers. Cases of pure in situ cancer without an invasive component exhibited an overall lower frequency of allele loss. LOH at more than one locus was observed in some intraductal cancers. In a small number of cases, LOH was present in the invasive but not in the intraductal component of the tumour, suggesting that mutation at the locus concerned was associated with development of invasive behaviour.     

长链非编码RNA-PURPL对肝细胞癌增殖和凋亡的影响及其机制

目的 探讨长链非编码RNA-PURPL对肝癌细胞的调控.方法 采用siRNA干扰肝癌细胞系中lnc RNA-PURPL的表达,分别用细胞计数法检测siRNA干扰后的细胞增殖情况、用流式细胞术检测siRNA干扰后的细胞凋亡率、Western blot法检测与凋亡相关的一些蛋白探究作用机制、ELISA法检测干扰后细胞分泌的...     

Netrin‐4 is upregulated in breast carcinoma effusions compared to corresponding solid tumors

We recently identified overexpression of the NTN4 gene in breast carcinoma effusions compared to primary carcinomas using gene‐expression arrays. The objective of this study was to validate this finding at protein level and analyze the clinical role of Netrin‐4 in breast carcinoma effusions. We additionally studied Netrin‐4 expression and its clinical relevance in Müllerian (ovarian, peritoneal, and tubal) carcinoma effusions. Sections from 82 breast carcinomas (53 effusions and 29 solid tumors) and 57 Müllerian carcinoma effusions were stained for Netrin‐4 using immunohistochemistry. Immunoreactivity was scored in carcinoma cells and analyzed for association with clinicopathologic parameters, including survival. In breast carcinoma, expression of Netrin‐4 was detected in carcinoma cells in 30/53 (57%) effusions compared to 3/29 (10%) solid tumors (P < 0.001). Netrin‐4 was further expressed in 31/57 (54%) Müllerian carcinoma effusions. No association was found between Netrin‐4 expression in breast or Müllerian carcinoma effusions and clinicopathologic parameters, including survival. Our data provide validation on protein level of upregulated Netrin‐4 expression in breast carcinoma effusions. The frequent expression of Netrin‐4 in Müllerian carcinoma effusions suggests a biological role for this molecule in metastases from gynecological malignancies. Netrin‐4 expression in effusions does not appear to be a predictor of disease outcome. Diagn. Cytopathol. 2011. © 2010 Wiley‐Liss, Inc.     

p53基因第7外显子点突变与乳腺癌的关系

目的：研究ｐ５３基因点突变与乳腺癌发生发展关系。该当：应用多聚酶链反应－限制性片段长度多态性（ＰＣＲ－ＲＦＬＰ）检测７５例人乳腺癌标本ｐ５３基因第７外显子内２４８，２４９位密码子的点突变，结果：７５例乳腺癌标本ｐ５３基因第７外显子全长序列ＣＲ扩增产物经限制性内切酶ＭｓｐＩ酶切后，发现２例为突变型，用ＨａｅⅡ酶切后未发现有突变，结论：上述结果揭示ｐ５３基因第７外显子内２４８位密码子的突变为乳腺癌ｐ５     

Analysis of microsatellite alterations in gastric carcinoma using the crypt isolation technique

The crypt isolation technique was used to analyse loss of heterozygosity (LOH) and microsatellite instability (MSI) in gastric carcinomas (36 intestinal type, 17 solid type, and 23 diffuse type) using a polymerase chain reaction assay. Increased LOH frequencies and fractional allelic losses (FAL) were observed in samples prepared using the crypt isolation technique compared with those isolated by the conventional method. A significant increase in LOH was found at several chromosomal loci, and significant differences in FAL were found in patients with intestinal- and solid-type tumours. There was no difference in the frequency of MSI using either technique. In samples prepared by the crypt isolation technique, significant allelic losses (> or =50%) were observed at most loci tested in intestinal- and solid-type tumours, but not in diffuse-type tumours. Significant losses of some of these loci are novel findings for gastric cancer. FAL values were significantly higher in intestinal- and solid-type tumours than in diffuse-type tumours. MSI-high was observed in intestinal- (17%) and solid-type (12%) tumours. The results suggest that the crypt isolation technique is useful for accurate allelic loss analysis in gastric carcinoma and that LOH and MSI are more common in intestinal- and solid-type tumours than in diffuse-type tumors.