Ki-67 Immunoreactivity Research Articles

Immunohistochemical expression of p53 and Ki67 in colorectal adenomas and prediction of malignancy and development of new polyps

The aim of this study was to investigate the immunohistochemical expression of p53 and Ki67 in colorectal adenomas in order to clarify their significance as indicators of malignancy and development of new polyps. Seventy-eight polyps were removed from 51 patients and examined. Twenty-nine patients (56.9%) had adenomas with low-grade atypia (13 of them developed new polyps at 3-year follow-up) and 22 (43.1%) had adenomas with high-grade atypia (6 of them developed new polyps at 3-year follow-up). We tested the association between p53 and Ki67 expression and various clinicopathological variables, and regression analysis was performed to identify the risk factors for malignancy and development of new adenomas. A significant correlation between the grade of atypia and p53 immunoreactivity was observed. Ki67 expression was not related to atypia and no correlation was found between p53 and Ki67 immunoreactivity. Regression analysis showed that size (p=0.0002) and p53 staining (p=0.0111) were the selected factors related to malignant transformation, whereas the number of synchronous primary polyps emerged as the only predictive factor of development of new adenomas, although without statistical significance. The expression of biological markers may be in future added to the currently examined features of polyps; however, further studies are needed to better define their predictive value.

Transient Impairment of Hippocampus-dependent Learning and Memory in Relatively Low-Dose of Acute Radiation Syndrome is Associated with Inhibition of Hippocampal Neurogenesis

Neurogenesis in the adult hippocampus, which occurs constitutively, is vulnerable to ionizing radiation. In the relatively low-dose exposure of acute radiation syndrome (ARS), the change in the adult hippocampal function is poorly understood. This study analyzed the changes in apoptotic cell death and neurogenesis in the DGs of hippocampi from adult ICR mice with single whole-body gamma-irradiation using the TUNEL method and immunohistochemical markers of neurogenesis, Ki-67 and doublecortin (DCX). In addition, the hippocampus-dependent learning and memory tasks after single whole-body gamma-irradiation were examined in order to evaluate the hippocampus-related behavioral dysfunction in the relatively low-dose exposure of ARS. The number of TUNEL-positive apoptotic nuclei in the dentate gyrus (DG) was increased 6-12 h after acute gamma-irradiation (a single dose of 0.5 to 4 Gy). In contrast, the number of Ki-67- and DCX-positive cells began to decrease significantly 6 h postirradiation, reaching its lowest level 24 h after irradiation. The level of Ki-67 and DCX immunoreactivity decreased in a dose-dependent manner within the range of irradiation applied (0-4 Gy). In passive avoidance and object recognition memory test, the mice trained 1 day after acute irradiation (2 Gy) showed significant memory deficits, compared with the sham controls. In conclusion, the pattern of the hippocampus-dependent memory dysfunction is consistent with the change in neurogenesis after acute irradiation. It is suggested that a relatively low dose of ARS in adult ICR mice is sufficiently detrimental to interrupt the functioning of the hippocampus, including learning and memory, possibly through the inhibition of neurogenesis.

Differentiated Intraepithelial Neoplasia of the Vulva

We present the clinical and pathological findings of 6 women with intraepithelial neoplasia of differentiated or simplex type (DVIN). The mean age was 68 years (range 55-82). One lesion was still in situ, whereas 5 were associated with squamous carcinoma, 4 of well-differentiated keratinizing type and 1 of poorly differentiated spindle-cell type. The invasive depth of the squamous carcinomas ranged from 0.6 to 8 mm and the surgical margins of all of the resection specimens were uninvolved by neoplastic cells. In contrast, DVIN involved the surgical margins in 5 specimens while the remaining specimen had normal surgical margins. In all 6 vulvar specimens, DVIN showed intense immunoreactivity for Ki-67 in the basal and parabasal cells while only 4 specimens showed reactivity for p53. In 5 surgical specimens with DVIN the number of CD1a cells was increased but little if any immunoreactivity could be found amongst the corresponding invasive neoplastic cells. Four squamous carcinomas also showed diffuse p53 reactivity. There was little difference in the pattern of Ki-67 expression between DVIN and squamous carcinoma. For a number of reasons, DVIN present diagnostic difficulty and considerable interobserver variation also exists. Our study suggests that Ki-67 and p16 are useful for distinguishing DVIN and classical VIN 3, whereas p53 and CD1a are useful for distinguishing DVIN and invasive squamous carcinoma. Furthermore, p53 appears to have higher specificity than sensitivity for distinguishing DVIN from normal squamous epithelium.

Diagnostic and prognostic significance of cyclin A expression in low-grade astrocytomas: comparison with astrogliosis and high-grade tumours

Aim:Definitive distinction between low-grade astrocytoma and astrogliosis is a long-standing difficulty due to their similar histopathological characteristics. To clarify differences in biological significance, this study focused on various components of...

Global gene expression profiling and histochemical analysis of the developing human fetal pancreas

An immunohistochemical and genomic analysis of human pancreatic development from 9-23 weeks of fetal age was undertaken to provide a comparative analysis of human and murine islet development. Human fetal pancreases obtained at gestational ages 9-23 weeks were processed in parallel for immunohistochemistry and gene expression profiling by Affymetrix microarrays. By 9-11 weeks, the pancreas was made up principally of mesenchymal tissue infiltrated by branched epithelial structures containing scattered hormone-negative neurogenin3-positive endocrine cells. Protoacinar structures emerged by 15-19 weeks, along with clusters of endocrine cells producing either glucagon or insulin. By 20-23 weeks, vascularised islet-like structures appeared. More than 70% of endocrine cells produced a single hormone at any age. Analysis of Ki67 immunoreactivity showed that the replicative rate of endocrine cells was low and suggested that the endocrine expansion was derived from hormone-negative precursors. Insulin, glucagon, somatostatin, ghrelin and pancreatic polypeptide transcripts were present at 9-10 weeks and increased progressively, commensurate with the expansion of endocrine cell volume. The human equivalent of a mouse endocrine secondary transition was not evident, neither in terms of morphology nor in dramatic changes in endocrine-specific transcriptional regulators. By contrast, exocrine genes showed a marked transition at around 11 weeks, associated with a greater than sixfold increase in exocrine gene transcripts. The observed extension of terminal differentiation of human endocrine tissue into late gestation is in contrast with findings in the mouse. It indicates that the human fetal pancreas could provide an abundant islet precursor cell population that could be expanded ex vivo for therapeutic transplantation.

Angiotensin II mimics the hypoxic effect on regulating trophoblast proliferation and differentiation in human placental explant cultures

Regulation of cytotrophoblast differentiation toward extravillous trophoblasts (EVTs) is critical for establishing successful pregnancy. Previous studies have focused primarily on the factors promoting the differentiation, while inhibitory regulators except hypoxia have been less documented. In this study, to test our hypothesis that angiotensin II (Ang II) would inhibit EVT differentiation, we investigated the effects of Ang II on trophoblast outgrowth and the expression of molecules associated with the proliferation and invasion of trophoblasts using human first trimester villous explant cultures. Ang II increased EVT outgrowth and the number of cells in cell columns. Moreover, Ang II-treated explants exhibited increased Ki67 and integrin α5 immunoreactivity in EVTs as well as matrix metalloproteinase-2 activity in the conditioned media, and decreased α1 integrin immunoreactivity, which are compatible with the features of the proliferative phenotype EVTs. These effects of Ang II were similar to those of hypoxia (3% O 2). Ang II stimulated the expression of hypoxia inducible factor-1α at both mRNA and protein levels, and also enhanced the expression of plasminogen activator inhibitor-1 (PAI-1). Data presented herein suggest a possible role for Ang II in impairing trophoblast differentiation toward an invasive phenotype, which might be associated with shallow invasion in preeclamptic placentas.

Morule-like features and tumor-associated lymphoid proliferation in gallbladder carcinoma

A unique case of gallbladder carcinoma with morule-like features and tumor-associated lymphoid proliferation in a 53-year-old man is presented. The surgically resected gallbladder demonstrated a polypoid tumor with a thin stalk, measuring 1.3 x 0.5 cm. Histologically, a well-differentiated tubular adenocarcinoma was accompanied by multiple spindle cell nodules. The stroma of the tumor showed dense lymphocytic infiltrate. Immunohistochemically, the spindled cell nodules were diffusely positive for cytokeratin AE1/AE3 but negative for S-100, NSE, and chromogranin A. The immunohistochemical results considered to be spindle cell nodules were morule-like features. Intranuclear expression of beta-catenin was observed in morule-like features and carcinoma cells. Ki-67 labeling index was 16.7% of carcinoma cells, but Ki-67 immunoreactivity was negative in spindle cell nodules; therefore, morule-like features were considered to represent metaplastic foci of carcinoma cells and not nodular growth of carcinoma cells. Although the exact pathogenesis of marked lymphoid proliferation in the stroma remained unknown, tumor-produced substances may derive from lymphoid proliferation.

Prognostic Implications of Numb Immunoreactivity in Salivary Gland Carcinomas

The gene numb encodes for a protein (Numb) involved in cell fate decisions in Drosophila, with proposed endocytic and developmental functions in mammalians. The distribution pattern of Numb in human tissues however, has not been fully characterized. We set out to explore the immunohistochemical expression of Numb in normal and neoplastic (28 adenoid cystic and 34 mucoepidermoid carcinomas) salivary glands, and correlated the results with the clinico-pathologic features of the neoplasms. Intense Numb immunoreactivity was detected in normal ductal cells and in a subset of acinar cells. In salivary carcinomas, we detected diffuse and intense Numb immunostaining in 5 adenoid cystic and 8 mucoepidermoid carcinomas. By contrast, the majority of adenoid cystic and mucoepidermoid cancers showed only moderate (14 and 5 cases) or focal staining (9 and 21 cases), respectively. The corresponding expression of Numb mRNA was documented in normal parotid gland and adenoid cystic carcinoma. Numb immunoreactivity was inversely correlated with the histological grade and Ki-67 immunoreactivity of both adenoid cystic and mucoepidermoid carcinomas. In addition, while tumor grade, stage, Ki-67 and Numb immunoreactivity were associated with disease-free survival in univariate analysis, only Numb and Ki-67 immunoreactivities retained independent prognostic significance in multivariate analysis. These data suggest that loss of Numb is implicated in aberrant differentiation programs of salivary gland carcinomas and may serve as a prognostic indicator in patients treated for these neoplasms.

Deviated Mechanism of Wound Healing in Diabetic Corneas

We examined phenotypic changes during the wound healing process in the corneal epithelium of Goto-Kakizaki (GK) rats, a spontaneous model of type 2 diabetes mellitus. In this article, we provide an overview of our and other groups' research and describe the clinical features of diabetic keratopathy. We observed that the rate of corneal epithelial wound closure was decreased in GK rats compared with Wistar rats. Immunoreactivity for Cx43, K14, and Ki-67 was detected in the 2 layers of cells adjacent to the basement membrane in the corneal epithelium of GK rats, whereas only the single basal layer of cells was positive for these proteins in the corneal epithelium of Wistar rats. The frequency of Ki-67-positive cells was greater in GK rats than in Wistar rats in the intact corneal epithelium and during wound healing. The GK rat represents delayed corneal epithelial wound closure as well as that which is observed in human diabetic keratopathy. Furthermore, these results indicate a possibility of functional deviation in corneal epithelial cells with diabetes mellitus.

Do Proliferating Cell Nuclear Antigen and MIB-1/Ki-67 Have Prognostic Value in Penile Squamous Cell Carcinoma?

To evaluate the role of proliferating cell nuclear antigen (PCNA) and MIB-1/Ki-67 immunohistochemical expression in predicting lymph node metastasis and survival in primary penile squamous cell carcinoma. We conducted a retrospective evaluation of 125 patients with penile squamous cell carcinoma submitted to primary tumor treatment, with information on lymph node status. Clinical and pathologic data for PCNA and MIB-1/Ki-67 expression in the primary tumor were analyzed. Correlations between these data and lymph node metastasis risk and survival were calculated. In univariate analysis, low MIB-1/Ki-67 expression, the presence of lymphovascular permeation, clinically positive lymph nodes, tumor thickness greater than 5 mm, and infiltration of cavernous bodies were correlated with lymph node metastasis. However, the independent factors for lymph node metastasis risk were PCNA and MIB-1/Ki-67 immunoreactivity, lymphovascular permeation, and N clinical stage. Independent variables for disease-free survival were urethra infiltration and the presence of lymph node metastasis. For death risk evaluation the independent variables were age, lymph node metastasis, and clinical stage. There was a correlation between PCNA and MIB1/Ki-67 immunohistochemical expression and the presence of lymph node metastasis. However, PCNA and MIB1/Ki-67 immunohistochemical expression did not have a relationship with survival and death risk.

Hemangiomas and Angiosarcomas of the Breast: Diagnostic Utility of Cell Cycle Markers With Emphasis on Ki-67

Vascular tumors comprise a minor subgroup of tumors arising in the breast and represent variants of hemangiomas and angiosarcomas. Diagnostic challenges may arise when differentiating hemangiomas from types I and II angiosarcomas. Ki-67 expression has been used as an adjunct to distinguish between benign and malignant lesions exhibiting histologic overlap at various anatomic sites. To investigate the utility of Ki-67 and other cell cycle regulatory proteins (S-phase kinase-associated protein 2 [Skp2], p27, and cyclin D1) in the differential diagnosis of mammary vascular lesions. Thirty-four vascular tumors (21 hemangiomas and 13 angiosarcomas) of the breast were studied. The Ki-67 index and immunoreactivity for Skp2, p27, and cyclin D1 were determined in each case. Appropriate statistical methods were used. The mean value of Ki-67 index was statistically different when comparing hemangiomas and angiosarcomas (P < .001). Angiosarcomas were typically positive for Skp2, whereas hemangiomas were negative (P < .001). Sensitivity and specificity cutoffs for Ki-67 index to distinguish hemangiomas from angiosarcomas showed a candidate cutoff point of 175. The mean values of Ki-67 of low-grade angiosarcomas were significantly different from all hemangiomas (P < .001) and also different from the subset of atypical hemangiomas (P = .02). Sensitivity and specificity cutoffs for Ki-67 index to distinguish all hemangiomas from low-grade angiosarcomas showed a candidate cutoff point between 150 and 175. Among angiosarcomas, positivity for Ki-67 was inversely related to that of p27 but not to Skp2 or cyclin D1. This was also true among hemangiomas. Ki-67 index can be used as a diagnostic tool to distinguish between benign and malignant vascular lesions of the breast. This can be particularly helpful in cases of histologic overlap such as low-grade angiosarcoma and hemangioma.

Immunohistochemical Assessment of Ki-67 Expression in Adenoid Cystic Carcinoma of the Salivary Glands

Objective Adenoid cystic carcinoma (ACC) is a rare malignant tumor originating from the salivary glands. It’s rather bland histological appearance that masks its ultimate biological aggressiveness. Evaluation of cell cycle and mitoses have been useful in predicting malignancy in many tumors. Ki-67 antigen is a human nuclear antigen that presents during all active phases of cell cycle. The aim of this study was to estimate whether the Ki-67 expression ratio in ACC correlated with the morphological growth pattern and tumor histological grade. Material and Methods Tissue samples of 19 ACC, collected from the files in archive of Department of oral pathology, Mashhad Dentistry Faculty. All Samples originated from minor salivary gland including 11 men and 8 women with an avarage age of 46. One section have been stained with H&E to confirm the diagnosis and the other with Ki - 67 monoclonal antibody. All samples graded and scored for Ki-67 immunoreactivity, then the ratio of Ki-67 positive cells was calculated. Results The most incidence of tumor was in 4 and 5 decades and in women. The most common site of tumors was palate. Ki-67 expressed in 68% of all samples. The Ki-67 immunoreativity ranges from 15% to 85%. Although the avarage percentage of Ki-67 expression seems to increase with histological grade, but the difference between grade III and grade I, and between grade III and mixed I / II was not statistically significant (P value = 0.3). Conclusion For ACC, Ki-67 immunostaining regarding to histological grading is not a reliable tool in predicting the intensity of tumor aggressiveness and seems to have less value. Further studies with greater series of samples are needed to confirm this issue.

Immunohistochemical Analysis of PCNA, Ki67 and p53 in Nasal Polyposis and Sinonasal Inverted Papillomas

Immunoreactivity of proliferating cell nuclear antigen (PCNA), Ki67 and p53 in inflammatory nasal polyp and inverted papilloma tissues was investigated. Immunohistochemistry was performed using a standard avidin-biotin-peroxidase method, and the immunoreactivity of PCNA, Ki67 and p53 was quantified by counting immunostained nuclei in at least 1000 epithelial cells. The mean labelling index (percentage of immunostained cells) for PCNA was 40.68 in the inverted papilloma group and 14.73 in the nasal polyp group, and for Ki67 was 15.43 in the inverted papilloma group and 2.64 in the nasal polyp group. Both of these differences between the inverted papilloma and nasal polyp groups were significant. Immunoreactivity for p53 was detected in five (35.7%) inverted papilloma patients and two (9.5%) nasal polyp patients. The increase in epithelial cell proliferation seemed to be greater in inverted papillomas than in inflammatory nasal polyps. Increased epithelial cell proliferation may be involved in the development of inverted papillomas.

The Influence of Fluticasone Inhalation on Markers of Carcinogenesis in Bronchial Epithelium

Bronchial epithelium exposed to cigarette smoke undergoes a series of histologic changes that may ultimately lead to invasive cancer. Inhaled corticosteroids reduce the number of lung tumors developing in rats exposed to cigarette smoke. We studied the effect of inhaled fluticasone on premalignant lesions in smokers and patients curatively treated for head and neck cancer or lung cancer. Participants were screened for premalignant lesions by bronchoscopy. Biopsies were taken from three to five locations and classified using WHO criteria. In case of a metaplasia index of > 15%, participants were randomized to receive a powder inhalation device containing either fluticasone 500 microg or a placebo, to be used twice a day. After 6 months, biopsies were obtained from the same locations as previously sampled. Efficacy of treatment was assessed by reversal of metaplasia/dysplasia; secondary endpoints were reversal of increased p53 and KI-67 immunoreactivity and expression of human telomerase reverse transcriptase. Of the 201 subjects that were screened, 108 were included. Mean age was 53 yr (35-71), mean number of pack-years 48 (18-99), mean metaplasia index 48%, and 32% had some degree of dysplasia at baseline. The two treatment arms did not differ with respect to response or change in either metaplasia index or the expression of the markers p53, KI-67, or human telomerase reverse transcriptase. Inhaled fluticasone in a dose of 500 mug twice a day does not affect the natural course of premalignant lesions in the central airways.

Investigation of Proliferative Activity in the Developing Human Tooth Using Ki-67 Immunostaining

Objective: The aim of this study was to investigate the proliferation of the developing human tooth germ and its surrounding tissues using Ki-67 immunostaining. Materials and Methods: Sections of mandibular dental arch tissues collected from 4 cadaveric human fetuses of 13, 16, 21 and 30 weeks of gestation were used. The immunoreactivity of Ki-67 in the tissue sections was assessed visually under a light microscope. Immunohistochemical controls were performed by replacing the primary antibody with phosphate-buffered saline or normal rabbit lgG. Results: The control sections did not display Ki-67 immunoactivity. Specimens of 13 weeks of gestation revealed intense Ki-67 immunostaining throughout the entire developing mandibular primary molars. At 16 weeks of gestation, immunostaining was observed in the inner enamel epithelium and dental papilla, in conjunction with the dental lamina showing decreased immunostaining. At 21 weeks, Ki-67 immunostaining was observed only in the inner enamel epithelium and dental papilla. The immunoreactivity of active ameloblasts and odontoblasts decreased, along with the proliferation capacity of the dental lamina. At 30 weeks, both enamel and dentin formation was observed along the cusped aspect of the tooth germ. Ameloblasts and odontoblasts were no longer immunoreactive in this region, while both types of cells were immunoreactive at the cervical regions of the crown. Dental lamina cells showed disintegration and were totally Ki-67-negative at 30 weeks of gestation. Conclusion: The Ki-67 immunoreactivity of the dental lamina decreased during intrauterine tooth development. Positive immunostaining was observed at specific sites in the enamel organ and dental papilla during the cap and bell stages.

Endocrine tumors of the gastrointestinal tract and pancreas:grading, tumor size and proliferation index do not predict malignant behavior

ContextGastrointestinal and pancreatic (GIP) endocrine tumors (ETs) have been regarded as slow growing neoplasms with distinct morphologic characteristics that behave less aggressively than carcinomas. The malignant potential of these tumors is difficult to predict.ObjectiveTo evaluate prognostic parameters, namely tumor size, tumor grade, and Ki-67 index in relationship to metastatic behavior of GIP ETs.DesignBiopsies and surgical specimens from 38 patients with GIP ETs were selected. The study group comprised 16 males and 22 females (mean age 62.6 years; range 24–91). Formalin-fixed, paraffin-embedded tissue sections were stained with H&E, synaptophysin, chromogranin A, and Ki-67. Ki-67 index was evaluated using ChromaVision Automated Assisted Image Analysis software. Proliferative index was compared to tumor grade, and the degree of associations between tumor size, tumor grade, Ki-67 index and metastatic behavior of GIP ETs were evaluated.ResultsFifteen of the twenty-two (68.18%) surgically staged neoplasms presented with peritoneal dissemination, lymphogeneous, and/or hematogeneous metastases. Nine of the metastatic tumors were G1 (9/13, or 69.23%), 5 were G2 (5/7, or 71.42%), and 1 – G3 (1/2, or 50%). Overall, 10/15 (66.66%) metastatic tumors showed < 2% Ki-67 immunoreactivity. Four ileal ETs had a synchronous malignancy. No significant correlation was found to exist between tumor grade and Ki-67 index as well as between tumor size, tumor grade, Ki-67 index and metastatic behavior.ConclusionThe findings suggest that tumor size, tumor grade and Ki-67 index do not accurately predict malignant behavior of GIP ETs.

Ki-67 Immunoreactivity in the Differential Diagnosis of Pulmonary Neuroendocrine Neoplasms in Specimens With Extensive Crush Artifact

Ki-67 Immunoreactivity in the Differential Diagnosis of Pulmonary Neuroendocrine Neoplasms in Specimens With Extensive Crush Artifact

Long-term follow-up of conservatively managed incidental carcinoma of the prostate A multivariate analysis of prognostic factors

To evaluate the disease-specific mortality of conservatively managed incidental carcinoma of the prostate (T1a and T1b) in relation to prognostic factors. Since 1987 all patients with prostate cancer have been recorded and followed in the population-based Prostate Cancer Register of the South-East Healthcare Region in Sweden, which is covered by four departments of pathology. At two of these departments, tissue was obtained from 197 consecutive, previously untreated patients (aged <80 years) with incidental carcinoma who underwent transurethral resection of the prostate between 1987 and 1991. The amount of tumour, Gleason score and levels of Ki-67, p53, chromogranin A and serotonin were determined. Univariate analysis and multiple Cox regression hazard analysis were used for analysis. During follow-up (mean 7.8 years; maximum 17.5 years), 158 patients (80%) had died, 33 of them of prostate cancer, corresponding to 17% of the entire cohort. Of 86 patients with Gleason score < or =5, three died of prostate cancer. Independent predictors of disease-specific mortality in multivariate analysis were category T1b prostate cancer, Gleason score >5 and high immunoreactivity of Ki-67. Elderly men with category T1a and/or Gleason score 4-5 prostate cancer have a favourable prognosis with conservative management. Immunohistochemical staining with Ki-67 may be of help in situations where further prognostic information is required.

Phosphorylated Histone H3, Ki-67, p21, Fatty Acid Synthase, and Cleaved Caspase-3 Expression in Benign and Atypical Granular Cell Tumors

Granular cell tumors (GCTs) are classified as benign when none of the following features is present: spindling of the tumor cells, necrosis, diffuse pleomorphism, prominent nucleoli, high nuclear-cytoplasmic ratio, and mitotic rate >2 per 10 high-power fields. It has been suggested that a GCT be classified as atypical when 1 or 2 of these features are seen and as malignant when 3 or more of these are present. In our practice, we do not classify GCTs as malignant in the absence of metastasis. To compare immunohistochemical staining for phosphorylated histone H3 (PHH3), Ki-67 (MIB-1), p21, fatty acid synthase, and cleaved caspase-3 in histologically classified benign and atypical GCTs. We reviewed 25 cases of GCT from our archives and classified 14 as atypical based on histologic features. Immunohistochemical staining for PHH3, Ki-67, p21, fatty acid synthase, and cleaved caspase-3 was performed using standard methods. The number of positive cells for Ki-67, p21, and PHH3 was calculated in 10 consecutive high-power fields in a hot spot. Fatty acid synthase and cleaved caspase-3 cytoplasmic expression was graded from 1 to 3. Ki-67 and PHH3 scores were significantly higher in atypical GCTs. The expression of p21, fatty acid synthase, and cleaved caspase-3 was not significantly different between atypical and benign GCTs. This study shows that histologic features are reliable in identifying GCTs that have a higher proliferative potential as shown by higher immunoreactivity for Ki-67 and PHH3. These immunostains may help in classifying GCTs in cases where a thorough histologic evaluation is precluded by the small size of a biopsy specimen.

Differential expression of human telomerase catalytic subunit mRNA by In situ hybridization in pheochromocytomas

In pheochromocytomas, it is very difficult to predict malignant potential by conventional histology or immunohistochemical and molecular markers. We investigated the expression of human telomerase catalytic component (hTERT) mRNA, hTERT protein, Ki-67 antigen, and p27kip1 in pheochromocytomas (27 benign, 7 suspected malignant, and 7 malignant), and evaluated the possibility of expressions of these proteins, and hTERT mRNA serve as diagnostic markers for predicting the biological behavior of these tumors. All tumors showed the classical histology and typical immunohistochemical pattern. By in situ hybridization, hTERT mRNA was expressed in 5/7 malignant tumors (defined as the presence of metastasis and/or extensive local invasion) as compared with 3/27 benign tumors. We examined the hTERT by immunohistochemistry to confirm the mRNA. hTERT mRNA expression was correlated with hTERT protein expression. All benign tumors exhibited no immunopositivity or <1% of cells stained for Ki-67 antigen. Six out of seven malignant tumors have shown either hTERT mRNA expression or Ki-67 immunoreactivity. While no statistical difference in p27kip1 expressions was observed among benign, malignant, and suspected malignant tumors, there was a statistical difference between the normal adrenal medulla samples and tumors (p < 0.001). Thus, hTERT mRNA detection by in situ hybridization, hTERT expression, and Ki-67 antigen expression are all useful tools for differentiating malignant from benign pheochromocytomas.