Predictive value of topoisomerase II alpha immunostaining in urothelial bladder carcinoma

AIMS: The nuclear enzyme DNA topoisomerase II has been shown to be required for chromatin condensation and chromosomal segregation during mitosis; its isoform topo II alpha is linked with active cell proliferation in mammalian cells. The aim of this study was to examine the relation of the expression of topo II alpha to the biological behaviour of conventional urinary bladder cancer. METHODS: Formalin fixed, paraffin wax embedded tissue from 94 specimens of bladder urothelial cancer were immuno-histochemically stained for topo II alpha. For each case, a topo II alpha index was determined. A similar index had been determined for Ki-67, a known cell proliferation marker. Each case had also been graded, staged, and evaluated for DNA ploidy as well as for p53 and bcl-2 immunoreactivity. RESULTS: Raised topo II alpha expression (in > or = 10% of malignant nuclei) correlated with two adverse prognosticators--high grade (p = 0.027) and invasion of the muscularis propria (p = 0.013), but with no other evaluated parameter. By multivariate survival analysis using Cox's proportional hazard model, high expression of topo II alpha was found to be predictive for worse survival (p = 0.0047). Patients' age, tumour stage, and grade were also retained as independent prognostic factors (p = 0.0349, p = 0.00005, and p = 0.0130, respectively). The negative influence of increased topo II alpha immunopositivity on patients' survival was also seen in the subgroup of patients with non-muscle invasive carcinomas (p = 0.0004), in patients with a bcl-2 negative phenotype (p = 0.0330), and in those with low Ki-67 indices (p = 0.0341). CONCLUSIONS: Because topo II alpha and Ki-67 failed to demonstrate a significant interrelation, they appear to be different molecules that both function at separate phases in the complex process of cellular proliferation. The assessment of increased topo II alpha immunoreactivity in specimens from urothelial carcinomas might help to select patients (particularly among those with superficial tumours) in the worse prognostic categories for new therapeutic strategies.     

p27kip1 expression distinguishes papillary hyperplasia in Graves' disease from papillary thyroid carcinoma.

In most cases, the histopathologic and cytologic distinction between Graves' disease and papillary thyroid carcinoma is relatively easy, but on occasion Graves' disease may simulate a thyroid papillary carcinoma. For example, papillary fronds with fibrovascular cores may be present in both Graves' disease and papillary carcinoma. p27kip1 (p27) is a cyclin-dependent kinase inhibitory protein that has been shown to be an independent prognostic factor in a variety of human tumors. Our previous studies of p27 expression in hyperplastic and neoplastic endocrine lesions showed that the level of p27 was quite different in these two conditions. To determine if this distinction could also be made between Graves' disease and papillary carcinoma, we analyzed expression of p27 and other cell cycle proteins in a series of cases of Graves' disease with papillary hyperplasia and a series of papillary thyroid carcinomas. Formalin-fixed paraffin-embedded tissues from 61 randomly selected patients with thyroid disease, including 29 cases of Graves' disease with papillary architectural features and 32 cases of papillary carcinoma, were analyzed for expression of p27, Ki-67, and DNA topoisomerase II alpha (topo II alpha) by immunostaining. The distribution of immunoreactivity was analyzed by quantifying the percentage of positive nuclei that was expressed as the labeling index (LI) plus or minus the standard error of the mean. The papillary hyperplasia of Graves' disease had a p27 LI of 68.2 +/- 3.1 (range, 24 to 88), whereas papillary carcinomas had a LI of 25.6 +/- 2.5 (range, 12 to 70) (P < .0001). No significant differences in Ki-67 or topo II alpha expression were identified between papillary hyperplasia in Graves' disease and papillary carcinoma. These results indicate that p27 protein expression is significantly higher in papillary hyperplasia of Graves' disease compared to papillary carcinoma, which may be diagnostically useful in difficult cases.     

Prognostic significance of p27Kip1, p45Skp2 and Ki67 expression profiles in Merkel cell carcinoma, extracutaneous small cell carcinoma, and cutaneous squamous cell carcinoma

AIMS: To compare the immunohistochemical expression of prognostic markers p27(Kip1), p45(Skp2) and Ki67 in Merkel cell carcinoma (primary neuroendocrine carcinoma of the skin, MCC), small cell neuroendocrine carcinoma of lung and urinary bladder (SNC), and cutaneous squamous cell carcinoma (SCC). METHODS AND RESULTS: Immunohistochemistry was performed using antibodies directed against p27(Kip1), p45(Skp2) and Ki67 on 72 tumour cases: 24 MCC, 25 SCC, and 23 SNC (15 from the lung and eight from the urinary bladder). Percentages of positive cells were determined for each marker and statistically analysed. Expression profiles on MCC and SCC were significantly different for all three markers. MCC and SNC exhibited significant similarities in their p27(Kip1) and p45(Skp2) expression profiles. In contrast, MCC and SNC differed significantly in their Ki67 proliferation indices, which were much higher in SNC. Additionally, MCC cases showed an association between increased proliferation indices and the appearance of local recurrence(s) and/or metastases. CONCLUSION: The immunohistochemical profile of MCC differs from that of SCC, in spite of their common oncogenesis and the supposed metaplastic origin of MCC, and resembles that of SNC, except for Ki67 levels, which were higher in the latter (characterized by greater biological aggressiveness). High levels of Ki67 also appear to be a prognostic factor in MCC.     

DNA topoisomerase II-alpha immunoreactivity as a marker of tumor aggressiveness in invasive breast cancer.

OBJECTIVE: The nuclear enzyme DNA topoisomerase (topo) II breaks and rejoins DNA strands; its isoform topo IIalpha is associated with active cell proliferation of mammalian cells. The aim of this study was to examine the relationship between the expression of topo IIalpha and biological behavior markers in breast cancer. METHODS: Formalin-fixed, paraffin-embedded tissue from 88 samples of infiltrating breast cancer was immunohistochemically stained for topo IIalpha. For each case, a topo IIalpha index was determined by image analysis. Similar indexes were available for Ki-67 protein, a known cell proliferation marker, and p53, bcl-2 and c-erbB-2 oncoproteins. Each case had been staged and graded and the patients had been followed up for a mean period of 61.62 months. RESULTS: Elevated topo IIalpha immunopositivity (in >10% of malignant nuclei) was detected in 22 tumors, and this immunostatus was statistically associated with poor nuclear differentiation, absence of steroid hormone receptors, high Ki-67 immunoexpression, p53 protein accumulation and c-erbB-2 protein overexpression. Topo IIalpha expression was not linked with disease extent (stage or lymph node status). Neither proliferation marker (topo IIalpha or Ki-67) had any significant influence on the patients' recurrence-free survival. CONCLUSION: From the above results, we conclude that topo IIalpha overexpression appears to be linked with cellular dedifferentiation and potentially aggressive tumor phenotype in invasive breast cancer.     

p27 Kip1 protein expression in Hashimoto's thyroiditis

AIMS: Hashimoto's thyroiditis (HT) is an autoimmune disease in which both proliferation and apoptosis are enhanced. p27(Kip1) protein protects tissues from disease mechanisms that involve excessive cell proliferation and apoptosis. This study investigated whether there is loss of p27(Kip1) expression in HT and whether p27(Kip1) immunoreactivity has any relation to the proliferative indicator Ki-67. Because p27(Kip1) is regulated through either degradation, mediated by the S phase kinase associated protein 2 (Skp2), or sequestration, via D3 cyclin, the expression of these proteins was also investigated. METHODS: Immunohistochemistry was used to assess p27(Kip1), Ki-67, Skp2, and cyclin D3 expression in 19 cases of HT and in 10 normal thyroids. The results were evaluated by image analysis and reported as labelling indices (LIs) in both groups. RESULTS: The p27(Kip1) LI was lower in HT than in normal thyroid (28% v 75%; p < 0.001), whereas Ki-67 (1.13% v 0.13%), Skp2 (0.74% v 0.15%), and cyclin D3 (1.56% v 0.00%) LIs were higher in HT than in normal thyroids (p < 0.001). There was no correlation between p27(Kip1) and the expression of Ki-67, Skp2, and cyclin D3. CONCLUSIONS: p27(Kip1) downregulation is not exclusive to tumours but occurs also in HT, independently of the proliferative status and of changes in Skp2 and cyclin D3 expression. Further investigation is required to understand the mechanisms leading to p27 deregulation because these observations suggest that the regulation of p27(Kip1) expression in epithelial thyroid cells may play a role in HT pathogenesis.     

Expression of cyclooxygenase-2, p53 and Ki-67 in gastric cancer

It has been reported that p53 mutation may contribute to upregulate cyclooxygenase (COX)-2 expression that is observed in malignant tissues. These molecules are involved in carcinogenesis by affecting tumor cell proliferation. The aim of this study was to examine the relationship between COX-2 or p53 expression and clinico-pathological characteristics including tumor cell proliferation in gastric cancer. COX-2 and p53 expressions were investigated with immunostaining, in tissue specimens obtained from 119 patients who underwent surgery for gastric cancer. The Ki-67 labeling index (LI) was counted by Ki-67 immunostaining. COX-2 and p53 expressions correlated significantly with depth of tumor invasion. However, there was no association between COX-2 or p53 expression and survival. p53 expression did not correlate with COX-2 expression. There was no significant difference in various clinicopathological variables between Ki-67 LI subgroups. The mean Ki-67 LI value of COX-2 positive tumors was significantly higher than that of negative tumors. The mean Ki-67 LI value of p53 positive tumors was not significantly higher than that of negative tumors. The mean Ki-67 LI value of both COX-2 and p53 positive tumors was significantly higher than that of both negative tumors. These results imply that COX-2 expression is associated with tumor cell proliferation of gastric cancer.     

Altered expression of p27Kip1‐interacting cell‐cycle regulators in the adult testicular germ cell tumors: potential role in tumor development and histological progression

We examined the potential role of cell‐cycle dysregulation in the development and histological progression of adult testicular germ cell tumors (TGCTs). Expressions of p27^Kip1‐interacting cell‐cycle regulators (down‐regulation of p27^Kip1 and overexpression of Skp2, Cks1, cyclin A, and cyclin E) and Ki‐67 labeling index (LI) were immunohistochemically examined in histological components of 50 intratubular germ cell neoplasms, unclassified (IGCNUs); 74 seminomas; and 25 embryonal carcinomas, identified from 88 patients. Altered expression of p27^Kip1, Skp2, Cks1, cyclin A, and cyclin E was observed in 20%, 12%, 16%, 10%, and 24% of IGCNUs; 26%, 36%, 27%, 89%, and 23% of seminomas; and 48%, 68%, 56%, 100%, and 60% of embryonal carcinomas, respectively. A significant difference in the frequency of Skp2 and cyclin A overexpression was observed between IGCNUs and seminomas. Significantly more frequent alterations of Skp2, Cks1, and cyclin E and p27^Kip1 were detected in embryonal carcinomas than in seminomas. Alterations of all cell‐cycle regulators were significantly more frequent in embryonal carcinomas than in IGCNUs. The mean Ki‐67 LI significantly increased from IGCNU (21.2%) through seminoma (34.7%) to embryonal carcinoma (54.2%). These results suggest that alterations of the p27^Kip1‐interacting cell‐cycle regulators are common in TGCTs and may be involved in their histological progression.     

S-phase kinase-associated protein 2 expression in non-Hodgkin's lymphoma inversely correlates with p27 expression and defines cells in S phase

The protein expression of the cyclin-dependent kinase inhibitor p27 is often deregulated in human tumors. In lymphomas the inactivation of p27 is achieved through either increased degradation(1) or sequestration via D cyclins,(2) and p27 protein levels have been shown to have a prognostic significance.(1,3) Recently, S-phase kinase-associated protein 2 (Skp2) has been proved to mediate p27 degradation in normal cells(4-7) and to have oncogenetic properties.(8,9) In this study, B-, T-, and myeloid hematopoietic cell lines and a well-characterized panel of human lymphomas (n = 244) were studied for the expression of Skp2. In human lymphomas, the expression of Skp2 strongly related to the grade of malignancy, being low in indolent tumors and very high in aggressive lymphomas. Moreover, the percentages of Skp2- and S-phase-positive cells, as measured by DNA content or BrdU labeling, strictly matched and closely parallel that of Ki-67 and cyclin A. An inverse correlation between Skp2 and p27 was found in the majority of lymphoma subtypes. Nonetheless, most mantle cell lymphomas and a subset of diffuse large cell lymphomas failed to show this correlation, suggesting that alternative pathway(s) for the regulation of p27 might exist. The detection of Skp2 protein either by flow cytometry or by immunohistochemistry represents a simple method to precisely assess the S phase of lymphomas. The potential diagnostic and prognostic value of Skp2 is discussed.     

Immunohistochemical analysis of bcl-2 and p53 expression in breast carcinomas: their correlation with Ki-67 growth fraction

We examined 59 breast cancers for p53 and bcl-2 protein expression by immunohistochemistry. The results were correlated with Ki-67 immunostaining. p53-negativity was noted in 40 cases and the remaining 19 tumours were p53-positive. Thirty-six tumours showed strong expression of bcl-2 and in 23 no staining for this protein was observed. We found statistically significant reverse correlation between expression of p53 and bcl-2 in majority of carcinomas: 31 cases were bcl-2 positive and p53-negative, and 14 tumours were bcl-2-negative and p53-positive. Six carcinomas showed no nuclear staining for Ki-67 and in the remaining 53 the percent of cancer cells positive for Ki-67 ranged from 1 to 60 (mean: 14.6). In these 53 cases we found that bcl-2-positive tumours were characterized by lower proliferation than bcl-2-negative tumours, the mean value of Ki-67 immunostaining being 10.7% and 23.0%, respectively. p53-negative tumours showed lower proliferation than p53-positive tumours: mean Ki-67 index was 10.2% and 23.9%, respectively.We conclude that immunohistochemically detected p53 and bcl-2 proteins show a significant inverse relationship in majority of breast carcinomas and their expression correlates with tumour proliferation (Ki-67 immunostaining).     

TGFB,TGFB Receptors,Ki-67, and p27(Kip)l Expression in Papillary Thyroid Carcinomas

Although most papillary thyroid carcinomas behave as low-grade neoplasms and are generally associated with a good prognosis, some subgroups of these neoplasms represent more aggressive variants. In order to determine if differences in the behavior of these papillary carcinomas were related to expression of growth factors or cell-cycle proteins, we analyzed a series of papillary carcinomas including the conventional or usual type (n=27), tall cell (n=27), diffuse sclerosing (n=5), and columnar cell (n=2) variants for expression of transforming growth factor beta (TGFβ), TGFβ receptors (TGFβ-RI and II, the proliferation marker Ki-67, and for the cell-cycle inhibitory protein p27^Kip1 (p27). All groups of thyroid tumors expressed TGFβ and TGFβ-RI and RII by immunohistochemical staining. These was a marked increase in the Ki-67 labeling index after staining with antibody MIB-1 in the columnar cell tumors compared to the other groups, but this difference was not significant because of the small number of tumors in this group. The cell-cycle inhibitory protein p27 was expressed in all groups and was not significantly different between groups. Normal thyroid cells had a higher labeling index for p27 compared to papillary carcinomas. These results indicate that TGFβ and TGFβ receptors I and II are commonly expressed in the usual and in variant forms of papillary thyroid carcinomas, and that there is decreased expression of p27 protein in all of these neoplasms compared to normal thyroid. The biological basis for the more aggressive behavior of these variants of papillary thyroid carcinoma remains uncertain.     

The spectrum of Merkel cell polyomavirus expression in Merkel cell carcinoma, in a variety of cutaneous neoplasms, and in neuroendocrine carcinomas from different anatomical sites

Most Merkel cell carcinomas display pure neuroendocrine differentiation (pure Merkel cell carcinoma), whereas a minority show combined neuroendocrine and nonneuroendocrine elements (combined Merkel cell carcinoma). Recent identification of Merkel cell polyomavirus DNA and Merkel cell polyomavirus large T antigen expression in a proportion of Merkel cell carcinomas has suggested viral-induced oncogenesis. To date, Merkel cell polyomavirus immunohistochemistry has shown an absence of viral large T antigen expression in combined Merkel cell carcinoma as well as select non-Merkel cell carcinoma cutaneous lesions and visceral neuroendocrine tumors. In our series, we aimed to further characterize the frequency and pattern of Merkel cell polyomavirus large T antigen expression by CM2B4 immunohistochemistry in primary and metastatic Merkel cell carcinoma (pure Merkel cell carcinoma and combined Merkel cell carcinoma) and various non-Merkel cell carcinoma lesions from patients with Merkel cell carcinoma, patients without Merkel cell carcinoma, and individuals with altered immune function. Merkel cell polyomavirus large T antigen was detected in 17 (63%) of 27 pure Merkel cell carcinomas and absent in all 15 (0%) combined Merkel cell carcinomas. Furthermore, complete concordance (100%) of Merkel cell polyomavirus large T antigen expression was observed in 10 cases of primary Merkel cell carcinoma and subsequent tumor metastases. We also evaluated 70 non-Merkel cell carcinoma lesions including 15 cases each of pulmonary and gastrointestinal neuroendocrine tumors. All 70 non-Merkel cell carcinoma lesions were negative for Merkel cell polyomavirus by CM2B4 immunohistochemistry, irrespective of any known Merkel cell carcinoma diagnosis and immune status. In summary, our identification of Merkel cell polyomavirus large T antigen expression in a subset of Merkel cell carcinoma and lack of findings in combined Merkel cell carcinomas and non-Merkel cell carcinoma lesions concur with earlier findings and implicate Merkel cell polyomavirus-independent pathogenesis in these cases. Overall, CM2B4 immunohistochemistry appears to be a specific method for Merkel cell polyomavirus detection and has the potential to play an important role in the diagnosis and classification of Merkel cell carcinoma in the future.     

Expression of cyclin D1, Ki-67 and PCNA in non-small cell lung cancer: prognostic significance and comparison with p53 and bcl-2

Uncontrolled cell proliferation is the hallmark of malignant tumours. Thus, the proliferative potential of tumour cells is an important prognostic factor. However, evaluation of the prognostic significance of the expression of proteins involved in regulation of cell proliferation remains controversial. In the present study, expression of Ki-67, PCNA and cyclin D1 was estimated in a group of 89 surgically resected non-small cell lung carcinomas using immunohistochemistry. The results were compared with expression of bcl-2 and p53 and with clinicopathological parameters including patients' survival. Ki-67 and PCNA were found to be moderately and highly expressed in 39% and 44% of the tumours, respectively. There was a strong correlation between Ki67 and PCNA expression. Forty five of 88 tumours (51%) showed overexpression of cyclin D1. Surprisingly, cyclin D1 was mainly localized in the cytoplasm and only a small group of tumours (9/88, 10%) showed nuclear staining as well. Bcl-2 and p53 expression was observed in 69% and 30% of the tumours, respectively. All these markers were found to be independent of clinicopathological parameters, except for Ki-67 and bcl-2 expression, which was associated with squamous cell carcinomas. It is concluded that none of the markers that were studied can be used as an independent prognostic factor, whereas the following combinations of markers may have favourable prognostic value: p53 positivity and low Ki-67 expression, p53 positivity and lack of cyclin D1 expression, bcl-2 positivity and low Ki-67 expression, and lack of cyclin D1 expression and low Ki-67 expression.     

Expression of cyclin kinase inhibitor p27(Kip1) in skin tumours of dogs

Skin tumours (n=148) of epidermal or hair follicle origin were examined immunohistochemically to determine the expression of p27(Kip1)(p27), a cyclin-dependent kinase inhibitor (CDKI), and of Ki-67. In normal skin, a large number of basal cells of the epidermis and hair follicles were positive for Ki-67 and many suprabasal epithelial cells were positive for p27. Most of the hair matrix cells were positive for Ki-67 but negative for p27. Hair papillae were strongly positive for p27. Squamous cell carcinomas had a p27 positive index (PI) significantly lower than that of trichoepitheliomas (P<0.005), basal cell tumours (P<0.05) and intracutaneous cornifying epitheliomas (P<0.001). In contrast, Ki-67 PIs of squamous cell carcinomas and pilomatrixomas were significantly higher than those of trichoepitheliomas, basal cell tumours and intracutaneous cornifying epitheliomas (P<0.01 to P<0.001). No significant difference was observed between the Ki-67 PI values of squamous cell carcinomas and pilomatrixomas. The results suggested that p27 is capable of suppressing cell proliferation in the differentiation of normal canine skin. In spite of being a benign neoplasm, pilomatrixomas had a low p27 expression; this may be a reflection of the proliferative potential of the hair matrix. The expression of p27 may be a useful marker for the analysis of cell kinetics.     

Expression of topoisomerase II and Ki-67 in cervical carcinoma--clinicopathological study using immunohistochemistry

AIM: To study the correlation between the expression of topoisomerase II and Ki-67 antigen and disease outcome in cervical squamous cell carcinomas. EXPERIMENTAL DESIGN: Forty-nine cervical carcinomas, 10 cases of high-grade cervical intraepithelial neoplasia (CIN II-III) and 5 control cervices were stained by monoclonal antibodies for topoisomerase II and Ki-67 (MIB-1 clone). Nuclear counts were correlated with patient age, tumor stage, histological grade and survival. RESULTS: Thirteen patients died of disease, 35 remained free of disease, and one patient was lost to follow up. Ki-67 counts were higher in CIN lesions, when compared to both invasive carcinomas and control cervices. Topoisomerase II counts were comparable for CIN and invasive tumors. No immunoreactivity for topoisomerase was detected in control cases. Neither stage nor grade was associated with nuclear counts using either marker. In multivariate survival analysis, stage (p=0.001), grade (p=0.03) and older patient age (p=0.02) predicted poor survival. Ki-67 counts predicted survival with borderline significance (p=0.07), while topoisomerase II counts were not related to survival. CONCLUSION: Ki-67 and topoisomerase II counts do not appear to have a significant role in the prediction of survival in cervical squamous cell carcinoma.     

Immunohistochemical study of Skp2 and Jab1, two key molecules in the degradation of P27, in lung adenocarcinoma

To clarify the association of the P27 degradation pathway proteins, Skp2 and Jab1, with the development and progression of lung adenocarcinoma (AD), we immunohistochemically investigated Skp2 and Jab1 expression together with P27- and Ki-67-labeling in 110 lung AD and 11 atypical adenomatous hyperplasia (AAH) and analyzed the relationship between the expression of these proteins and the clinicopathological factors. High Skp2 or Jab1 expression was frequent in lung AD (52/110, 47%, and 59/110, 54%, respectively), and high expression of Jab1 was also frequent in AAH (4/11, 36%), while it was not observed in normal bronchiolar epithelium. The P27 labeling index (LI) was reciprocally correlated with high Skp2 and Jab1 expression, and a higher Ki-67 LI was significantly correlated with high Skp2 and Jab1 expression. However, low P27 expression did not correlate with a higher Ki-67 LI. High Skp2 lung AD showed significant correlation with blood and lymphatic vessel invasion, which low P27 expression did not correlate with. Furthermore, high Skp2 expression in lung AD was significantly correlated with a poor outcome for patients. Thus, Skp2 and Jab1 regulate P27 degradation, and might contribute to the development and progression of lung AD through P27-mediated and -unmediated mechanisms.     

p53 but not erbB-2 expression is associated with rapid tumor proliferation in urinary bladder cancer

Tumor proliferation in bladder cancer is associated with tumor behavior. To assess the association between Ki-67 labeling index (LI), p53, and c-erbB-2 overexpression, formalin-fixed tissue samples of 160 patients with transitional cell carcinoma (TCC) of the urinary bladder were studied by immunohistochemistry. Ki-67 LI was strongly associated with tumor stage (P < .0001), tumor grade (P < .0001), and p53 status (P = .0014) but not with erbB-2 overexpression (P > .2). Ki-67 LI was higher in p53-positive tumors (19%) than in p53-negative tumors (14%) when all stages were compared. Ki-67 LI was independent of p53 expression in pTa tumors (p53-positive, 9%; p53-negative, 11%), showing that p53 overexpression alone is not sufficient to induce rapid tumor cell proliferation in pTa tumors. Ki-67 LI also was independent of p53 expression in pT2 to pT4 tumors (p53-positive, 20%; p53-negative, 23%), indicating that p53 expression is not necessary for rapid tumor cell proliferation in advanced stages. However, there was a striking difference in Ki-67 LI between p53-positive pT1 tumors (22.0% ± 8.8 standard deviation [SD]; n = 20) and p53-negative pT1 tumors (9.7 ± 8.3 SD; n = 22; P = .0001). These results suggest that increased proliferation in p53-positive pT1 tumors is caused by additional alterations that occur during tumor progression.     

Topoisomerase II-alpha expression in different cell cycle phases in fresh human breast carcinomas.

Topoisomerase II-alpha (topo II alpha) is the key target enzyme for the topoisomerase inhibitor class of anti-cancer drugs. In normal cells, topo II alpha is expressed predominantly in the S/G2/M phase of the cell cycle. In malignant cells, in vitro studies have indicated that the expression of topo II alpha is both higher and less dependent on proliferation state in the cell. We studied fresh specimens from 50 cases of primary breast cancer. The expression of topo II alpha in different cell cycle phases was analyzed with two-parameter flow cytometry using the monoclonal antibody SWT3D1 and propidium iodide staining. The expression of topo II alpha was significantly higher in the S/G2/M phase of the cell cycle than in the G0/G1 phase in both DNA diploid and DNA non-diploid tumors. In 18 of 21 diploid tumors, and in 25 of 29 non-diploid tumors, >50% of the topo II alpha-positive cells were in the G0/G1 phase. This significant expression of topo II alpha in the G0/G1 phase of the cell cycle may have clinically important implications for treatment efficacy of topoisomerase II inhibitors.     

Expression of topoisomerase II alpha, Ki-67 and p53 in early stage laryngeal carcinomas not featuring vocal cord fixation

AIM: To determine whether topoisomerase II alpha (topoIIa) expression is an additional prognostic marker for less advanced stage laryngeal cancers first treated without surgery. Ki-67 and p53 protein levels were also assessed for comparison. EXPERIMENTAL DESIGN: Formalin-fixed, paraffin-embedded tumor material from 63 cases of squamous cell carcinoma (SCC) of the larynx (glottis, stages 0,1,2) was immunohistochemically stained for topoIIa, Ki-67 (MIB-1) and p53 (DO-7) and the results were compared with clinicopathologic findings. RESULTS: There were 7 stage 0 (TisN0M0), 33 stage I (T1N0M0), and 23 stage II (T2N0M0) SCCs with the TNM classification. Significant differences between carcinomas and normal mucosa were found for the topoIIa-LI, Ki-67-LI, and topoIIa-to-Ki-67 ratio. Regarding histologic grade, a significant difference in topoIIa-to-Ki-67 ratio was evident between well or moderately and poorly differentiated lesions. There were 19 cases of recurrence and 44 cases of nonrecurrence, but no significant differences were found for either of the indices or their ratio. No significant variation with p53 positivity was evident with reference to histologic differentiation, T-factor, clinical course, or proliferation. CONCLUSIONS: The results demonstrate that the topoIIa-to-Ki-67 ratio is a more sensitive parameter reflecting proliferation, for histologic grading of less advanced laryngeal SCCs, than topoIIa- or Ki-67-LIs.