Bone marrow biopsy in chronic lymphocytic leukemia: a review of its prognostic importance

In recent years important advances have been made in predicting the survival of patients with chronic lymphocytic leukemia (CLL). Other prognostic factors in addition to clinical staging systems have proved to be of value. Among them, bone marrow biopsy has emerged as a particularly useful prognostic tool. Patients with nondiffuse bone marrow involvement survive longer than those with diffuse involvement. This parameter is useful for subclassifying clinical stages in low- (nondiffuse patterns) and high- (diffuse patterns) risk groups. The use of a combined clinicopathological staging system for CLL seems advisable.     

PCR-based clonality assessment in patients with lymphocytic leukaemias: a single-institution experience

PCR-based clonality testing can be performed in all lymphoproliferations by analysing gene rearrangements of antigen receptors, rearrangements that are unique for each kind of lymphocyte. Reactive lymphoproliferations have polyclonally rearranged Ig/TCR genes, whereas malignant proliferations (leukaemias and lymphomas) show clonal rearrangements. The aim of this study was to assess the clinical benefits of clonality testing with previously evaluated consensus primers in leukaemia patients. The study included peripheral blood and bone marrow samples of 67 leukaemia patients (32 B-CLL, 24 B-ALL and 11 T-ALL). Clonality testing was based on PCR amplification of rearranged IgH and TCR genes. During diagnosis, monoclonal pattern was found in all analysed B-CLL and T-ALL samples. Testing in B-ALL patients showed positive results in all bone marrow and one peripheral blood samples. Results of clonality testing in B-CLL patients during follow-up were concordant between peripheral blood and bone marrow. Obtained results corresponded to clinical course in all but one patient. In B-ALL group, results of molecular testing in peripheral blood and bone marrow confirmed remission estimated according to clinical criteria in all except one patient. Before any clinical sign of relapse, monoclonal pattern was found in six/seven patients by bone marrow and in three/seven patients by peripheral blood analysis, respectively. Results of molecular monitoring in T-ALL patients did not confirme clinical evaluation in two patients. Obtained results indicate high accuracy of re-evaluated primers for clonality assessment in ALL and CLL patients at the time of diagnosis. Results of clonality testing in B-ALL patients indicate that bone marrow analysis has higher sensitivity compared to analysis of peripheral blood.     

Differential bone marrow homing capacity of VLA-4 and CD38 high expressing chronic lymphocytic leukemia cells

Background

VLA-4 and CD38 predict a poor clinical outcome in chronic lymphocytic leukemia (CLL). We used CLL samples with discordant VLA-4/CD38 risk to address their individual roles in human bone marrow infiltration (BM), CLL cell homing to murine BM, and in supportive CLL cell-stromal cell interactions.

Methods

VLA-4, CD38, and Ki-67 expression was measured in CLL cells from peripheral blood (PB) and bone marrow (BM) aspirates. CLL BM infiltration rates, routinely determined by Pathology, were correlated to VLA-4 and CD38 expression. Short-term homing capacity of CLL cells was evaluated by adoptive transfer experiments. CLL cell viability and adhesion in stromal cell co-culture was determined.

Results

About 20% of CLL samples in our cohort displayed discordant VLA-4 and CD38 risk, with either high VLA-4 and low CD38 risk or vice versa. Using particularly such samples, we observed that VLA-4, and not CD38, was responsible for recirculation of CLL cells to murine BM. Human BM infiltration was also significantly higher in patients with high VLA-4 risk but not high CD38 risk. However, both molecules acted as independent prognostic markers. While both VLA-4 and CD38 expression were increased in BM-derived CLL cells, and VLA-4+ and CD38+ subpopulations showed enriched Ki-67 expression, VLA-4 did not contribute to CLL cell protection by stromal cells in vitro.

Conclusions

Our data argue for a prominent role of VLA-4 but not CD38 expression in the homing of CLL cells to BM niches and in human BM infiltration,but only a limited role in their protection by stromal cells.     

Bone marrow histopathologic patterns and immunologic phenotype in B-cell chronic lymphocytic leukaemia

The present work analyzes the clinicobiological and immunological characteristics - the latter hitherto unexplored - of the different bone marrow histopathological patterns of the B-cell chronic lymphocytic leukaemia (B-CLL). In addition, we studied whether any or some of these parameters were able to predict the probability of a particular pattern of bone marrow involvement appearing. Of the 100 B-CLL cases studied 41 had a diffuse pattern and 59 were non-diffuse - interstitial 27, nodular 11 and mixed 21 -. Neither clinical nor immunological differences were observed among the distinct non-diffuse patterns. The patients in the diffuse group displayed an increased incidence of mu+ isotype and a higher proportion of HLA-DR and HAN-PC 1 positive cells while, conversely, reactivity with the FMC 8 McAb was lower. In addition, patients with a diffuse pattern of BM involvement displayed features of a more extensive disease: a higher incidence of adenopathies (p less than 0.05), hepatomegaly (p less than 0.01), splenomegaly (p less than 0.01), anaemia (p less than 0.01) and thrombopenia (p less than 0.01) as well as higher levels of peripheral blood lymphocytosis (p less than 0.05) and a higher percentage of BM lymphocytic infiltration (p less than 0.001). Multiple regression analysis showed that thrombopenia and splenomegaly were the two most important features in predicting the probability of a diffuse pattern.     

Ki-67 and AgNOR proliferative markers as diagnostic adjuncts to fine needle aspiration cytology of thyroid follicular lesions

OBJECTIVE: To differentiate hyperplastic nodules (HPN), follicular adenoma (FA) and follicular carcinoma (FCA) of the thyroid by cytomorphologic features combined with argyrophilic nucleolar organizer regions (AgNORs) and Ki-67 proliferative markers on fine needle aspiration cytology. STUDY DESIGN: Cytomorphologic patterns, along with two proliferation markers, Ki-67 and AgNORs, in fine needle aspirates of 123 histologically confirmed cases of thyroid follicular lesions, including 39 hyperplastic nodules, 70 follicular adenomas and 14 cases of follicular carcinomas, were recorded. RESULTS: Mean AgNOR (mAgNOR) counts and Ki-67 labelling index (LI) were consistently higher in FCA in comparison to FA and HPN irrespective of the cytologic patterns in fine needle aspiration smears. Between benign and malignant lesions, an overlap of 1.83% at the cutoff point of 4.0 was observed in cases of mAgNORs, whereas it was 11.09% at a cutoff of 5.0 in cases of Ki-67 LI. CONCLUSION: mAgNOR counting in fine needle aspiration smears is more sensitive, simple and cost effective as compared to Ki-67 LI for differentiating between benign and malignant thyroid follicular neoplasms.     

The CD38 ectoenzyme family: advances in basic science and clinical practice

One aim of this session given at the Torino CD38 Meeting in June, 2006 was to review the role of CD38 in B-cell Chronic Lymphocytic Leukemia (B-CLL), and its potential as a therapeutic target. CD38(high) B-CLL cases show activated phenotypic features as compared with CD38(low) cases. Moreover, a greater percentage of Ki-67 and telomerase activity is documented among CD38(high) cases. Also, CD38 is not merely a negative prognostic marker in B-CLL, but also a key element in the pathogenetic network underlying the disease. A large series of B-CLL cases investigating the CD38 expression on bone marrow B-cells identified CD38 value <10% as the cut-off predicting a longer time to treatment. However, neither CD38 nor ZAP-70 by themselves or in combination were able to anticipate IgVH mutational status. Transferring these findings into clinical ground, 3 groups of B-CLL cases were identified with significantly different clinical courses: i.e., low-risk (no negative prognostic factor), intermediate-risk (1 negative prognostic factor) and high-risk (2-3 negative prognostic factors) patients. Altogether these results suggest that: i) CD38-expressing cells present not only an activation status, but also a different stage differentiation with a more repeated turnover; ii) CD38 contributes to controlling a signaling pathway that confers to B-CLL cells an increased proliferative potential, enhancing aggressiveness of this variant; iii) different CD38 cut off values should be considered for peripheral blood and bone marrow; iv) CD38 seems to independently contribute to prognostic stratification of B-CLL.     

PCNA Ki-67 dissociation in childhood acute lymphoblastic leukaemia. An Immunofluorescent Laser Confocal Scanning Microscopical study.

Cell proliferation rates of diagnostic marrow aspirate cells of 21 children with Acute Lymphoblastic Leukaemia and 16 controls were compared using immunocytochemical labelling of PCNA and Ki-67 antigen as assessed by Confocal Laser Scanning Microscopy. The results showed an unexpected, highly significant degree of dissociation between PCNA and Ki-67 expression in ALL blasts. The PCNA labelling indices of ALL patients were significantly increased (mean 44, range 24-77) compared with normal reactive marrow cells (mean 13.8, range 4-26) (p<0.000001, Mann Whitney U two tailed test), suggesting an abnormal commitment to proliferation. Ki-67 expression was raised to a lesser extent in ALL cells (mean 14.8, range 1.2-35) when compared to non-malignant proliferations (mean 6.6, range 1.7-25) (p < 0.02). PCNA/Ki-67 LI ratios in ALL (mean 7, range 1.1-35) were higher than in controls (mean 2.7, range 1.04-6.5, p<0.09). As cell proliferation rates actually achieved in the bone marrow do not differ as strongly as suggested by the extreme difference in PCNA labelling, a pathological dissociation of PCNA / Ki-67 expression exists, suggesting immortalisation.     

Immunohistochemical analyses of cell cycle-related proteins, apoptosis, and proliferation in pituitary adenomas.

To analyze the cell cycle regulatory mechanisms in the growth of pituitary adenomas, we investigated immunohistochemically the expression of the cell cycle-related proteins cyclin A and p27 in 48 pituitary adenomas. The frequency of apoptosis and the proliferative potential were also examined. The percentage of apoptotic cells was evaluated by immunohistochemical analysis using the anti-single-strand DNA antibody. The proliferative potential was assessed using the anti-Ki-67 antibody. The mean cyclin A labeling index (LI) for the non-recurrent group was 1.03% and for the recurrent group 2.31%. A positive linear correlation between cyclin A LI and Ki-67 LI was found. The mean p27 LI for the non-recurrent group was 67.4% and for the recurrent group 47.0%. There were significant differences in cyclin A LI and p27 LI between the non-recurrent group and the recurrent group. The mean apoptotic rate for the non-recurrent group was 0.87% and for the recurrent group 1.05%. There was no significant difference. Multivariate regression analysis revealed that high cyclin A LI and high Ki-67 LI were significant factors for shorter progression-free survival. The results suggest that the cyclin A LI is a useful prognostic factor in pituitary adenomas. (J Histochem Cytochem 49:1193-1194, 2001)     

Ki-67 labelling index in human brain tumours

The proliferative potential in 157 brain tumours was investigated using Ki-67 labelling index (Ki-67LI). There were 46 patients with low grade gliomas (Al & All), 82 with high grade gliomas (AIII & AIV) and 29 with metastatic tumours. Tumour fragments used for assessment of Ki-67LI were fixed in formalin. Ki-67 antigen was visualised on paraffin sections using DAKO Rabbit Anti-Human Ki-67 antigen. The Ki-67LI was calculated as the percentage of Ki-67 labelled cells. The tumours showed variability in the Ki-67LI values. Significantly higher mean Ki-67LI was found for highly malignant (AIII & AIV) than for low grade gliomas (Al & All). For metastatic tumours, the mean values of Ki-67LI were significantly higher than for gliomas. Moreover, Ki-67LI of metastatic tumours were significantly higher than for high grade gliomas.     

Diagnostic and prognostic value of immunohistological bone marrow examination: results in 212 patients with lymphoproliferative disorders

Cryostat sections of 246 consecutive bone marrow biopsies from 212 patients with lymphoproliferative disease were investigated using a panel of monoclonal antibodies (MOAb's) and an immunoperoxidase technique. Bone marrow involvement was demonstrated by immunohistological examination in 121/160 patients (76%) with non-Hodgkin lymphomas (NHL) and 16/23 patients (70%) with plasma cell malignancies; the definite immunological diagnosis could be performed in 77% and 88%, respectively. Reactivity with the MoAb Ki-67 correlated with clinical parameters: in all cases exhibiting more than 5% positive cells an unfavourable course was seen, independent of the histological subtype. Another MoAb of potential prognostic relevance is KiM 4 b, which reacts with follicular dendritic cells (FDC). Besides the presence of FDC in germinal center tumors (CB/CC and CC-NHL) we found FDC in a minority of cases with B-CLL (5/44) and IC lymphoma (4/18). In the latter group 3/4 patients showed a favourable clinical course (vs 2/14 without FDC). The MoAb Tü 1 could discriminate between the lymphoplasmocytoid (11/12 positive) and the lymphoplasmocytic (0/6 positive) subtype of IC lymphoma and has proven of diagnostic importance. Expression of IL-2 receptors, detected by MoAb anti-Tac (CD 25), was demonstrated on leukemic cells from patients with hairy cell leukemia (100%), B-CLL (82%), IC (61%), CC (50%) and CB/CC lymphoma (50%). A considerable number of reactive T-lymphocytes (5%-60% of tissue cells) were identified among the neoplastic B cells with a predominance of CD4+ cells in most cases with NHL, whereas the CD4+/CD8+ ratio was significantly lower in myelomas and non-infiltrated bone marrows. The potential meaning of these findings is discussed. The immunohistological bone marrow analysis represents an important additional method in the diagnostic procedures of lymphoproliferative diseases involving the bone.     

Genetic instability promotes the acquisition of chromosomal imbalances in T1b and T1c breast adenocarcinomas.

In order to evaluate biological and genetic properties of early breast carcinomas we analyzed microdissected tissue from 33 primary breast carcinomas stage T1b and T1c with respect to the nuclear DNA content, the expression pattern of Ki-67, cyclin A, p27KIP1, p53 and p21WAF1, and chromosomal gains and losses. The results show that T1b carcinomas (6-10 mm, n=17) were frequently near-diploid (53%) with low proliferative activity and staining patterns of p53 and p21WAF1 that suggest the presence of wild type protein. The majority (12/16) of the T1c tumors (11-20 mm), however, was aneuploid, and proliferative activity and p53 expression were increased. Larger tumor size correlated with an increasing number of chromosomal copy number changes and in particular with regional amplifications. High level copy number increases (amplifications), however, were found exclusively in the aneuploid tumors. Amplification events correlated with elevated cyclin A and reduced p27 expression, respectively. Our results suggest that the sequential acquisition of genomic imbalances during tumor progression is accelerated in aneuploid tumors, and may contribute to the increased malignancy potential.     

Ki-67 expression and BrdUrd incorporation as markers of proliferative activity in human prostate tumour models

Abstract. The validity of the use of the monoclonal antibodies Ki-67 and anti-BrdUrd to evaluate proliferative activity of human prostate tumour models was studied. Growth of the transplantable PC-82 and PC-EW prostate tumours, as assessed by tumour volume measurements, was significantly correlated with the proliferative activity as reflected by BrdUrd incorporation into DNA ( r = 0.64 and r = 0.78, respectively). The proliferative activity of PC-82 tumours detected by Ki-67 antigen expression paralleled the pattern observed with BrdUrd ( r = 0.51) and a significant correlation ( r = 0.60) between the results obtained with both markers was found. In growing PC-82 and PC-EW tumours only small variations in the Ki-67 and BrdUrd indices were observed. In contrast, Ki-67 expression in regressing PC-82 tumours varied considerably (2.7 ± 2.2%). The BrdUrd index in regressing PC-32 tumours showed less variation (1.3 ± 0.2%), but part of the BrdUrd-positive cells were found in the stromal (murine) part of the regressing tissue. It is concluded that the Ki-67 and BrdUrd proliferation markers are reliable parameters to monitor changes in growth of prostate tumour lines, but that in slow growing or regressing tumours Ki-67 and BrdUrd data should be interpreted with caution.     

Quantitative cytological assessment of Ki67 and AgNORs using computer-digitized image analysis of four clinicopathological breast lesions

Analysis of silver-stained proteins associated with nucleolar organiser regions (AgNORs) is proposed as a marker of cellular proliferation. This study describes the application of AgNORs and Ki67 in breast lesions. Sixty-one cases including fibroadenoma (FA), fibrocystic disease (FCD), ductal carcinoma in situ (DCIS) and invasive carcinoma (IC) were studied by image analysis to evaluate quantitative changes in AgNORs in both Ki67-positive, and Ki67-negative smears. The Ki67 index was assessed. Morphometric features of cell nuclei and AgNORs were determined by digitized computer image analysis (Prodit 5.2). The growth fraction was 5.08 for FA, 5.71 for FCD, 16.75 for DCIS and 23.26 for IC. The mean nuclear area was significantly higher in malignant cells than those of fibroadenoma and fibrocystic disease. In Ki67-positive cells the total area, long axis and number of AgNORs increased progressively across disease groups. Eccentricity of AgNORs and AgNORs: nuclear area ratios were significantly increased in malignant breast lesion in comparison with benign lesion in Ki67 positive cells. In Ki67 negative cells, the highest value of AgNORs was observed in DCIS. The AgNORs: nuclear area ratio demonstrated a statistically significant trend across the disease groups. This study demonstrates that the growth fraction, mean nuclear area and selected AgNORs features have potential for differentiating benign from malignant breast tumours.     

Cell Proliferation Indexes: a Biomarker in Solid Tumors

Clinical studies have shown that carcinogenesis is linked to the development of proliferative abnormalities. Proliferative activity has been found to have prognostic significance in a variety of human tumors. Because proliferative abnormalities can precede the occurrence of morphological abnormalities, their measurement could also serve as useful biomarkers for chemo-prevention trials. The variety of techniques for measuring cell proliferation in routine sections include mitosis counting, AgNORs, DNA precursor uptake (bromodeoxyuridine), and immunohisto-chemical detection of cell cycle proteins (PCNA, Ki-67/MIB-l). It is essential that the virtues and limitations of these methods be examined to ensure collection of meaningful clinical data.     

Analysis of human mammary fibroadenoma by Ki-67 index in the follicular and luteal phases of menstrual cycle

Objectives:  Fibroadenoma is the most common benign mammary condition among women aged 35 or younger. Expression of Ki-67 antigen has been used to compare proliferative activity of mammary fibroadenoma epithelium in the follicular and luteal phases of the menstrual cycle.
Materials and methods:  Ninety eumenorrheic women were selected for tumour excision; they were assigned to either of the two groups, according to their phase of menstrual cycle. At the end of the study, 75 patients with 87 masses were evaluated by epithelial cell Ki-67 expression, blind (no information given concerning group to which any lesion belonged).
Results:  Both groups were found to be homogeneous relative to age, menarche, body mass index, previous gestation, parity, breastfeeding, number of fibroadenomas, family history of breast cancer and tabagism. Median tumour size was 2.0 cm and no relationship between proliferative activity and nodule diameter was observed. No typical pattern was observed in the expression of Ki-67 in distinct nodules of the same patient. Average values for expression of Ki-67 (per 1000 epithelial cells) in follicular and luteal phases were 27.88 and 37.88, respectively ( P  = 0.116).
Conclusion:  Our findings revealed that proliferative activities in the mammary fibroadenoma epithelium did not present a statistically significant difference in the follicular and luteal phases. The present study contributes to clarifying that fibroadenoma is a neoplasm and does not undergo any change in the proliferative activity during the menstrual cycle.     

Prognostic significance of standardized AgNOR analysis and Ki-67 immunostaining in gastrointestinal stromal tumors

OBJECTIVE: To evaluate the prognostic utility of argyrophilic nucleolar organizer region (AgNOR) protein parameters and Ki-67-immunostained growth fraction (Ki-67 labelling index) and to correlate AgNORs with Ki-67 LI and the main clinicopathologic parameters in gastrointestinal stromal tumors (GISTs). STUDY DESIGN: On 55 patients with surgically excised GISTs, visualization and quantification of AgNORs were performed as specified in the guidelines of the Committee on AgNOR Quantification. RESULTS: AgNOR protein area (NORA) > or = 5.28 microns 2 was statistically associated with mitotic rate > or = 5 x 10 high-power fields (hpfs) (P < .001) and presence of necrosis (P < .001); Ki-67 LI > or = 9.69% was significantly associated with mitotic rate > or = 5 x 10 hpfs (P < .001), size > or = 5 cm (P = .033) and presence of necrosis (P < .001). Ki-67 LI and NORA strongly correlated. Preliminary Kaplan-Meier survival analysis showed that an increased value of NORA, Ki-67 LI, mitotic rate, tumor size and presence of necrosis had a negative influence on patient survival. Multivariate regression analysis showed that only NORA and Ki-67 LI were independent parameters in predicting the clinical outcome for patients with GISTs. Mitotic rate and necrosis remained as independent prognostic factors when NORA and Ki-67 LI were not allowed to enter in models. CONCLUSION: AgNOR protein quantity, as determined by image cytometry, and Ki-67 immunostaining seem to represent reliable predictive parameters in GISTs and are independent of mitotic rate, tumor dimension and necrosis.     

Cyclin E expression and proliferation in breast cancer.

Cyclin E is a part of the cell cycle machinery and aberrantly expressed in several malignancies including breast cancer. Since cyclin E is cell cycle specifically expressed, we wanted to examine the relation between proliferation and expression of cyclin E with special attention to tumours with overexpression of the protein. Seventy-four breast tumours were analysed for the expression of cyclin E by immunohistochemistry and Western blotting and related to the growth fraction determined by Ki-67. Significant correlations were obtained between the growth fraction, the percentage of cyclin E positive cells, the intensity of cyclin E and total amount of cyclin E determined by Western blotting. The majority of the tumours had less cyclin E than Ki-67 positive cells indicating a conserved cell cycle specific expression of the protein which further was supported by flow cytometric analysis of breast cancer cell lines. The cell cycle specificity of cyclin E was found even in tumours with inactivated retinoblastoma protein (pRB) demonstrating the existence of a pRB independent regulation of cyclin E. A fraction of the tumours had considerably elevated cyclin E levels that were not in relation to the proliferative activity as observed for the other tumours. These tumours were in general highly proliferative and considered to overexpress cyclin E. Patients with tumours of high proliferative activity, high total cyclin E levels or disproportionally elevated cyclin E expressions in relation to proliferation had significantly increased risk of death in breast cancer, whereas the intensity of the immunohistochemical cyclin E staining did not affect the survival.     

Quantitation of Ki-67 expression in the differential diagnosis of reserve cell hyperplasia vs. small cell lung carcinoma

OBJECTIVE: To investigate whether the detection of proliferation-associated Ki-67 antigen may be of value in differentiating between reserve cell hyperplasia (RCH) and small cell lung cancer (SCLC). STUDY DESIGN: Retrospectively, 20 Papanicolaou-stained bronchial brushes or washings from 20 patients were selected. Ten were diagnosed as RCH (and had no SCLC in follow-up) and the other 10 as SCLC (histologically confirmed). All 20 Papanicolaou-stained slides were restained with the monoclonal antibody MIB1, directed against Ki-67 antigen; that simple and reliable procedure was described recently. In each specimen 5 coherent cell groups were identified, corresponding to RCH or SCLC, respectively; photographed; and studied for Ki-67 antigen expression after MIB1 staining of the slides. At least 3 cell groups remained in each specimen. The Ki-67 labeling index (LI) of the specimens was determined as the number of MIB1-positive cells divided by the total number of cells in the remaining cell groups. RESULTS: All cases of SCLC showed a mean Ki-67 LI of at least .415 (mean .684, SD .151), whereas in the cases with RCH the mean Ki-67 LI never was more than .158 (mean .048, SD .049). The difference was highly significant (P<.001, Student's t test). Linear discriminant analysis resulted in a classifier with which we were able to discriminate correctly between SCLC and RCH in 100% of the 20 bronchial brushings and washings. CONCLUSION: The results clearly demonstrate that measuring proliferative activity in Papanicolaou-stained bronchial brushings and washings by MIB1 restaining of the slides may be of great practical value in accurately discriminating RCH from SCLC. The method is simple and can be performed in any laboratory that is able to carry out immunocytochemical staining. However, an additional (prospective) study with a series of difficult cases is necessary to confirm these findings.     

Expression pattern of cell cycle-related gene products in synovial stroma and synovial lining in active and quiescent stages of rheumatoid arthritis

OBJECTIVE: To investigate the expression pattern of cell cycle related gene products in active and quiescent Rheumatoid arthritis (RA). METHODS: Synovial tissue from 20 patients with active proliferative RA and 28 patients with RA in remission was immunohistochemically examined for expression of p53, p63, p21, p27, p16, cyclin D1, CDK4, RB, E2F, Ki-67 on tissue microarrays and by DNA flow cytometry for cell cycle phases. RESULTS: Elevated expression of p53 and p27 was found in synovial lining and in stromal cells in proliferative active RA. In the remission stage this finding was confined to the synovial lining. Most of the cells were in the G0-phase. Ki-67 proliferation index was maximum 10% in synovial cells. CONCLUSION: The p53 pathway is activated in synovial cells in active RA as well as in quiescent stage of disease. Differences in the spatial expression pattern of proteins involved in the p53 pathway in RA in remission compared to actively proliferating RA reflect the phasic nature of the disease and support in our opinion the concept of adaptive role of p53 pathway in RA.