The activation-associated antigen 4F2 predicts patient survival in low-grade B-cell lymphomas

Expression of the activation-associated 4F2 antigen, transferrin receptor and interleukin-2 (IL-2) receptor on suspended cells from 75 biopsied low-grade non-Hodgkin lymphomas (L-NHL) of B-cell origin was correlated to patient survival, clinical prognostic parameters and estimated DNA synthesis. 4F2 antigen expression correlated significantly with poor patient survival, high DNA synthesis and transferrin receptor expression. Transferrin receptor expression was associated with high DNA synthesis and treatment response, but not with patient survival. On the other hand, IL-2 receptor was correlated neither to patient survival nor to other studied markers for cell activation, but seemed to be expressed on certain subsets of lymphomas. We suggest that monoclonal antibody (MAb) against the activation-associated 4F2 antigen could be used to select patients with L-NHL for aggressive chemotherapy.     

Dysregulated CXCR4 expression promotes lymphoma cell survival and independently predicts disease progression in germinal center B-cell-like diffuse large B-cell lymphoma

Abnormal expression of the chemokine receptor CXCR4 plays an essential role in tumor cell dissemination and disease progression. However, the significance of CXCR4 overexpression in de novo diffuse large B cell lymphoma (DLBCL) is unknown. In 743 patients with de novo diffuse large B cell lymphoma (DLBCL) who received standard Rituximab-CHOP immunochemotherapy, we assessed the expression of CXCR4 and dissected its prognostic significance in various DLBCL subsets. Our results showed that CXCR4⁺ patients was associated with male, bulky tumor, high Ki-67 index, activated B-cell-like (ABC) subtype, and Myc, Bcl-2 or p53 overexpression. Moreover, CXCR4⁺ was an independent factor predicting poorer progression-free survival in germinal-center B-cell-like (GCB)-DLBCL, but not in ABC-DLBCL; and in patients with an IPI of ≤2, but not in those with an IPI>2. The lack of prognostic significance of CXCR4 in ABC-DLBCL was likely due to the activation of p53 tumor suppressor attenuating CXCR4 signaling. Furthermore, concurrent CXCR4⁺ and BCL2 translocation showed dismal outcomes resembling but independent of MYC/BCL2 double-hit DLBCL. Gene expression profiling suggested that alterations in the tumor microenvironment and immune responses, increased tumor proliferation and survival, and the dissemination of CXCR4⁺ tumor cells to distant organs or tissues were underlying molecular mechanisms responsible for the CXCR4⁺ associated poor prognosis.     

Prognostic significance of Ki-67 nuclear proliferative antigen, bcl-2 protein, and p53 expression in follicular and diffuse large B-cell lymphoma

We analyzed 104 patients with non-Hodgkin’s lymphoma, follicular or diffuse large-B-cell-type lymphoma, in order to evaluate the correlation between clinical characteristics and immunohistochemical parameters. Immunostaining was performed by means of monoclonal antibodies against Ki-67, bcl-2, and p53 expression. Forty-nine of the patients showed follicular lymphoma. A high expression of bcl-2 was found in 93%, high expression of p53 in 57%, and low expression of Ki-67 in 96%. Follicular lymphoma grade III showed a p53 expression (p=0.07) slightly higher than follicular lymphoma grades I and II, not reaching statistical significance. Follicular lymphoma grades I and II tended to express lower Ki-67 and higher levels of bcl-2 expression than grade III (p=0.06). Fifty-five cases showed diffuse large-B-cell lymphoma. Among them, bcl-2 was absent in 39%, whereas p53 and Ki-67 expression were high in 38%. In the diffuse large-B-cell lymphomas, a high bcl-2 expression correlated with stages III and IV (p=0.03) and involvement of more than one extranodal area (p=0.03). High Ki-67 expression was also associated to extranodal involvement of more than one area (p=0.03). Overall survival of patients did not show statistically significant differences regarding Ki-67, bcl-2, and p53 tumoral expression. Prognostic factors for overall survival in the multivariate analysis were age (p=0.02) and LDH (p=0.003). Time to progression was worse among follicular lymphoma with high p53 expression than with mild/moderate p53 expression (p=0.009).     

MCM2与Ki67在结肠癌中表达的对比研究

目的:探讨微型染色体维持蛋白2(minichromosome maintenance 2 protein,MCM2)与Ki67在结肠癌中的表达及两者表达之间的差异.方法:采用免疫组化染色的方法,分别检测69例结肠癌组织中MCM2,Ki67的表达,计算其标记指数,分析MCM2,ki67在结肠癌中的表达及两者表达之间的差异.结果:69例结肠癌标本均表达MCM2和Ki67,MCM2标记指数高于Ki67,差异具有显著性(P＜0.001).同时显示MCM2,Ki67表达与结肠癌的分化程度相关,MCM2标记指数在各级结肠癌组织之间均有显著差异(P＜0.001),而Ki67标记指数在Ⅱ级和Ⅲ级结肠癌组织之间无统计学差异(P＞0.05).结论:MCM2是较Ki67更好的细胞增殖标记物,可用于对结肠癌的准确分级和判断结肠癌恶性程度高低.     

Radiomic features predict Ki-67 expression level and survival in lower grade gliomas

To investigate the radiomic features associated with Ki-67 expression in lower grade gliomas and assess the prognostic values of these features. Patients with lower grade gliomas (n?=?117) were randomly assigned into the training (n?=?78) and validation (n?=?39) sets. A total of 431 radiological features were extracted from each patient. Differential radiological features between the low and high Ki-67 expression groups were screened by significance analysis of microarrays. Then, generalized linear analysis was performed to select features that could predict the Ki-67 expression level. Predictive efficiencies were further evaluated in the validation set. Cox regression analysis was performed to investigate the prognostic values of Ki-67 expression level and Ki-67-related radiological features. A group of nine radiological features were screened for prediction of Ki-67 expression status; these achieved accuracies of 83.3% and 88.6% (areas under the curves, 0.91 and 0.93) in the training and validation sets, respectively. Of these features, only spherical disproportion (SD) was found to be a prognostic factor. Patients in the high SD group exhibited worse outcomes in the whole cohort (overall survival, p?<?0.0001; progression-free survival, p?<?0.0001). Ki-67 expression level and SD were independent prognostic factors in the multivariate Cox regression analysis. This study identified a radiomic signature for prediction of Ki-67 expression level as well as a prognostic radiological feature in patients with lower grade gliomas.     

High expression of DNA topoisomerase IIalpha and Ki-67 antigen is associated with prolonged survival in glioblastoma patients

Assessment of tumour cell proliferation in glioblastoma (GB) has been a topic of considerable research interest over the past decade. However, the correlation of tumour proliferation and patient outcome has yielded controversial results. In this study, we examined immunohistochemically, using paraffin-embedded tissue, the expression of the proliferation-related markers DNA topoisomerase IIalpha (TIIalpha) and Ki-67 antigen in a cohort of 114 GB patients treated consecutively with surgery and radiochemotherapy, and correlated the expression with patient outcome. The TIIalpha labelling index (LI) ranged between 5.2 and 87.2% (median: 25.6%). Survival analysis disclosed an association between high TIIalpha expression levels and prolonged survival (P=0.040, log-rank test). TIIalpha expression correlates closely with Ki-67 labelling index (R=0.927, P<0.001), which itself is predictive of patient survival (P=0.044). However, in multivariate analysis, only the Karnofsky performance status remained predictive of patient survival. We conclude that high expression of TIIalpha and Ki-67 appears to be associated with a prolonged survival in our cohort of GB patients.     

Relationship between tumour shrinkage and reduction in Ki67 expression after primary chemotherapy in human breast cancer.

The association between tumour shrinkage and reduction in kinetic cell activity after primary chemotherapy in human breast cancer is still a matter of investigation. 157 patients with T2-4, N0-1, M0 breast cancer received primary chemotherapy consisting of either the CMF regimen + tamoxifen (the first consecutive 76 cases) or the single agent epirubicin (the subsequent 81). Ki67, p53, bcl2, c-erbB2 and steroid hormone receptors were evaluated immunohistochemically in tumour specimens obtained before chemotherapy and at surgery. Tumour shrinkage of >50% occurred in 72.4% of patients. Ki67 expression significantly decreased after chemotherapy; the reduction correlated with tumour response in both univariate (P < 0.005) and multivariate analysis (P = 0.02). p53, bcl-2, steroid hormone receptor and c-erbB2 immunostaining were scarcely affected. Baseline bcl2 (P = 0.04) and c-erbB2 (P = 0.02) were directly and inversely associated with the reduction in Ki67 immunostaining, respectively. Baseline p53 expression (P < 0.01) was directly related with Ki67 expression at residual tumour, whereas oestrogen receptor expression (P < 0.001) was inversely related. Ki67 at residual tumour was a better predictor for relapse-free survival (RFS) than baseline Ki67. Clinical response (P < 0.03), but not reduction in Ki67, was a significant independent predictor for disease recurrence. Chemotherapy was found to induce tumour shrinkage and to reduce the number of cells in the cell cycle, but its effect on tumour biology/aggressiveness was minimal. Reduction in Ki67 immunostaining correlated with clinical response but failed to be related to RFS. Ki67 expression at surgery rather than at baseline appears to be a better predictor for disease relapse.     

B7-2 expression above a threshold elicits anti-tumor immunity as effective as interleukin-12 and prolongs survival in murine B-cell lymphoma

The costimulatory molecule, B7-2, is expressed by various lymphomas, but this level of expression is not sufficient to generate effective anti-tumor immunity in vivo. To determine whether up-regulated expression of the costimulatory molecule, B7-2, leads to more effective anti-tumor immunity in vivo, the A20 murine model of B-cell lymphoma was used. A20 tumor cells express major histocompatibility complex (MHC) I and II molecules and moderate constitutive levels of B7-2. While B7-1 and B7-2 have been introduced into tumor cells lacking these molecules, studies have not been conducted to determine whether tumors that constitutively express B7-1 or B7-2 can be made more immunogenic by increasing the expression of these molecules. In this report, A20/B7-2 transfectants expressing greater levels of B7-2 were rejected in syngeneic mice, and systemic immunity against the A20 parental cells was generated. Treatment with the A20/B7-2 variant cells significantly improved the survival of tumor-bearing mice. Coinjection with IL-12 secreting variants did not further augment the anti-tumor immunity observed for B7-2 therapy alone. Both CD8(+) T cells and natural killer (NK) cells mediated the anti-tumor immune response observed in A20/B7-2 immunized mice. In mice that developed tumors after immunization with the A20/B7-2 variant cells, resected tumor cells were shown to express lower levels of B7-2 than the transfected variants. These results suggest that the level of costimulation is important for the generation of anti-tumor immunity and for host survival. In addition, tumors appear to be able to evade the immune response by downregulating the expression of B7-2 below a threshold level.     

Aneuploidy and high expression of p53 and Ki67 is associated with neoplastic progression in Barrett esophagus

Unless detected at an early stage, esophageal adenocarcinoma (EAC) has a poor prognosis. Changes in cellular DNA content and expression levels of p53 and Ki67 in Barrett esophagus (BE) are associated with the development EAC and might serve as markers to identify EAC at an early stage. The aim of this study was to examine the presence of these three markers in various steps of neoplastic progression in BE towards EAC. Dysplasia was graded in 212 biopsy sets taken during follow-up upper endoscopy in 27 patients in whom ultimately high-grade dysplasia (HGD) or EAC was detected. Ploidy status was determined by flow cytometry, whereas Ki67 and p53 expression were determined by immunohistochemistry. Smoothing splines were used to analyze trends in time. We found an increasing fraction of Ki67 overexpression and, to a lesser extent, abnormal DNA content in biopsies closer to the time-point of detecting HGD/EAC in BE, suggesting the potential value of these biomarkers in identifying patients at increased risk of progression towards HGD/EAC. Accumulation of p53 was seen several years before development of HGD/EAC, and may therefore be an early marker in BE at a stage when dysplasia is not yet detected. A prospective follow-up study is needed to confirm these findings.     

R-CHOP regimen can significantly decrease the risk of disease relapse and progression in patients with non-germinal center B-cell subtype diffuse large B-cell lymphoma

To further explore the role of rituximab when added to the CHOP-like regimen in the treatment of immunohistochemically defined non-germinal center B-cell subtype (non-GCB) diffuse large B-celllymphoma (DLBCL), 159 newly diagnosed DLBCL patients were studied retrospectively based on the immunohistochemical evaluation of CD10, Bcl-6, MUM-1, and Bcl-2. Altogether, 110 patients underwent the CHOP-like regimen, and rituximab was added for the other 49 patients. Cox regression analysis showed that compared with the CHOP-like regimen, the rituximab-based regimen (R-CHOP regimen)significantly decreased the risk of disease relapse and progression in CD10-negative patients (P=0.001),Bcl-6-negative patients (P=0.01), and MUM-1-positive patients (P=0.003). The risk of disease relapse in patients with non-GCB subtype (P=0.002) also decreased. In contrast, patients with the opposite immunohistochemical marker expression profile and GCB subtype did not benefit from treatment with the R-CHOP regimen. In addition, non-GCB subtype patients had a significantly higher expression rate of Bcl-2 than GCB subtype patients (P=0.042). Although univariate analysis found that both Bcl-2-positive and-negative patients had significantly higher event-free survival rates with the R-CHOP regimen, only Bcl-2 positivity (P=0.004) maintained significance in the Cox regression analysis. We conclude that the addition of rituximab can significantly improve the prognosis of patients with non-GCB subtype DLBCL, which is closely related to the expression of CD10, Bcl-6, MUM-1, and Bcl-2.     

Transferrin receptor and B-lymphoblast antigen — their relationship to DNA synthesis,histology and survival in B-cell lymphomas

The reactivity of two monoclonal antibodies indentifying antigens related to B-cell activation, B3/25 (the transferrin receptor) and BB-1 (the B-lymphoblast-1-antigen), was examined on cell suspensions from 75 cases of monoclonal B-cell lymphomas. The expression of B3/25 antigen was correlated to DNA synthesis as measured by spontaneous ³H-thymidine incorporation (p= 0.0003) and histopathologically high-grade malignancy (p= 0.00003). Furthermore, B3/25 expression was associated with survival since the patients with B3/25-negative tumors survived longer than those with B3/25-positive tumors (p= 0.018). B3/25 expression also defined a larger group of patients with shorter survival than did histopathology alone, 28 cases versus 16 cases, respectively. On the other hand, the BB-1 antigen did not reveal an association with DNA synthesis, high-grade malignancy or survival. However, the findings indicated that BB-1 may be related to B-cell maturation/differentiation.     

Pre-treatment hormonal receptor status and Ki67 index predict pathologic complete response to neoadjuvant trastuzumab/taxanes but not disease-free survival in HER2-positive breast cancer patients

Trastuzumab-containing neoadjuvant chemotherapy achieves a pathologic complete response (pCR) rate of about 40?% in HER2-positive breast cancers, and pCR predicts better survival. A cohort of 102 consecutive Chinese HER2-positive stage II/III patients with neoadjuvant trastuzumab/taxanes were retrospectively analyzed, to evaluate the role of hormonal receptor (HR) status and Ki67 index, along with other parameters, in pCR and survival prediction. pCR rate of the cohort was 44.1?% (45/102). Fifty-three patients were HR-positive and 49 were HR-negative. Median Ki67 index was 40?%, and 49 patients had a high Ki67 index (>40?%) whereas 53 had a low Ki67 index (??40?%). HR status and Ki67 index were confirmed as the only two parameters associated with pCR in multivariate analysis (hazard ratio?=?2.952; 95?% CI, 1.227?C7.105; P?=?0.016 for HR status and hazard ratio?=?2.583, 95?% CI 1.107?C6.026, P?=?0.028 for Ki67 index). Patients with coexisting HR-negative and high Ki67 index had higher pCR rate (69.2?%), compared to those with either HR-negative alone or high Ki67 alone (hazard ratio?=?3.038; 95?% CI, 1.102?C8.372; P?=?0.029), and to those with coexisting HR-positive and low Ki67 index as well (hazard ratio?=?7.071; 95?% CI, 2.150?C23.253; P?=?0.001). In a median follow-up duration of 25.9?months, 11 disease-free survival events (DFS) were recorded. pCR predicted better DFS (log rank P?=?0.018) and was the only significant factor in Cox regression analysis (hazard ratio?=?0.184; 95?% CI, 0.038?C0.893; P?=?0.036). Our study indicates that HR status and Ki67 index are predictors for pCR but not for DFS in HER2-positive patients with neoadjuvant trastuzumab/taxanes, which deserves further investigations.     

Bcl-2 gene expression as a predictor of outcome in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is an aggressive lymphoma with a 5-year survival rate of 35%-60%. Various clinical factors included in the International Prognostic Index have failed to identify the patients with DLBCL who will not benefit from the standard R-CHOP (cyclophosphamide/doxorubicin/vincristine/prednisone plus rituximab) treatment regimen. Bcl-2 has been implicated in conferring resistance to chemotherapy in non-Hodgkin's lymphoma and is therefore a candidate prognostic marker in DLBCL. To identify the correlation between Bcl-2 expression and response to rituximab-containing treatment regimens, histologic materials were analyzed from 292 elderly patients with confirmed DLBCL. Of these, 155 patients had received R-CHOP (53%) and 137 had received CHOP (47%). One hundred ninety-three patients (66%) were found to express high levels of Bcl-2 protein in > 50% of the tumor cells. Of the 193 Bcl-2-positive patients, the patients who received R-CHOP had a better 5-year overall rate than patients treated with CHOP (56% vs. 42%; P = 0.01), whereas in the patients with Bcl-2-negative disease, there was no statistically significant difference in the 5-year overall survival rates between the R-CHOP and CHOP regimens (58% vs. 52%; P = 0.6). Therefore, the addition of rituximab to the standard chemotherapy regimen seems to have overcome the Bcl-2-associated resistance to chemotherapy.     

Prolactin/androgen-inducible carboxypeptidase-D increases with nitrotyrosine and Ki67 for breast cancer progression in vivo,and upregulates progression markers VEGF-C and Runx2 in vitro

Purpose

Carboxypeptidase-D (CPD) cleaves C-terminal arginine (Arg) to produce nitric oxide (NO). Upregulation of CPD and NO by 17β-estradiol, prolactin (PRL), and androgen increases survival of human breast cancer (BCa) cells in vitro. To demonstrate similar events in vivo, CPD, nitrotyrosine (NT, hallmark of NO action), androgen receptor (AR), prolactin receptor (PRLR), and phospho-Stat5a (for activated PRLR) levels were evaluated in benign and malignant human breast tissues, and correlated with cell proliferation (Ki67) and BCa progression (Cullin-3) biomarkers.

Methods

Paraffin-embedded breast tissues were analyzed by immunohistochemistry (IHC). BCa progression markers in human MCF-7 and T47D BCa cell lines treated with NO donor SIN-1 or PRL, ±CPD inhibitors were analyzed by RT-qPCR and immunoblotting.

Results

IHC showed progressive increases in CPD, NT, Ki67, and Cullin-3 from low levels in benign tissues to high levels in ductal carcinoma in situ, low-grade, high-grade, and triple-negative BCa. CPD and NT staining were closely associated, implicating CPD in NO production. Phospho-Stat5a increased significantly from benign to high-grade BCa and was mostly nuclear. AR and PRLR were abundant in benign breast and BCa, including triple-negative tumors. SIN-1 and PRL increased VEGF-C and Runx2, but not Cullin-3, in BCa cell lines. PRL induction of VEGF-C and Runx2 was inhibited partly by CPD inhibitors, implicating NO, produced by PRL-regulated CPD, in BCa progression.

Conclusions

The CPD-Arg-NO pathway contributes to BCa progression in vitro and in vivo. PRL/androgen activation of the pathway support combined AR and PRLR blockade as an additional therapy for BCa.

     

Changes in the expression of idiotype antigen on murine B-cell lymphoma after hyperthermia alone and in combination with interferon and tumour necrosis factor.

The effect of interferon (IFN) and tumour necrosis factor (TNF), either alone or combined with hyperthermia, on cell proliferation and expression of idiotype antigen on a murine B-cell lymphoma has been studied. Incubation with same doses of IFN-alpha and IFN-gamma reduced cell proliferation to the same extent. Hyperthermia potentiated the antiproliferative activity of IFN-alpha and IFN-gamma. Pretreatment with IFN-gamma induced a synergistic response with heat, while IFN-alpha and heat had an additive effect. Tumour necrosis factor (TNF) alone did not affect cell proliferation, nor did TNF modify the heat-induced delay in cell growth. The quantitative expression of surface idiotype antigen was studied by flow cytometry using an anti-idiotype monoclonal antibody (MAb). Heat reduced the expression of idiotype antigen approximately 50%. The duration of the reduction depended on the heat-dose. Recovery of antigen expression correlated with recovery of cell growth, and 2-5 days after the treatment antigen expression returned to the normal level for untreated cells. IFN-gamma and TNF increased antigen expression (30-50%) which lasted for 4-6 days after treatment. When cells were incubated with IFN-gamma or TNF for 2 days prior to hyperthermia, the increase in antigen expression was observed immediately after heating, but by the following day, antigen expression was similar to that after heat treatment alone. Expression of idiotype antigen recovered within 2-5 days to the same values as after heat treatment alone. IFN-alpha alone or combined with hyperthermia did not have any significant effect on antigen expression.     

Skp2 expression is associated with high risk and elevated Ki67 expression in gastrointestinal stromal tumours

Background  

Gastrointestinal stromal tumors (GIST) exhibit an unpredictable clinical course and can rapidly progress to lethality. Predictions about the biological behavior of GIST are based on a number of canonical clinical and pathologic parameters whose validity in distinguishing between a benign and a malignant tumour is still imperfect. The aim of our study was to investigate the role of morphologic parameters and expression of cells cycle regulators as prognosticators in GIST.     

Ki-67 expression and residual tumour (R) classification are associated with disease-free survival in desmoid tumour patients

BACKGROUND: In order to evaluate prognostic factors in the long-term survival of desmoid tumour patients, analysis of clinicopathological, immunohistochemical and follow-up data was performed. PATIENTS AND METHODS: Between 1969 and 1998, 54 patients underwent resection of aggressive fibromatosis (desmoid) and 33 of them (10 patients with FAP and 23 sporadic) were followed-up with a median time of 130 months (range 10-355 months). Additionally, immunohistochemical analysis of the desmoid tumours using Ki-67 was performed. RESULTS: In univariate analysis, curative resection (R0) (p<0.001) and low proliferation of Ki-67 (p=0.002) were of significant positive prognostic value concerning disease-free survivaL R0 and absence of Ki-67 staining were significantly associated with each other (p=0.004). CONCLUSION: Ki-67 seems to serve as a predictive marker concerning disease-free survival of desmoid tumour patients. In patients presenting with Ki-67 positive desmoids, which are unlikely to be resected in a curative manner, alternative treatment (e.g. sulindac) may be preferable.     

Transferrin receptor and 4F2 expression by NK-sensitive and NK-resistant tumour cell lines

Upon stimulation with a phorbol ester and known tumour promoter,12-O-tetradecanoylphorbol-13-acetate (TPA), the human erythroleukemiaK562 cell line, a standard target for human natural killer (NK)cells, shows a significant reduction in expression of transferrinreceptors (TfR) and becomes resistant to NK-mediated cytolysis.Prompted by the initial finding that expression of TfRs by K562cells correlates with target sensitivity to NK cytotoxicity,we have investigated the role of two proposed NK-target structures,the TfR and 4F2 molecule in three other tumour cell lines whichvary in their susceptibility to NK activity. We report thatsimilar to K562 cells, MOLT 4, Raji and HL60 cells demonstratephorbol-ester-induced down-regulation of TfR expression. Theexpression of TfRs alone does not determine target sensitivity.However, TfRs are probably located close to the NK-target structurein NK-sensitive cell lines. Based on the properties of phorbolester induction, it is possible that the NK-target moleculeis down-regulated in response to phorbol ester induction ina similar, if not identical manner to that of the TfR; thus,rendering NK-sensitive cells resistant to NK killing, afterTPA exposure. Conversely, the target molecule is probably upregulatedin MOLT 4 cells after TPA treatment as indicated by the acquiredsensitivity of these cells to NK-mediated cytolysis. The expressionof 4F2 molecules was not influenced by TPA treatment and doesnot correlate with NK sensitivity.     

Aberrant expression of minichromosome maintenance protein-2 and Ki67 in laryngeal squamous epithelial lesions

Histological classification of laryngeal epithelial lesions is highly subjective, and methods of cytological detection are not well developed. Improved determination of aberrant cell cycle entry may allow increased objectivity in histological assessment and enable the development of less invasive diagnostic cytology tests. Sections of normal larynx (n=10), laryngeal dysplasia (n=20) and laryngeal squamous cell carcinoma (SCC) (n=10) were classified according to the Ljubljana classification and stained for markers of cell cycle entry, minichromosome maintenance protein-2 (Mcm-2) and Ki67. Expression patterns were compared using double labelling confocal microscopy. There was a correlation between Mcm-2 and Ki67 labelling indices (rho=0.93; 95% CI [0.84, 0.97]) and both markers showed increased expression from normal epithelium to SCC (Mcm-2, P=0.001; Ki67, P=0.0002). Importantly, there was minimal expression of Mcm-2 or Ki67 in the most superficial layers of normal larynx and abnormal or atypical hyperplasia, in contrast to carcinoma in situ and SCC. Clusters of Mcm-2/5-positive cells were present in cytological preparations from SCC, but not from those showing atypical hyperplasia or inflammation in non-neoplastic tissue. Minichromosome maintenance protein-2 staining may increase the objectivity and reliability of histological grading of laryngeal epithelial lesions. Laryngeal brushings, combined with immuno-enhanced liquid-based cytology, could be useful, as a less invasive approach, to the detection of laryngeal malignant and premalignant lesions.