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Biomedical subjects

F H Sarkar

Publications and source records attributed to F H Sarkar.

At least 91 records · Page 5Linked to original sources
PubMed1995

Biologic and clinical significance of basic fibroblast growth factor immunostaining in breast carcinoma.

Acetone-fixed cryostat sections of 79 breast carcinomas were immunostained with antibodies to basic fibroblast growth factor (bFGF) and urokinase-type plasminogen activator (uPA). Staining intensity was then compared with microvessel density assessed by manually counting vascular spaces highlighted by immunostaining vascular basal lamina (Type IV) collagen. Extensive (2+) bFGF immunoreactivity was present in neoplastic cells of 30 tumors (38%) and in host-derived stromal cells of 29 cases (37%). Disease recurrence correlated with bFGF staining: 0 to 1+ stromal staining, 30% recurred versus 2+ stromal staining, 73% recurred (P = 0.001) (54-mo median follow-up). Neither stromal nor epithelial bFGF staining correlated significantly with microvessel count; however, there was a statistically significant association between stromal cell bFGF staining and uPA staining of peritumor host cells: absent bFGF--0% 2+ uPA versus weak bFGF--9% 2+ uPA versus 2+ bFGF--29% uPA (P = 0.01). We conclude that elevated expression of bFGF in breast carcinomas is associated with aggressive clinical behavior. Its biologic significance, however, appears more closely related to extracellular matrix remodeling than to induction of prominent neovascularization per se.

Breast Neoplasms↗
PubMed1994

Enhanced expression of tissue inhibitor of metalloproteinase-2 (TIMP-2) in the stroma of breast carcinomas correlates with tumor recurrence.

The 72-kDa (MMP-2, gelatinase A) and the 92-kDa (MMP-9, gelatinase B) matrix metalloproteinases have been associated with tumor cell invasion and metastasis. Immunohistological staining of MMP-2 and MMP-9, basal lamina collagen IV and TIMP-2 were performed on frozen sections of 83 invasive breast carcinomas. MMP-2 and MMP-9 were associated with neoplastic cell plasma membrane in 72% of cases and exhibited inter-tumoral variability of staining intensity. MMP-2 and MMP-9 staining was not correlated with presence of metastases at time of diagnosis or with disease outcome. TIMP-2 was detected in the peri-tumoral stroma and was present in 87% of cases. Residual benign breast tissue was negative for TIMP-2 staining. Neoplasms with diffuse TIMP-2 staining (24%) recurred significantly more frequently (75% recurred) than cases with focal (42% recurred) or absent (27% recurred) TIMP-2. Presence of collagen IV was negatively correlated with gelatinase staining. We conclude that up-regulation of MMP-2 and MMP-9 expression in breast tumor cells is reciprocally correlated to collagen IV staining. Clinical outcome, however, is more closely related to the presence of TIMP-2 than the corresponding MMPs. Enhanced TIMP-2 expression, therefore, may denote a stromal response to tumor invasion, indicative of aggressive behavior in a subset of breast carcinomas.

Antibodies, Monoclonal↗
PubMed1994

c-erbB-2 promoter-specific DNA-binding protein isolated from human breast cancer tissues displays mitogenic activity.

Amplification and overexpression of the c-erbB-2 gene appears to play a role in the pathogenesis of human breast and other cancers. Frequent amplification (20-30%) of the c-erbB-2 gene was observed in human adenocarcinomas of kidney, pancreas, lung, ovarian, and breast cancer. The gene product is a 185-kDa glycoprotein that has intrinsic tyrosine kinase activity and is believed to be a receptor. Several candidate ligands have been described. In the present study we have identified and purified a novel DNA-binding protein from malignant human breast tissues. The protein binds to a core element (-22 to +9, +1 being the transcription start site) of the c-erbB-2 promoter region in a sequence-specific manner. The affinity-purified protein has the ability to induce DNA synthesis in quiescent NIH/3T3 cells, suggesting that the factor has mitogenic activity. The purified protein induces c-erbB-2 expression on the surface of microinjected NIH/3T3 cells. This DNA-binding protein is a sequence-specific cellular factor that is associated with high level expression of the c-erbB-2 gene and appears to play a role in cell transformation. Understanding the control and expression of this DNA-binding protein may shed light on the mechanism(s) of c-erbB-2 gene regulation and its potential role in the pathogenesis of human adenocarcinomas.

3T3 Cells↗
PubMed1994

Interaction of transforming growth factor-alpha and epidermal growth factor receptor in breast carcinoma. An immunohistologic study.

BACKGROUND: Interaction of transforming growth factor-alpha (TGF-alpha) with its receptor, epidermal growth factor receptor (EGFR), has been implicated as an autoregulatory autocrine mechanism of breast epithelial proliferation. METHODS: To examine the interrelationship and clinical relevance of TGF-alpha and EGFR in breast carcinoma, methanol-fixed cryostat sections from 73 patients were immunostained with monoclonal antibodies to epidermal growth factor (EGF), EGFR, and TGF-alpha. RESULTS: Neither EGFR nor TGF-alpha staining was diagnostic or specific for the detection of malignant neoplastic cells. Both exhibited staining along the basal lamina of most benign ducts and lobules. TGF-alpha staining was observed in neoplastic cells in 41% and in non-neoplastic cells (peritumoral stroma and benign duct/lobular epithelium) in 36% of patients. Staining for EGF and TGF-alpha failed to correlate with node status or grade; however, TGF-alpha negative tumors were more frequently positive for estrogen receptor (ER) (70% versus 14%; P = 0.03). The presence of EGFR correlated with positive lymph node status (P = 0.004), poor differentiation (P = 0.001), and negative ER status (P = 0.0001). EGFR staining was more common in neoplasms which recurred, but this approached significance only in the group with node-negative disease (mean follow-up, 52 months; P = 0.06), and neoplastic cell TGF-alpha correlated with disease recurrence in patients with node-positive disease (no recurrence, -13% positive versus recurrence, -52% positive; P = 0.01). Concurrent TGF-alpha/EGFR staining, present in 18% of tumors, also was predictive of disease recurrence (no recurrence, 3% positive for both versus recurrence, 31% positive for both, P = 0.03). CONCLUSIONS: TGF-alpha is heterogeneously expressed in neoplastic and host-derived components of breast tumors. Concurrent EGFR/TGF-alpha immunostaining may characterize a clinically aggressive subset of breast carcinomas, possibly reflecting autocrine interaction, and conferring growth advantage or metastatic phenotype.

Breast Neoplasms↗
PubMed1994

Prevalence of HPV 16 and 18 DNA sequences in CIN III lesions of adults and adolescents.

Adolescents may be more susceptible to cervical human papillomavirus (HPV) infections and may have more rapid progression of cervical intraepithelial neoplastic (CIN) lesions than adults. We evaluated Papanicolaou (Pap) smears and cervical tissue specimens from a consecutive series of 25 adolescent (age 15-20 yr) and 17 adult (age 35-40 yr) patients with a histologic diagnosis of CIN III. The study patients were all Detroit residents enrolled in a health maintenance organization (HMO) affiliated with Henry Ford Hospital. The cervical tissue specimens were evaluated for HPV 6b/11, HPV 16, and HPV 18 using agarose gel electrophoresis and Southern hybridization following polymerase chain reaction (PCR) DNA amplification. While the small sample size precluded testing for statistical significance, HPV 16 and/or HPV 18 DNA was detected in specimens from 21/25 (84%) adolescents compared to 12/17 (71%) adults (odds ratio [OR] = 2.2; 95% confidence interval [CI] = 0.49-9.74). The relationship between adolescence and HPV infections appears to be stronger for HPV 18 and mixed HPV 16/18 infections (OR = 5.6; 95% CI = 0.7-42.4) than for HPV 16 infections (OR = 1.93; 95% CI = 0.4-8.8). None of the cervical specimens contained HPV 6b/11 DNA. Oral contraceptive (OC) use was associated with HPV infection in patients with CIN III, but there was no association between cigarette smoking and HPV infection. The effect of OC use on the relationship of age and HPV could not be evaluated due to small sample size. The effects of previous sexually transmitted disease (STD) on the relationship of age and HPV were assessed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Analysis of p53 gene mutations in human gliomas by polymerase chain reaction-based single-strand conformation polymorphism and DNA sequencing.

Mutations in the p53 gene have been recognized in brain tumors, and clonal expansion of p53 mutant cells has been shown to be associated with glioma progression. However, studies on the p53 gene have been limited by the need for frozen tissues. We have developed a method utilizing polymerase chain reaction (PCR) for the direct analysis of p53 mutation by single-strand conformation polymorphism (SSCP) and by direct DNA sequencing of the p53 gene using a single 10-microns paraffin-embedded tissue section. We applied this method to screen for p53 gene mutations in exons 5-8 in human gliomas utilizing paraffin-embedded tissues. Twenty paraffin blocks containing tumor were selected from surgical specimens from 17 different adult patients. Tumors included six anaplastic astrocytomas (AAs), nine glioblastomas (GBs), and two mixed malignant gliomas (MMGs). The tissue section on the stained glass slide was used to guide microdissection of an unstained adjacent tissue section to ensure > 90% of the tumor cell population for p53 mutational analysis. Simultaneously, microdissection of the tissue was also carried out to obtain normal tissue from adjacent areas as a control. Mutations in the p53 gene were identified in 3 of 17 (18%) patients by PCR-SSCP analysis and subsequently confirmed by PCR-based DNA sequencing. Mutations in exon 5 resulting in amino acid substitution were found in one thalamic AA (codon 158, CGC > CTT: Arg > Leu) and one cerebral hemispheric GB (codon 151, CCG > CTG: Pro > Leu).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Premalignant lesions of the upper aerodigestive tract: biomarkers of genetic alterations, proliferation, and differentiation.

The normal distribution of cell division in squamous mucosa is in the basal or adjacent suprabasal cell layers. Migration of cells toward the epithelial surface results in cell differentiation, most often expressed by high molecular weight keratin intermediate filaments and components of the cornified envelope, including "involucrin." These latter expressions of terminal differentiation are common in keratinizing dysplasia and invasive squamous cell carcinomas. However, they are less common in the non-keratinizing dysplasias, which fail to express evidence of epithelial maturation. Cell proliferation occurs in or near the basal layer in normal or reactive/reversible hyperplasias. In dysplasia (both keratinizing and non-keratinizing), cell proliferation is observed at all levels of the epithelium. Concomitant with these abnormalities in proliferation and differentiation are nuclear changes characterized by large hyperchromatic nuclei. The enlarged nuclei reflect increased DNA content, as documented by flow cytometry and image analysis techniques. DNA aneuploidy represents a spectrum of genomic alterations reflecting steps toward the progression to invasive carcinoma, which for the most part, have not yet been identified.

Animals↗
PubMed1993

Measurement of cellular proliferation in human prostate by AgNOR, PCNA, and SPF.

Tumor differentiation and proliferative activity are important predictors of biological behavior. While routine histological evaluation is fairly adequate to assess differentiation, tumor proliferative activity is difficult to measure. Silver staining for nucleolar organizer regions (AgNORs) is reported to be helpful for assessing tumor proliferation. We investigated the AgNOR counts in 20 formalin fixed, paraffin embedded human prostate tissues in three microscopic fields of 330X, using an image analysis system. A total of 200-700 nuclei were evaluated on histologically controlled areas of nonneoplastic prostate tissue, prostatic intraepithelial neoplasia (PIN), and invasive carcinoma. The values were compared to flow cytometrically obtained synthesis phase fractions (SPF) and immunohistochemically semi-quantitated, proliferative cell nuclear antigen (PCNA) patterns. AgNOR counts were also compared to tumor stage and Gleason's score. The pattern of PCNA staining in formalin fixed specimens was widely variable, probably due to differences in preservation of antigen. The positive counts varied from 0 to 55%, with a mean value of 8.55 +/- 15.9. The SPF values ranged from 5 to 13% with a mean value of 8.50 +/- 2.37. Two of 20 tumors were aneuploid and 18 were of diploid range. The mean AgNOR values in nonneoplastic nuclei (1.836 +/- 0.299), PIN (3.129 +/- 0.295), and invasive tumor cell nuclei (4.737 +/- 0.369) were highly significant (P < 0.0001) when paired differences were compared. AgNOR counts correlated significantly with tumor Gleason's score (P < 0.0145). However, the correlation coefficient for SPF and AgNOR values was not significant (P > 0.24), possibly because of the small number of samples examined. The highest AgNOR counts were found in the two aneuploid tumors. We conclude that AgNOR count may be a potential indicator of cellular proliferation, and possibly a marker of tumor differentiation.

Aneuploidy↗
PubMed1993

Detection of human papillomavirus (HPV) DNA in human prostatic tissues by polymerase chain reaction (PCR).

Human papillomavirus (HPV) infections are strongly linked to the pathogenesis of uterine cervical neoplasms, and have been implicated in other cancers of the female genital tract. In contrast, the association of HPV with the cancers of the male urogenital tract is less evident, except in anal and penile cancers. However, recent studies reporting the prevalence of HPV infections in human prostate cancers (60-100% HPV 16 positive vs. no infection of HPV) have raised controversies regarding the prevalence of HPV in benign and neoplastic human prostate. We investigated the prevalence of HPV infections in prostatic intraepithelial neoplasia (PIN) and prostatic adenocarcinomas in 23 surgically resected prostates. Polymerase chain reaction (PCR) was used to amplify HPV 6b/11, 16, and 18 specific DNA sequences, using type specific HPV primers selected from the transforming gene E6-E7. The areas of PIN and cancer in 6 microns H&E stained tissue sections were identified, and respective areas of PIN and cancer were isolated from the adjacent serial sections and used for DNA amplification and HPV detection (Fig. 1). Our results demonstrated the presence of HPV 16 in three carcinomas (13%), using type specific primers in PCR amplified samples. We were not able to demonstrate the presence of other HPV types (HPV 6b/11 or HPV 18) in any of the samples using specific primers. Two of these prostates showed relatively strong positive signals by dot blot analysis, when hybridized with a 32P-labeled HPV 16 type specific oligonucleotide probe. One more sample showed weak positivity, when hybridized with a 32P-labeled HPV 16 type specific oligonucleotide probe. Subsequently, we have confirmed these results by Southern hybridization of the samples transferred to nylon membrane after agarose gel electrophoresis and detected by HPV 16 type specific oligonucleotide probe, using chemiluminescent assay. We, therefore, conclude that HPV infections of the prostate in general are not as common as has been previously claimed by other investigators.

Adenocarcinoma↗
PubMed1993

Concurrent abnormal expression of ERBB-2, EGFR, and p53 genes and clinical disease progression of breast carcinoma.

Metastatic phenotype in human solid tumors is believed to follow stochastic acquisition of structural genetic aberrations-so-called multistep tumor progression. We tested this hypothesis in breast carcinoma by immunostaining 89 stage-heterogeneous cases for the products of three genes (p53, ERBB-2, and EGFR) which are frequently altered in this tumor system. Variable relationships were observed between advanced disease stage and immunostaining for individual gene products (ERBB-2 - p = 0.05, EGFR - p = 0.02, p53 - p = 0.12, Chi Square test). Regional or distant metastases at presentation correlated with multiple oncogene/tumor suppressor gene expression abnormalities: node negative -59% none positive, 29% one positive, 12% two or more positive, vs. node positive -37% none positive, 23% one positive, 39% two or more positive (p = 0.01). Only 2/12 (17%) of tumors with distant metastases at presentation were negative for abnormal expression of any of these gene products, and 7/12 (58%) were positive for two or three. Among axillary node negative patients who developed recurrences, 67% exhibited staining for at least one gene product, compared to only 27% of those without recurrences (p = 0.02). All 5 cases with abnormal staining for each gene product had regional or distant metastases at presentation and recurred. In multivariate analysis, individual expression of p53 outweighed expression of ERBB-2 and EGFR in correlation with outcome. These data suggest clinical neoplastic progression of breast carcinomas correlates with cumulative genetic events detectable by protein expression. Short term recurrence, however, may correlate more closely with abnormal expression of p53 than with EGFR or ERBB-2.

Breast Neoplasms↗
PubMed1993

Immunohistologic analysis of invasive phenotype in breast carcinoma. A clinicopathologic study.

Acetone-fixed, cryostat sections of 81 snap-frozen invasive breast carcinomas were immunostained with monoclonal antibodies to Cathepsin D (CD), a protease believed to mediate extracellular matrix dissolution, and Type IV collagen, a constituent of basal lamina (BL). Most cases (48/81, 53%) exhibited focal, patchy BL distribution (1+) around tumor cell nests, although subsets with diffuse continuous (2+) peritumoral sheets (15/81, 19%) or near complete absence (0+, 23/81, 28%) were also observed. Elaboration of BL was correlated with favorable morphologic differentiation (0+ BL-57% poorly differentiated vs. 2+ BL-13% poorly differentiated, p = .01), absence of nodal or systemic metastases (0+ BL-78% metastatic vs. 2+ BL-40% metastatic, p = .02), and improved disease-free survival (0+ BL-63% recurred vs. 2+ BL-20% recurred, p = .05). In addition, neoplastic cells expressed CD more frequently in tumors which lacked detectable BL synthesis (0+ BL-91% CD+ vs. 2+ BL-57% CD+, p = .03). The observed relationships between morphologic growth pattern, BL synthesis and CD expression imply conventional grading in large parts reflects activity or extent of host tissue invasion by a given neoplasm. Widespread but heterogeneous distribution of BL in breast tumors also suggests partial equilibrium between neoplastic and host tissues in most cases.

Antibodies, Monoclonal↗
PubMed1993

Use of the polymerase chain reaction for the detection of alternatively spliced mRNAs of plasma membrane calcium pump.

Polymerase chain reaction [PCR, reverse transcriptase-PCR (RT-PCR)] has been used to amplify the mRNA subspecies of the plasma membrane calcium pump isoform 1 (PMCA1) in total RNA extracted from hamster tissues. Two primers were synthesized that encompass the site at which a 154-bp exon is included totally (PMCA1a), partially (PMCA1c and d), or completely excluded (PMCA1b) in the carboxy-terminal regulatory region. PCR amplification revealed two bands (PMCA1b and 1c) that are more abundant in various tissues, while Southern hybridization of the samples after PCR amplification has detected two additional mRNA variants corresponding to PMCA1a and 1d. The distribution of these mRNA variants are tissue specific and correlate well with the pump protein distribution patterns on immunoblot. Since these multiple bands on the immunoblot are not derived from proteolysis, it is suggested that they represent the PMCA1 isozymes encoded by these alternatively spliced mRNAs. To our knowledge, this is the first report to show all four alternatively spliced mRNAs that are simultaneously detected in one single RNA sample using PCR technique. Since these isozymes are different in their regulatory domain, their tissue-specific expression may be physiologically important.

Alternative Splicing↗
PubMed1993

Molecular cloning and sequencing of an intron of Her-2/neu (ERBB2) gene.

This report documents the cloning and sequencing of a previously unknown intron of the Her-2/neu gene and compares three different cloning strategies for efficient PCR cloning. Although successful results have previously been documented using blunt-end ligation strategies, the TA cloning system (Invitrogen, CA) offered the best result in our hands using a PCR-amplified DNA fragment of Her-2/neu (ERBB2) gene containing an unreported intron. The TA cloning system is easy to manipulate and the cloned DNA can be easily sequenced without further subcloning into the M13 vector. Additionally, this cloning strategy does not require (i) any prior selection of restriction sites during primer design, (ii) post PCR restriction digestion, and/or (iii) gel purification of PCR-amplified DNA. The newly identified and sequenced DNA of the Her-2/neu neu intron (GenBank Accession No. M95667) may help in designing primers for the analysis of the Her-2/neu gene in biological specimens. Therefore, we recommend the TA cloning system as the preferred choice for cloning any DNA fragments generated by PCR.

Base Sequence↗
PubMed1993

Quantitative analysis of Her-2/neu (ERBB2) gene expression using reverse transcriptase polymerase chain reaction.

Inappropriate expression of Her-2/neu (ERBB2) gene has been associated with impaired breast cancer prognosis, suggesting a functional role in tumor progression. Herein we describe a quantitative method for analysis of Her-2/neu gene messenger RNA (mRNA), which employs reverse transcriptase polymerase chain reaction (RT-PCR) on a 10-microns cryostat section. The technique combines modified RNA extraction with complementary DNA (cDNA) synthesis to achieve a high level of sensitivity. Utilizing this PCR-based gene expression assay, we were able to quantitate variable amounts of Her-2/neu mRNA in cell lines with established levels of gene expression and in clinical human breast cancer specimens. In clinical samples, mRNA levels correlated with intensity of immunoperoxidase staining for corresponding oncoprotein. We conclude that PCR-based mRNA quantitation can be applied to quantitative analysis of Her-2/neu gene expression, and potentially many other genes, in samples of limited size.

Base Sequence↗
PubMed1993

Clinicopathologic significance of p53 immunostaining in adenocarcinoma of the breast.

Methanol/acetone-fixed frozen sections of 87 breast carcinomas were studied with a panel of three anti-p53 monoclonal antibodies that had specificities for wild-type, mutant, or combined wild-type plus mutant epitopes by using the avidin-biotin method. Nuclear staining was present in 13 (15%) of 87 cases with the mutant-specific antibody. The combined-specificity antibody stained 28 (32%) of 87 cases, including all but one of the tumors that was positive with the mutant-specific antibody. None of the cases reacted with the wild-type-specific antibody. Immunostaining for mutant form p53 was strongly correlated with adverse clinicopathologic factors, including poor differentiation, absence of estrogen receptor protein, nodal metastases, and large tumor size. In groups that were stratified by axillary node status, disease-free survival (52-month mean follow-up) was worse among cases with positive staining for either antibody. This difference was statistically significant in node-positive patients with the combined-specificity antibody (disease free, 22% [p53+] vs recurred, 57% [p53+]). We concluded that (1) immunostaining for mutant forms of p53 characterizes a clinically aggressive subset of breast tumors and may have prognostic utility in some patient populations, and (2) antibody-dependent-staining patterns for p53 may reflect epitope specificities of various mutant forms.

Adenocarcinoma↗