Low frequency of HPV positivity in breast tumors among patients from south-central Poland

Background

Some studies suggest that Human Papilloma Virus (HPV) infection is important factor in carcinogenesis of breast tumors. This study’ objective was to analyze HPV prevalence in breast cancers of patients from south-central Poland.

Materials and methods

The study was performed based on archival paraffin embebbed and formalin fixed blocks in the group of 383 patients with breast cancer. HPV prevalence and its genotype were assessed, respectively by: nested PCR (with two groups of primers: PGMY09/PGMY11 and GP5+/GP6+), quantitative PCR (qPCR). Tumors were classified as HPV positive in case of at least one positive result in nested PCR and positive results in genotyping procedure. For all HPV positive tissues P16 immunostaining was applied in order to confirm active viral infection.

Results

In the group of 383 breast cancers, HPV positivity was found in 17 samples (4.4%) in nested PCR. All these samples were subjected to HPV genotyping. This analysis revealed presence of HPV type 16 into two tumors (0.5%). In these two cancers, P16 overexpression was reported.

Conclusion

In breast tumors of patients from south-central Poland in Poland, HPV positivity is demonstrated in very low percentage of cases.

Prognostic potential of Akt, pAkt(Ser473) and pAkt(Thr308) immunoreactivity in relation to HPV prevalence in head and neck squamous cell carcinoma patients

BACKGROUND

The prognosis of squamous cell carcinoma of head and neck (HNSCC) patients remains relatively poor over the last years. Tobacco, alcohol and active human papillomavirus (HPV) infection are involved in HNSCC development. Akt is a serine-threonine protein kinase with main phosphorylation sites at Thr308 and Ser473, which are critical to generate a high level of Akt activity.

MATERIALS AND METHODS

The aim of the study was to compare the expression and prognostic potential of total Akt and its 2 phosphorylated forms - pAkt(Ser473) and pAkt(Thr308) in relation to HPV status in HNSCC patients. The expression levels of proteins were assessed immunohistochemically. To select independent prognostic factors univariate and multivariate analyses with Cox proportional regression model were performed.

RESULTS

Among HNSCC with active HPV16 infection significantly more tumors with high Akt (67.86%, p = 0.026) and low pAkt(Ser473) (64.29%, p = 0.000) expressions were found as compared to those with HPV negativity, while there was no significant difference in the pAkt(Thr308) expression level between HPV positive and negative tumors (p = 0.359). In the whole group of HNSCC patients independent favorable prognostic factors were low T stage, low pAkt(Thr308) expression, HPV16 active infection presence (for OS and DFS) and female gender (for OS only).

CONCLUSIONS

Our results indicate an important role of pAkt(Thr308) as prognostic biomarker for HNSCC patients. There is a high probability that using Akt inhibitors would improve therapeutical benefits and treatment effectiveness, especially in HNSCC patients with high expression of pAkt.

Lack of CD44 overexpression and application of concurrent chemoradiotherapy with cisplatin independently indicate excellent prognosis in patients with HPV-positive oropharyngeal cancer

BACKGROUND

HPV-16 positivity in patients with squamous cell carcinoma of oropharynx (OPSCC) is associated with better prognosis. However, in more than 40% of HPV infected patients progression of cancer disease is observed, which indicates the presence of cancer cells resistant to therapy. Some studies suggest that there may be a subpopulation of cancer stem cells (CSCs), which simultaneously exhibit unlimited ability to self-renew and differentiate towards neoplastic cells. The relation between HPV16 infection and biomarkers of CSCs is unclear.

OBJECTIVE

The aim of the study was to compare the expression of CD44, CD98, ALDH1/2 and P16 in oropharyngeal cancer patients with or without HPV16 infection, as well as to analyze the prognostic potential of selected CSCs biomarkers in these two subgroups.

METHODS

The study was performed in a group of 63 patients. HPV16 infection status was analyzed by quantitative polymerase chain reaction, while CD44, CD98, ALDH1/2 and P16 expression by immunohistochemistry. In survival analysis, two endpoints were applied: overall survival (OS) and disease-free survival (DFS).

RESULTS

Among 63 cancers, HPV16 infection was found in 25 tumors (39.7%), overexpression of CD44, CD98, ALDH1/2 and P16 in 43 (68.2%), 30 (47.6%), 33 (52.4%) and 27 (42.9%) cancers, respectively. In the HPV16-positive subgroup, DFS rate of 100% was observed in patients with tumors characterized by lack of CD44 overexpression and those treated with concurrent chemoradiotherapy with cisplatin (CisPt-CRT). In the HPV16-negative subgroup 100% of DFS was noticed for patients (n = 6) with P16 immunopositive tumors. In this subgroup none of the CSCs biomarkers evaluated in the study had any impact on OS or DFS. In patients with HPV16-positive oropharyngeal cancer, lack of CD44 overexpression and application of CisPt-CRT were found to be positive prognostic factors.

Chemopotentiating effects of low-dose fractionated radiation on cisplatin and paclitaxel in cervix cancer cell lines and normal fibroblasts from patients with cervix cancer

The aim of the present study was to compare the effects (assessed by clonogenic survival and γH2AX foci assays) of low-dose fractionated radiation LDFR (4 × 0.125 Gy, 4 × 0.25 Gy and 4 × 0.5 Gy) versus single radiation doses (0.5 Gy, 1 Gy and 2 Gy) on cisplatin and paclitaxel in HRS-negative cervix cancer cell lines SiHa and CaSki to see if the effects of LDFR can emerge in cells that not present low-dose hyper-radiosensitivity (HRS) phenomenon. Additionally, we report the effects in normal fibroblasts (HRS-negative and HRS-positive) from two patients with cervix cancer to see if the chemopotentiating effects of LDFR also apply to normal cells. LDFR (4 × 0.125 Gy, 4 × 0.25 Gy and 4 × 0.5 Gy) as well as single doses (0.5 Gy, 1 Gy and 2 Gy) enhanced cytotoxicity of cisplatin and paclitaxel in all the cell lines. Cisplatin-potentiating effects were maximum with LDFR 4 × 0.5 Gy, and were two-fold greater than those with a single dose of 2 Gy in SiHa, CaSki and HFIB2 cells. Paclitaxel-enhancing effects were also maximum with LDFR 4 × 0.5 Gy, however only in HRS-positive HFIB2 fibroblasts were significantly greater than those with a single dose of 2 Gy. The results demonstrate that LDFR may enhance the effects of cisplatin and paclitaxel in SiHa and CaSki cells, although they lack HRS phenomenon, and show that the magnitude of the potentiating effects of LDFR depends on cytostatic type and the size of low doses. In normal fibroblasts the chemopotentiating effects of LDFR seem to depend on HRS status. In conclusion, the unique enhancing effects of LDFR on cisplatin in cervical cancer cell lines, even when HRS negative, suggest that all patients with cervical cancer may benefit from the addition of LDFR to adjuvant cisplatin-based chemotherapy.

Determination of cytogenetic markers for biological monitoring in coypu (Myocastor coypu)

Cytogenetic tests are used to assess the influence of physical and chemical factors with potential mutagenic and genotoxic properties on the animal organism. The test results make it possible to eliminate mutagens, as well as helping predict possible genetic consequences in animal cells and assess animal resistance. The aim of this study was to examine, using cytogenetic tests, the spontaneous chromosome and DNA damage in coypu lymphocytes. Four tests: fragile site (FS), bleomycin (BLM), micronucleus, (MN) and comet were used for the first time in coypu cells. The averages with standard deviations obtained in the research were as follows: 3.30 ± 0.80 fragile sites/cell; 0.63 ± 0.80 BLM damage/cell; 6.10 ± 0.53% binucleated cells with MN; and 3.24 ± 0.63% DNA in tail. The present analysis showed high interindividual variation in spontaneous chromosomal and DNA damage levels. In the case of micronucleus, fragile sites, and comet assays, the differences between animals were statistically significant. The data suggest that these assays are sensitive enough to detect some effects on an individual animal and can be proposed as tools for coypu biomonitoring.

Active HPV infection and its influence on survival in head and neck squamous-cell cancer

Purpose

HPV is involved in the development of some head and neck squamous-cell carcinomas (HNSCC). It was suggested that only transcriptionally active virus can induce carcinogenesis, therefore, the aim of our study was to analyze the frequency of active HPV infection, virus type, and its prognostic role in HNSCC patients.

Methods

Status of active HPV infection was assessed for 155 HNSCC patients based on p16 expression and HPV DNA presence. Univariate and multivariate analyses with Cox proportional regression model were performed to select independent prognostic factors.

Results

Active HPV infection was detected in 20.65% of patients. We identified 16.0, 40.9 and 1.7% of HPV positive oral cavity, oropharyngeal, and laryngeal cancer cases, respectively. HPV16 was dominant (81.25%) followed by HPV35 (9.38%) and double infections with HPV16 and 35 (6.25%) or HPV35 and 18 (3.12%). Patients with active HPV infection demonstrated significantly higher survival than HPV negative ones (OS 80.89% vs. 37.08%, p = 0.000; DFS 93.0% vs. 53.35%, p = 0.000, respectively). Longer OS and DFS were maintained for infected patients when oropharyngeal and non-oropharyngeal cases were analyzed separately. Interestingly, all patients infected with other than HPV16 types survived 5 years without cancer progression. In the analyzed group of 155 patients the strongest independent favourable prognostic factor for both OS and DFS was HPV presence.

Conclusions

High prevalence of HPV-driven HNSCC (mostly within oropharynx) was detected, with HPV16 type the most frequent, followed by HPV35 and HPV18. The presence of active HPV infection improved survival of both oropharyngeal and non-oropharyngeal cancer patients and should be taken into account in treatment planning.

The prevalence of HPV infection in rectal cancer - Report from South - Central Poland (Cracow region)

Some studies suggest that HPV infection may be important carcinogenic factor in development of some part of colorectal cancers. However, in the worldwide literature concerning this type of tumours, the great variability in HPV frequency is noticed. In Poland, the incidence of HPV infection in colorectal cancers was examined in five studies so far and their results are also conflicting. Therefore, the aim of the present study was to assess the HPV presence in the group of 120 patients with adenocarcinomas of rectum. HPV infection was assessed on the basis of DNA extracted from collected formalin fixed paraffin embedded tumour specimens. Viral presence was evaluated using two PCR based methods: nested PCR and quantitative PCR (qPCR) with primers specific for HPV16. All HPV positive samples were subjected to virus genotyping using AmoyDx^® Human papillomavirus (HPV) Genotyping Detection Kit and P16 immunostaining. Among 120 evaluated colorectal tumours, HPV DNA was detected in 2 cancers (1.67%) by nested PCR and in 2 (1.67%) tumours by qPCR, including 1 sample diagnosed as HPV positive on the basis of both PCR variants. Two HPV positive cancers had HPV16 infection and other one HPV18. All three tumours with positivity of HPV DNA were P16 negative. In south - central Poland, HPV infection in rectal cancers probably has not influence on rectal carcinogenesis.

Low-Dose Hypersensitive Response for Residual pATM and γH2AX Foci in Normal Fibroblasts of Cancer Patients

PURPOSE

To define the dose-response relationship for initial and residual pATM and γH2AX foci and temporal response of pATM foci in fibroblasts of 4 hyper-radiosensitivity (HRS)-positive cancer patients and 8 HRS-negative cancer patients and answer the question regarding the role of DNA double-strand break (DSB) recognition and repair in the mechanism of HRS.

METHODS AND MATERIALS

The cells were irradiated with single doses (0.1-4 Gy) of 6-MV X rays. The number of initial and residual pATM and γH2AX foci was assessed 1 hour and 24 hours after irradiation, respectively. Kinetics of DSB recognition and repair was estimated by pATM foci assay after irradiation with 0.2 and 2 Gy.

RESULTS

Hyper-radiosensitivity response (confirmed by the induced-repair model) was clearly evident for residual pATM and γH2AX foci in fibroblasts of HRS-positive patients but not in fibroblasts of HRS-negative patients. Significantly less DSB was recognized by pATM early (10-30 minutes) after irradiation with 0.2 Gy in HRS-positive compared with HRS-negative fibroblasts.

CONCLUSIONS

The present results provide evidence for the role of DSB recognition by pATM and repair in the mechanism of HRS and seem to support the idea of nucleo-shuttling of the pATM protein to be involved in HRS response.

Differences in the prognosis of HPV16-positive patients with squamous cell carcinoma of head and neck according to viral load and expression of P16

Purpose

To evaluate the impact of HPV16 load (VL—the number of virus genome copies per cell) and P16 expression on prognosis of patients with squamous cell carcinomas (SCCs) of head and neck (HN).

Materials and methods

HPV16 presence was assessed in the group of 109 patients with HNSCCs by quantitative polymerase chain reaction (qPCR). VL (assessed by qPCR) and P16 expression (evaluated by immunohistochemistry) were analysed only in the subgroup of HPV16-positive tumours. These features were correlated with 5-year overall survival (OS) and disease-free survival (DFS).

Results

HPV16 infection was found in 36 tumours (33.0%). Virus-positive patients had better OS and DFS than those without infection (P = 0.041 and 0.005). Among HPV16-positive HNSCCs, 18 (50.0%) had higher VL (median value > 6764.3 copies/cell) and 25 (73.5%) P16 over expression. The significant differences in OS and DFS (P = 0.008 and 0.004) were noticed according to VL, wherein 100% DFS was found for patients with higher VL. According to P16 expression, significant difference was found only for OS (P = 0.020). In multivariate analysis, VL (P = 0.045; HR = 2.795; CI 0.121–1.060) and the level of smoking (P = 0.023, HR = 2.253; CI 1.124–4.514) were independent factors affecting DFS of HPV16-positive patients.

Conclusion

On the basis of viral load, it is possible to differentiate prognosis of patients with HPV16-positive HNSCCs. In this subgroup, viral load has stronger prognostic potential than P16 expression.

The search for optimal cutoff points for apoptosis and proliferation rate in prognostification of early stage breast cancer patients treated with anthracyclines in adjuvant settings

Cancer growth is determined by the proportion of proliferating to dying cells; thus, the aim of the study was to analyze how proliferation rate and apoptosis level affect disease-free survival (DFS) of breast cancer (BC) patients treated with anthracycline-based chemotherapy. For 172 BC, proliferation rate was investigated by Ki-67 labeling index (Ki-67 LI)-assessed immunohistochemically. Apoptosis level was analyzed by apoptotic index (AI) estimated by terminal deoxynucleotidyl transferase dUTP nick end labeling assay. To stratify patients into subgroups with higher and lower DFS and to achieve optimal categorization, optimal cutoff points were searching by minimal P value method. The best separation of DFS curves (P = 0.001) was observed for three categories of AI: (i) AI >1.8 % (DFS = 100 %), (ii) AI ≤0.3 % (DFS = 84.6 %), and (iii) 1.8 % <= AI >0.3 % (DFS = 64.0 %). The highest DFS (86.1 %) was shown for the subgroup with low-proliferating BC (Ki-67 LI ≤18.0 %), intermediate (73.9 %) for patients characterized by Ki-67 LI in the range 18.0-37.0 % and the lowest (60.0 %) for women with fast-proliferating tumors (Ki-67 LI >37.0 %) (P = 0.022). Summarized, minimal P value method allows for optimal separation of survival curves. Apoptosis level and proliferation rate have some prognostic potential for early stage breast cancer patients treated with anthracyclines in adjuvant setting, however, as suggested by multivariate analysis, not as independent prognostic factors.

An association between low-dose hyper-radiosensitivity and the early G2-phase checkpoint in normal fibroblasts of cancer patients

In our previous study, low-dose hyper-radiosensitivity (HRS) effect was demonstrated for normal fibroblasts (asynchronous and G2-phase enriched) of 4 of the 25 cancer patients investigated. For the rest of patients, HRS was not defined in either of the 2 fibroblast populations. Thus, the study indicated that G2-phase enrichment had no influence on HRS identification. The conclusion contradicts that reported for human tumor cells, and suggests different mechanism of HRS in normal human cells. In the present paper we report, for the first time, the activity of early G2-phase checkpoint after low-dose irradiation in normal fibroblasts of these 4 HRS-positive patients and 4 HRS-negative patients and answer the question regarding the role of this checkpoint in normal human cells. The response of the early G2-phase checkpoint was determined by assessment of the progression of irradiated cells into mitosis using the mitotic marker, phosphorylated histone H3. We found evident differences in the activity of the early G2-phase checkpoint between HRS-positive and HRS-negative fibroblasts. In HRS-positive fibroblasts the checkpoint was not triggered and DNA damage was not recognized after doses lower than 0.2Gy resulting in HRS response. On the contrary, in HRS-negative fibroblasts the early G2-phase checkpoint was activated regardless of the dose in the range 0.1-2Gy. In conclusion, although cell cycle phase has no effect on the presence of HRS effect in normal human fibroblasts, the data reported here indicate that HRS response in these cells is associated with the functioning of early G2-phase checkpoint in a threshold-dose dependent manner, similarly as it takes place in most of human tumor and other cells.

Relative biological effectiveness of the 60-MeV therapeutic proton beam at the Institute of Nuclear Physics (IFJ PAN) in Kraków, Poland

The aim of the study was to determine the relative biological effectiveness (RBE) of a 60-MeV proton radiotherapy beam at the Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN) in Kraków, the first one to operate in Poland. RBE was assessed at the surviving fractions (SFs) of 0.01, 0.1, and 0.37, for normal human fibroblasts from three cancer patients. The cells were irradiated near the Bragg peak of the pristine beam and at three depths within a 28.4-mm spread-out Bragg peak (SOBP). Reference radiation was provided by 6-MV X-rays. The mean RBE value at SF = 0.01 for fibroblasts irradiated near the Bragg peak of pristine beam ranged between 1.06 and 1.15. The mean RBE values at SF = 0.01 for these cells exposed at depths of 2, 15, and 27 mm of the SOBP ranged between 0.95-1.00, 0.97-1.02, and 1.05-1.11, respectively. A trend was observed for RBE values to increase with survival level and with depth in the SOBP: at SF = 0.37 and at the depth of 27 mm, RBE values attained their maximum (1.19-1.24). The RBE values estimated at SF = 0.01 using normal human fibroblasts for the 60-MeV proton radiotherapy beam at the IFJ PAN in Kraków are close to values of 1.0 and 1.1, used in clinical practice.

Low-Dose Radiation Response of Primary Keratinocytes and Fibroblasts from Patients with Cervix Cancer

The aim of the present study was to examine, using the micronucleus (MN) assay, the low-dose radiation response of normal skin cells from cancer patients and to determine whether the hyper-radiosensitivity (HRS)-like phenomenon occurs in cells of these patients. Primary skin fibroblasts and keratinocytes derived from 40 patients with cervix cancer were studied. After in vitro gamma irradiation with single doses ranging from 0.05 to 4 Gy, MN induction was assessed. For each patient, the linear-quadratic (LQ) model and the induced repair (IR) model were fitted over the whole data set. In fits of the IR model, an HRS-like response after low doses (seen as the deviation over the LQ curve) was demonstrated for the fibroblasts of two patients and for the keratinocytes of four other patients. The alpha(s)/alpha(r) ratio for the six patients ranged from 2.7 to 15.4, whereas the values of the parameter d(c) ranged from 0.13 to 0.36 Gy. No relationship was observed between chromosomal radiosensitivity of fibroblasts and keratinocytes derived from the same donor in the low-dose (0.1-0.25 Gy) region. In conclusion, the fact that low-dose chromosomal hypersensitivity was observed for cells of only six of the patients studied suggests that it is not a common finding in human normal cells and can represent an individual characteristic.

Evidence of low-dose hyper-radiosensitivity in normal cells of cervix cancer patients?

The aim of the present study was to examine the low-dose radiation response of human normal cells using the micronucleus assay. Skin fibroblasts and keratinocytes derived from 40 cervix cancer patients were studied. After in vitro gamma irradiation with single doses ranging from 0.05 to 4 Gy, the fraction of binucleated cells with micronuclei was assessed. For each patient, the Linear-Quadratic (LQ) model and the Induced-Repair (IR) model were fitted over the whole data set (0.05-4 Gy). In conclusion, the present study showed some evidence of low-dose hypersensitivity in the fibroblasts of two patients and in the keratinocytes of four of the forty patients studied.

Clonogenic survival of human keratinocytes and rodent fibroblasts after irradiation with 25 kV x-rays

Low energy x-rays (E(ph) </=50 keV) are widely used in diagnostic radiology and radiotherapy. However, data on their relative biological effectiveness (RBE) are scarce. Of particular importance for risk estimation are the RBE values of x-rays in the range which is commonly used in mammography (10-30 keV). We have determined clonogenic survival after low-energy x-ray irradiation for three cell lines: primary human epidermal keratinocytes (HEKn), mouse fibroblasts (NIH/3T3) and Chinese hamster fibroblasts (V79). Experiments were performed with a 25 kV x-ray tube and compared to 200 kV x-rays as a reference. Compared to the effect of 200 kV x-rays, irradiation with 25 kV x-rays resulted in a decreased survival rate in the murine fibroblasts, but not in the human epithelial cell line. The RBE value was calculated for 10% surviving fraction. For HEKn cells, RBE was 1.33+/-0.27, for NIH/3T3 cells 1.25+/-0.07 and for V79 cells 1.10+/-0.09, respectively. No consistently increased RBE was observed in the various cell lines. Nevertheless, a potential of increased cytogenetic changes has to be considered for risk estimation of low-energy x-rays.

Induction of micronuclei in human fibroblasts and keratinocytes by 25 kV x-rays

A relative biological effectiveness (RBE) not much larger than unity is usually assumed for soft x-rays (up to approximately 50 keV) that are applied in diagnostic radiology such as mammography, in conventional radiotherapy and in novel radiotherapy approaches such as x-ray phototherapy. On the other hand, there have been recent claims of an RBE of more than 3 for mammography and respective conventional x-rays. Detailed data on the RBE of soft x-rays, however, are scarce. The aim of the present study was to determine the effect of low-energy x-rays on chromosomal damage in vitro, in terms of micronucleus induction. Experiments were performed with 25 kV x-rays and a 200 kV x-ray reference source. The studies were carried out on primary human epidermal keratinocytes (HEKn), human fibroblasts (HFIB) and NIH/3T3 mouse fibroblasts. Micronucleus (MN) induction was assayed after in vitro irradiation with doses ranging from 1 to 5.2 Gy. Compared to the effect of 200 kV x-rays, 25 kV x-rays resulted in moderately increased chromosomal damage in all cell lines studied. This increase was observed for the percentage of binucleated (BN) cells with micronuclei as well as for the number of micronuclei per BN cell. Moreover, the increased number of micronuclei per micronucleated BN cell in human keratinocytes and 3T3 mouse fibroblasts suggests that soft x-rays induce a different quality of damage. For all cell lines studied the analysis of micronucleus induction by 25 kV soft x-rays compared to 200 kV x-rays resulted in an RBE value of about 1.3. This indicates a somewhat enhanced potential of soft x-rays for induction of genetic effects.

Intrinsic radiosensitivity of healthy donors and cancer patients as determined by the lymphocyte micronucleus assay

The purpose of the study was to evaluate the usefulness of the cytokinesis-block micronucleus (MN) assay in assessment of radiosensitivity of lymphocytes in cancer patients. Lymphocytes from 15 cervical cancer patients, 21 head and neck cancer patients, seven lung cancer patients and 19 healthy donors were analysed using MN assay. The proportion of binucleate cells (BC) in cancer patients ranged from 22 to 56% and was significantly lower than in the control group (38-68%). MN frequency assessed five times over 6 months in four healthy donors showed that the interindividual variation was significantly higher than intraindividual. Before (0 Gy) and after irradiation (2 and 4 Gy) no statistical differences in the mean number of MN/BC were observed between healthy donors and cancer patient groups. Nevertheless, statistical cluster analysis allowed each group of donors to be divided into radioresistant and radiosensitive subgroups of patients. They showed significantly different dose response. Separate comparison of the mean MN frequency within all examined radioresistant and radiosensitive subgroups, showed statistically significant differences only after a dose of 4 Gy. At this dose, the lung cancer patients and cervical cancer patients from radiosensitive subgroups presented significantly higher radiosensitivity than the healthy donors. However, healthy donors from radioresistant subgroup did not differ significantly from cancer patients. This work has shown a high variation in interindividual radiosensitivity of donors and suggests the possibility of identifying radiosensitive patients on the basis of MN assay performed on lymphocytes.

Measurement of DNA ploidy and proliferation rate in lung tumours by bromodeoxyuridine labelling index, S-phase fraction and AgNOR technique

Proliferative rate and DNA ploidy in 23 squamous cell carcinoma of the lung (SCCL), 10 adenocarcinomas (ACL) and 4 metastatic tumours (MT) were studied. The proliferative potential of the tumours was assessed with the use of three methods: bromodeoxyuridine labelling index (BrdUrd LI), S-phase fraction (SPF) and argyrophilic organizer regions (AgNOR) technique. Differences in the proliferating rate between different histological groups of tumours and within groups were shown by the BrdUrdLI and AgNOR technique. However, for the BrdUrdLI only these differences were statistically significant. No correlation was found between the values for all examined tests and the clinical stage of the tumours. The broadest range of the BrdUrdLI values was for SCCL and the mean BrdUrdLI was highest in this histological group. The number of SPF cells in metastatic tumours was lower than that in two other histological groups, however it was not a significant difference. The highest number of AgNORs and tot AgNOR area per cell was noticed again in SCCL, however, these values were not significantly different (p = 0.189) from other histological groups. Also the mean size of AgNOR particle area did not differ between groups (p = 0.279). Twenty six of thirty seven (70%) tumours were aneuploid. The highest percentage was recorded for SCCL (81%), while the lowest (25%) for MT. In the aneuploid tumours no significantly higher proliferation rate was observed as assessed by the BrdUrdLI and SPF. However, higher AgNOR numbers (p = 0.0472) and higher tot AgNOR area per cell (p = 0.0128) in aneuploid than in diploid tumours were observed. There was no correlation between BrdUrdLI, SPF and AgNOR counts.