Apoptosis in gastric carcinomas and its association with cell proliferation and differentiation

Expression and significances of apoptosis gene, invasion-associated proteases and vascular epithelial growth factor in Lauren's classification of gastric carcinoma

AIM: To explore distinctive biological behavior in the intestinal-type gastric carcinoma and diffuse-type gastric carcinoma, according to the expression of Bcl-2, Bax, Cath-D and vascular epithelial growth factor (VEGF).

METHODS: Immunohistochemistry SP method was performed to detect the expression of Bcl-2, Bax, Cath-D and VEGF in 36 cases of intestinal-type gastric carcinoma, 38 cases of diffuse-type gastric carcinoma, and their corresponding normal gastric tissues.

RESULTS: The expression of Bcl-2, Bax, Cath-D and VEGF were significantly higher in gastric carcinoma than those in the normal controls (44.59% vs 27.30%; 58.11% vs 71.62%; 77.00% vs 21.60%; 71.62% vs 14.86%; all P < 0.05). The positive expression of Bcl-2 and Cath-D were markedly higher in diffuse-type gastric carcinoma than those in intestinal-type one (29.14 ± 24.70 vs 19.80 ± 27.37; 52.59 ± 33.76 vs 29.21 ± 39.67; both P < 0.05), while the expression of Bax was notably lower in the former (32.56 ± 35.55 vs 47.74 ± 27.43, P < 0.05). The positive rate of VEGF expression was closely correlated with the invasion depth (7.13 ± 15.81, 62.77 ± 44.37, and 40.82 ± 42.70 for mucosal or sub-mucosal invasion, muscular invasion, and serosa invasion, respectively) and lymph node metastasis (metastasis vs non-metastasis: 42.05 ± 42.61 vs 34.15 ± 42.52) of gastric carcinoma.

CONCLUSION: Bcl-2, Bax, Cath-D and VEGF are involved in the development and metastasis of gastric cancer. Due to the involvement of different genes, the intestinal-type or diffuse-type gastric carcinoma shows a distinctive biological behavior.

Long-term evaluation of mice model infected with Helicobacter pylori: focus on gastric pathology including gastric cancer

BACKGROUND

Long-term evaluation of gastric pathology after H. pylori infection is very important in order to reveal its clinical implications, since debate still exists on the gastric carcinogenesis provoked by H. pylori infection in animal models.

AIM

Either to evaluate the long-term outcome of H. pylori infection or to determine how H. pylori could provoke gastric cancer in the mice model.

METHODS

Four-week-old specific pathogen free C57BL/6 mice (n = 115) were infected with SS1, the mouse-adapted H. pylori strain. After 4, 8, 16, 24, 36, 50 and 80 weeks of bacterial infection, the H. pylori-infected mice were sacrificed.

RESULTS

After 80 weeks of infection, almost all the H. pylori-infected mice developed hyperplastic gastritis, but did not show any evidence of gastric adenoma, dysplasia or carcinoma. PCNA positive cells were most abundant after 50 weeks and tended to decrease thereafter up to 80 weeks, whereas apoptosis began to be noted 8 weeks after H. pylori infection, showing 7-8 apoptotic cells/high power field, and tending to increase as time passed. Normally observed neutral mucin decreased during the experiment, showing the most marked decrease 50 weeks after H. pylori infection. In contrast, acidic mucin was noted from 50 weeks after infection.

CONCLUSION

The SS1-infected mouse seems to be a suitable animal model for H. pylori-related research, and H. pylori itself does not induce gastric cancer in normal wild-type mouse model following long-term exposure, which could be explained by the balance that exists between cell proliferation and apoptosis.

Survivin expression in tumor cell nuclei is predictive of a favorable prognosis in gastric cancer patients

One hundred and thirty three gastric cancer cases were investigated immunohistochemically to clarify the biological role of survivin in gastric cancer cells using a commercially available anti-survivin antibody (SURV11A). Five gastric cancer cell lines were employed to assess localization of survivin by reverse-transcription-polymerase chain reaction (RT-PCR) Southern blotting, Western blotting and immunofluorescence, signals being found in both nucleus and cytoplasm. Survivin nuclear staining of gastric cancer cells was evident in 109 of 133 cases (82.0%) and associated with a favorable prognosis, being an independent prognosticator on multivariate analysis. Survivin nuclear positivity also correlated with younger age and lower incidence of vessel cancer invasion. In contrast, survivin cytoplasmic positivity was noted in 117 cases (88.0%) and did not correlate with any factor of progression or prognosis. The results indicate that survivin is present in the majority of gastric cancer cells but a nuclear localization may play an important physiological role in hindering tumor progression.

Pretreatment apoptotic scores do not predict response to radiation therapy in oropharyngeal squamous cell carcinoma

The prognostic value of tumor apoptosis was studied in patients with oropharyngeal squamous cell carcinoma treated with radical radiotherapy. Forty-eight patients with oropharyngeal squamous cell carcinoma who received radical radiotherapy between 1990 and 1995 were enrolled in the study. The radiation treatment for all patients involved the administration of 65 Gy in 26 fractions over a 6.5-week period. The apoptotic index (AI; the apoptotic cell count per 1000 tumor cells ) was distributed from 0 to 10 with a median at 2 and a mode of 1. There was a significant linear correlation between the AI and mitotic index (MI) (r=0.393, 95% confidence interval: 0.129-0.605). The cause-specific 5-year survival for patients with AI greater than the median was 46% and for the counterpart was 41%. There was no difference in cause-specific survival between AI/MI greater than the median (50%) and AI/MI smaller than the median (36%). The number of patients was too small to draw definite conclusions, but the AI and the AI/MI before treatment were not shown to have a prognostic value for oropharyngeal squamous cell carcinoma in our study. The primary sites and treatment methods may influence the prognostic value of AI even for the same histological types.

Induction of apoptosis by arsenic trioxide and hydroxy camptothecin in gastriccancer cells in vitro

AIM:To study the effects of arsenic trioxide and HCPT on dif ferent degrees of differentiated gastric cancer cells (SGC-7901, MKN-45, MKN-28) with respect to both cytotoxicity and induction of apoptosis in vitro.METHODS:The cytotoxicity of As(2)O(3) and HCPT on gastric cancer cells was det ermined by MTT assay.Morphologic changes of apoptosis of gastric cancer cells were observed by light microscopy and transmission electron microscopy.Apoptosis and cell cycle changes of gastric cancer cells induced by HCPT and As(2)O(3) we re investigated by TUNEL method and flow cytometry.RESULTS:As(2)O(3) and HCPT had remarkable cytotoxic effects on different degrees of differentiated gastric cancer cells. The IC(50) of As(2)O(3) on well differentiated gastric cancer cell MKN-28, moderately differentiated gastric cancer cell SGC-7901, and poorly differentiated gastric cancer cell MKN-28 were 8.91 &mgr;mol/L, 10.57 &mgr;mol/L, and 11.65&mgr;mol/L, respectively. The IC(50) of HCP T on MKN-28, SGC-7901, and MKN-45 were 9.35 mg/L, 10.21 mg/L,and 12.63 mg/L respectively after 48 h treatment. After 12 h of exposure to both drugs, gastric cancer cells exhibited morphologic features of apoptosis, includ ing cell shrinkage,nuclear condensation, and formation of apoptotic bodies. A ty pical subdiploid peak before G(0)/G(1) phase was observed by flow cytometry. The apoptotic rates of SGC-7901, MKN-45, and MKN-28 were 13.84%, 22.52%, and 9.68%, respectively after48 h exposure to 10&mgr;mol/L As(2)O(3). The apoptotic ra tes of SGC-7901, MKN-45, and MKN-28 were 21.88%, 12.35%, and 30.26%, resp ectively after 48 h exposure to 10 mg/L HCPT. The apoptotic indice were 7%-15% a s assessed by TUNEL method. The effect of As(2)O(3) on SGC-7901 showed remarkab le cell cycle specificity, which induced cell death in G(1) phase, and blocked G(2)/M phase.HCPT also showed a remarkable cell cycle specificity, by inducing cell death and apoptosis in G(1) phase and arrest of proliferation at Sphase.CONCLUSION:As(2)O(3) and HCPT exhibit significant cytotoxicity on gastric canc er cells by induction of apoptosis. As(2)O(3) and HCPT might have a promising pr ospect in the treatment of gastric cancer, which needs to be further studied.

Apoptosis and p53 in inverting papilloma of the sinonasal tract

The objective of this study was to identify apoptotic bodies and p53 positivity in inverting papilloma lesions to study these two as biomarkers in premalignant lesions. Archival specimens of 15 patients with inverting papilloma between the years 1992 and 1995 were retrieved. In situ end labeling technique was used to identify apoptotic bodies. Immunohistochemistry was used to detect p53 in the same specimens. The clinical course was evaluated conducting a retrospective chart review in these patients. Compared to normal epithelium, inverting papilloma lesions had a greater proportion of apoptotic bodies, which was nearly statistically significant (average 0.506/100 cells for inverting papilloma compared with 0.1/100 cells for the normal surrounding tissue). Four cases of inverting papilloma were p53 positive. There was, however, no association between p53 positive staining and the apoptotic rate. The minimum follow-up for patients was 2 years. All had a uniformly good clinical outcome with only one patient who was p53 positive showing concurrent squamous cell carcinoma. We concluded that inverting papilloma contained a higher average number of apoptotic bodies compared with normal surrounding sinonasal tissue. This showed a trend toward a positive between the apoptotic rate and premalignancy, suggesting both increased cellular proliferation and increased cell death may occur in such lesions. In this study p53 did not show a positive association with the apoptotic rate, suggesting that p53 may not be directly involved in the apoptotic regulatory pathway in inverting papillomas.

Tumor proliferation and apoptosis in human uterine cervix carcinoma I: correlations between variables

PURPOSE

Parameters for tumor proliferation and apoptosis were studied prospectively in 84 previously untreated patients with a diagnosis of carcinoma of the uterine cervix.

MATERIALS AND METHODS

Tumor proliferation was assessed by in vivo labeling with bromodeoxyuridine (BrdU), followed by a biopsy of the tumor 4-10 h thereafter during an examination under anesthesia. The potential doubling time (Tpot) was obtained by deriving the BrdU labeling index (LI) and S-phase duration (Ts) using flow cytometry. The LI for BrdU and its staining pattern were also determined immunohistochemically. Apoptosis was assessed histologically using morphological criteria.

RESULTS

Seven patients were excluded and the FIGO stages of the remaining 77 patients were as follows: IB and IIA, 20 patients; IIB, 29 patients; IIIB and IV, 28 patients. The median tumor diameter was 6 cm. There were 61 squamous cell, 11 adeno- and five adenosquamous carcinomas. Of the 63 patients in whom the tumor grade could be determined, 37 were well or moderately well differentiated and the remaining 26 were poorly differentiated. The median mitotic index (MI) was 0.7%. There were 43 diploid and 34 aneuploid tumors. Median values for Ts and S-phase fraction (SPF) were 9.9 h and 16%, respectively. The median BrdU LI by flow cytometry (LI-fc) was 6.7%. There was a significant correlation between LI-fc and LI by histology, although values for the latter (median 11.1%) were consistently higher than those determined by flow cytometry by a factor of 1.5. The median Tpot value was 5.0 days. The median apoptotic index (AI) was 1.0% and AI correlated positively with LI-fc. Median values for LI-fc increased with increasing tumor size and were 5.1%, 6.4%, 7.5% and 11.0% for tumors measuring < or = 4 cm, 4-6 cm, 6-8 cm and > 8 cm, respectively. The remaining proliferation parameters, however, showed no correlation with tumor size, stage, grade or histologic type.

CONCLUSIONS

In carcinomas of the cervix, tumor proliferation is positively associated with apoptosis and tumor size. These findings suggest that parameters for tumor proliferation and apoptosis are associated with tumor progression and may thus be predictive of clinical outcome.

MVAC chemotherapy-induced apoptosis and p53 alterations in the rat model of bladder cancer

OBJECTIVES

To investigate the induction of apoptosis by methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) therapy as well as p53 alterations in a rat model of bladder cancer induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN).

METHODS

At 20 and 28 weeks after starting the administration of BBN, 60 rats (30 at 20 weeks, and 30 at 28 weeks) were divided into an MVAC treatment group (20 rats) and a control group of untreated rats (10 rats). After one intraperitoneal injection of MVAC, the rat bladder was obtained on day 1 or 7 for evaluation of apoptosis by biohistochemical and electron microscopic observations, and of p53 alterations immunohistochemically.

RESULTS

All tumors were noninvasive transitional cell carcinoma (TCC) at 20 weeks and invasive TCC at 28 weeks. In comparison with untreated tumors, a threefold increase of apoptotic indexes (Als) was noted in invasive TCC and a twofold increase in noninvasive TCC on day 1 after MVAC therapy. Both decreased Als and a frequent occurrence of apoptotic necrosis were observed on day 7. Occurrence of tumor necrosis was not affected by MVAC therapy, and the extent of necrosis was not related to apoptosis. Detection of p53 alterations, 45% and 40% in MVAC treated and untreated tumors, respectively, did not correlate with Als.

CONCLUSIONS

MVAC therapy may act through the induction of apoptosis, and invasive TCC cells may be much more sensitive to MVAC therapy in the rat model of bladder cancer. Neither spontaneous nor MVAC-induced apoptosis may be related to p53 alterations in the rat model of bladder cancer.

Progesterone therapy for endometrial carcinoma reduces cell proliferation but does not alter apoptosis

BACKGROUND

Although the anticancer effects of progesterone therapy for patients with endometrial carcinoma are widely acknowledged, a detailed assessment of the resultant morphologic alterations in tumor tissue kinetics has hitherto been lacking.

METHODS

Biopsy and hysterectomy specimens of 14 endometrial carcinomas (endometrioid-type) before and during progesterone therapy were studied to clarify changes in apoptosis and cell proliferation and their relation to morphologic alterations. The extent of squamous differentiation within tumor lesions was also examined.

RESULTS

In the good-response group, tumor cells took on characteristics of normal endometrial gland cells in the secretory phase. A positive correlation between reduction in the mitotic index and the degree of morphologic alterations during hormone therapy was observed, but the frequency of apoptotic cells did not vary. In both the good-response and poor-response groups, development or enlargement of squamous areas was observed, in comparison with the initial biopsy specimens.

CONCLUSIONS

These results suggest that prolonged progesterone administration can suppress cell proliferation in endometrial carcinomas through tumor cell differentiation without altering apoptosis, resulting in a shift in tissue kinetics toward a relative predominance of cell deletion. In addition, increases in the occurrence of squamous areas within tumors do not always appear to be related to treatment efficacy.

Detection of DNA Fragmentation in Human Breast Cancer Tissue by an Antibody Specific to Single-stranded DNA

While there have been many reports concerning the clinical significance of bcl-2 expression in human breast cancer, little is known about apoptosis in primary breast cancers. We immunohistochemically examined DNA fragmentation in 107 primary human breast cancers from Japanese women using an antibody specific to single-stranded DNA. The apoptosis index calculated as the product of the positive cell number and the cellularity coefficient, ranged from 0 to 48. The average incidence of apoptosis was calculated as 0.1% of tumor cells. No relationships were observed among the apoptosis index, expression of bcl-2, and the histological grade of the tumors. Almost all apoptotic cells were phagocytosed by surrounding tumor cells immediately after DNA fragmentation. Apoptotic body formation was rare. The apoptotic cells seemed to be degraded within phagocytes, leaving no trace of apoptosis except the tiny shells of nuclei. The intensive phagocytic reaction might be one of the main reasons for the low incidence of apoptosis in human breast cancers.

Low levels of apoptosis and proliferative activity in colorectal villous tumors: comparison with tubular tumors

In order to clarify the cell kinetics of colorectal villous tumors (VT), 21 villous adenomatous areas and 12 carcinomatous areas within villous adenomas were investigated for proliferative activity and apoptosis and compared with a series of 41 tubular tumors (TT), demonstrating elements of intramucosal carcinomas as well as tubular adenomas (so-called carcinoma in tubular adenoma). Proliferation was estimated in terms of Ki-67 labeling indices and mitotic indices, and apoptosis was assessed by DNA nick-end labeling to give apoptotic indices. Apoptotic indices of villous adenomatous and carcinomatous regions were significantly lower than the values for their tubular counterparts. Ki-67 labeling indices were also significantly lower for adenoma components. Apoptotic indices, Ki-67 labeling indices and mitotic indices increased with atypia raised in tubular adenoma components. Correlations of mitotic indices with apoptotic indices, Ki-67 labeling indices with apoptotic indices and mitotic indices with Ki-67 labeling indices were found for each villous tumor group and tubular tumor group, and the apoptosis and proliferation ratios for villous tumors were relatively low, suggesting a tendency for greater growth due to less cell deletion. Although this is only one of the biological features of villous tumor groups, it might play a major role in generation of malignancy.

Apoptosis and carcinogenesis: morphologic observations in the rat bladder treated with N-butyl-N-(4-hydroxybutyl)nitrosamine

BACKGROUND

We investigated the role of apoptosis in rat bladder carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN).

METHODS

Apoptosis was detected in BBN-induced rat bladder lesions by routine hematoxylin and eosin (H&E) staining, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL), and transmission electron microscopic examinations.

RESULTS

After administration of BBN, various pathologic changes were observed in the rat bladder after intervals of between 4 and 28 weeks. Through a comparative study in serial sections, the incidence of apoptosis, detected by either routine H&E staining or TUNEL staining, displayed marked elevation in BBN-induced rat bladder lesions, as compared to that in the normal epithelium of the rat bladder, particularly in invasive transitional cell carcinoma. Apoptotic cells with different morphologic features were ultrastructurally demonstrated in a series of rat bladder lesions. Significant group differences in the incidence of apoptosis were seen among the BBN-induced lesions and the normal epithelium of the rat bladder, and among the invasive transitional cell carcinomas and other lesions, before the tumor cells were seen to invade the rat bladder.

CONCLUSION

Our data suggest that apoptosis may be closely related to carcinogenesis and tumor invasion of the rat bladder induced by BBN, and that the comparative study of serial sections, each stained by H&E and TUNEL, combined with electron microscopic observation, may provide the most reliable informations in semiquantitative assessment of apoptosis.

[Significance of apoptotic processes in radiotherapy. II]

Apoptosis is known as an active process of cell death forced by radio- and chemotherapy. Therefore, established concepts (terms, therapy schemes) will reflect a picture different from that usually seen, when examined under the apoptotic point of view. Furthermore, the development of new concepts for innovative diagnosis, prognosis and therapy could be accomplished. This is an attempt to reveal actual features of both aspects.

Incidence of apoptosis and metallothionein expression in renal cell carcinoma

OBJECTIVE

To investigate the frequency of apoptosis and expression of metallothionein (MT) protein and to clarify their roles in renal cell carcinoma (RCC).

MATERIALS AND METHODS

Apoptosis was detected by using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end labelling (TUNEL) technique in 70 formalin-fixed and paraffin-embedded RCC specimens. The expression of MT was determined immunohistochemically.

RESULTS

The incidence of apoptosis was significantly higher in grade 2 and 3 RCC than in grade 1. There were no significant differences amongst the other categories of RCC when grouped by tumour stage, cell type and growth pattern. The expression of MT was detected in 23 of 70 (33%) RCCs. Subcellularly. MT was localized in the cytoplasm, nucleus and cell membrane of RCC. Statistical analysis showed a close association of MT expression with the higher grades and invasive growth pattern of RCC. In addition, the incidence of apoptosis increased with increasing immunoreactivity of MT staining. There was a significant difference in the incidence of apoptosis between the diffuse staining and negative staining of MT.

CONCLUSIONS

There were close associations of higher grade RCC with both the incidence of apoptosis and the expression of MT, as well as a close relationship between MT expression and the invasive growth pattern of RCC. This suggests that the involvement of apoptotic cell death and MT expression should be considered an important factor in the process of the renal carcinogenesis and tumour progression.

Increased apoptosis during papilloma development in mice susceptible to tumor progression

Programmed cell death (apoptosis) is known to occur not only during normal development and tissue remodeling but also during neoplasia. Despite the suggested role of apoptosis in preventing the proliferation of malignant cells, a positive correlation between tumor progression and the presence of apoptotic cells has been found in different types of cancer, including epithelial tumors. In normal mouse skin, the role of apoptosis is not completely understood, and it has been suggested that terminal differentiation may be a special case of apoptosis. In the work reported here, we counted apoptotic cells in mouse skin tumors generated with a two-stage chemical carcinogenesis protocol. We analyzed papillomas from outbred SENCAR mice at different times during promotion, and to better determine the correlation between apoptosis and tumor progression, we compared papillomas generated from two inbred strains derived from the SENCAR stock that differ in their susceptibility to tumor progression. Our results showed that in mouse skin chemical carcinogenesis, the number of apoptotic cells was greater in papillomas that may have been in the process of progressing to squamous cell carcinomas. This conclusion is also supported by the fact that papillomas from SENCAR P/Bt. mice, a tumor progression-susceptible strain derived from outbred SENCAR mice, had more apoptotic cells than papillomas from progression-resistant SSIN mice.

Proliferative activity and p53 protein accumulation correlate with early invasive trend, and apoptosis correlates with differentiation grade in oesophageal squamous cell carcinomas

Using oesophageal squamous cell carcinoma samples of both intramucosal and advanced types, proliferative activity (Ki-67 labelling index), p53 protein accumulation and apoptosis (in situ DNA nick end labelling) were assessed, and the relation of these values to progression or differentiation grade of tumours was analysed. In terms of proliferative activity and the proportion of positive cases with p53 accumulation, a statistically significant difference was demonstrated between intraepithelial carcinomas and intramucosal carcinomas with stromal invasion (17.2% vs 31.7% for the Ki-67 labelling index, and 23.5% vs 67.4% for the proportion of positive cases of p53 accumulation). Values for the latter were almost comparable to those of advanced carcinomas. Immunohistologically, Ki-67 positive, proliferating cells were distributed preferentially in the peripheral fronts of invading nests. Apoptotic cells were observed in the inner areas of the invading nests of the intramucosal carcinomas with stromal invasion and in more advanced lesions, but were rarely observed in the normal epithelium or intraepithelial carcinomas. Apoptotic cells were seen mainly around areas of keratinization, and the apoptotic cell index was higher in well and moderately differentiated types of advanced carcinomas than in the poorly differentiated type (2.59% vs 1.09%). An increase in proliferative activity and an accumulation of p53 protein are associated with the onset of early carcinomatous invasion, while apoptosis is closely linked with the differentiation grade of carcinoma cells.

Apoptosis and proliferative activity of non-Hodgkin's lymphomas: comparison with expression of bcl-2, p53 and c-myc proteins

In order to clarify the role of spontaneous apoptosis of non-Hodgkin's lymphomas in the growth regulation system, apoptotic indices (AI) assessed by DNA nick end-labeling and proliferative activity, estimated in terms of KI-67 labeling indices (KI) and mitotic indices (MI), were compared. In addition, expression of bcl-2, p53 and c-myc was also examined in relation to these indicators. For this study, 103 lymphoma cases were used, comprising 72 of B cell and 31 of T cell origin (42 nodal and 62 extranodal). AI, KI and MI were significantly increased in line with bcl-2 negativity and p53 positivity, and there was no relation to the T, B cell classification or expression of c-myc. These indicators positively correlated overall. Positive correlation was stricter in groups believed to represent a good prognostic predictive factor, such as B cell origin, bcl-2(+), p53(-) and c-myc(-). Significant cross-correlation was noted only between bcl-2 versus T, B cell classification. However, no inverse correlation between bcl-2 and p53 was evident. These results suggest, in non-Hodgkin's lymphomas, that apoptosis plays an important role together with proliferative activity in counter-balancing tumor volume, and is strictly linked to bcl-2 expression, less so to p53 expression, but independent of T, B cell classification and c-myc expression. Apoptotic indices may be a predictive indicator for prognosis similar to proliferative activity.

Bcl-2 expression is correlated with a low apoptotic index and associated with progesterone receptor immunoreactivity in endometrial carcinomas

A total of 103 endometrial carcinomas (endometrioid type), as well as 15 samples of normal (atrophic or proliferative phase) and 26 of hyperplastic endometrium, were immunohistochemically investigated for expression of Bcl-2, and oestrogen and progesterone receptors (ER and PR), and the results compared with findings for apoptosis and cell proliferation. Carcinoma cases were subdivided into tubular and solid components on the basis of tumour growth patterns. Immunopositivity for Bcl-2, ER, and PR in tubular components was significantly higher than in the solid category, being negatively associated with histological grading. Immunoreactivity scores revealed that Bcl-2 in the tubular group was positively correlated with PR but not ER, while its expression in normal and hyperplastic endometrium was closely linked with both. Apoptotic and mitotic indices (AI and MI) were both significantly lower in tubular than in solid areas. In the tubular areas, AI, values were significantly lower in the subgroup with a high level of Bcl-2 expression than in either low-level or negative groups. These results indicate that Bcl-2 expression may play a central role in the inhibition of apoptosis in endometrial carcinoma, in particular those cases with tubular components, possibly being associated with PR rather than ER. Changes in the propensity for apoptosis may be related to alterations of tumour growth pattern and of features of differentiation.

Bcl-2 expression and allelic loss of the p53 gene in gastric carcinomas

In order to clarify the association between bcl-2 protein (Bcl-2) expression and genetic alteration, we investigated p53 and DCC (deleted in the colon carcinoma gene locus) gene abnormalities in Bcl-2-positive and -negative gastric carcinomas using a polymerase chain reaction/loss of heterozygosity (LOH) assay. Bcl-2 immunoreactivity was found in 25 of 178 (14%) gastric carcinoma cases. With these 25 positive cases, the proportion 18/87 (20.6%) of the total in early stages demonstrating invasion of the mucosa and/or submucosa was significantly greater (P = 0.013) than the 7/91 (7.7%) found for advanced tumors exhibiting invasion into or through the muscularis propria. However, there was no statistically significant variation between the proportions for differentiated (17/98 cases, 17.3%) and undifferentiated (8/80 cases, 10%) lesions. Sixteen Bcl-2-positive cases (9 cases were not studied because of insufficient specimen material to allow extraction of DNA) and 31 cases randomly selected from a Bcl-2-negative group were analyzed for the presence of p53-LOH or DCC-LOH and for p53 by immuno-histochemistry. The minority of the Bcl-2-positive group had p53-LOH and were immunopositive for p53 (P = 0.033, P = 0.028 respectively), while no association was found in the Bcl-2-negative category. In contrast, there was no correlation at all between Bcl-2 expression and DCC-LOH although the number of informative cases analyzed was too small to allow definite conclusions. These results indicate that Bcl-2 may be predominantly expressed at an early stage in gastric carcinomas, possibly in negative association with p53 gene abnormalities.

Correlation of apoptosis with tumour cell differentiation, progression, and HPV infection in cervical carcinoma

AIMS

To clarify the significance of apoptosis in the progression of uterine cervical neoplasias, including cervical intraepithelial neoplasia (CIN), microinvasive carcinoma (MIC), and invasive squamous cell carcinoma (ISCC) categories, in relation to cell proliferation and human papilloma virus (HPV) infection.

METHODS

Forty six cases of CIN I/II, 75 of CIN III, 16 of MIC, and 44 of ISCC were examined using formalin fixed and paraffin wax embedded samples. The TdT mediated dUTP-biotin nick end labelling (TUNEL) method for detection of apoptotic cells was performed along with Ki-67 immunohistochemistry. Presence of HPV-DNA was confirmed by PCR-RFLP assay.

RESULTS

Apoptotic labelling indices, calculated after counting positive nuclei among at least 2000 nuclei, showed significant positive correlation with histological malignant grading in CIN and tumour cell invasion into stroma. In contrast, similar Ki-67 labelling index values were found in CIN, MIC, and ISCC. Although HPV-DNA was detected in 35/46 CIN I/II (76.1%), 53/74CIN III (71.6%), 9/16 MIC (56.3%), and 36/44 ISCC (81.8%), there was no apparent relation with the apoptotic labelling indices.

CONCLUSIONS

Apoptosis in cervical neoplasias may be closely related to tumour cell differentiation and progression. It also seems unlikely that HPV itself is directly related to pathways regulating apoptosis.

Apoptosis and gastrointestinal pharmacology

Apoptosis is a fundamental biological process that regulates cell number and removes cells that are neoplastic or infected by viruses. This review summarises present knowledge of the mechanisms and genetic regulation of apoptosis in the gastrointestinal tract and highlights areas of pharmacological relevance. In the intestine, apoptosis occurs in the crypt and possibly at the villus tip. Abnormal apoptosis plays a role in a number of gastrointestinal disease including colorectal cancer. The effects of cytotoxic drugs, chemical carcinogens, nonsteroidal anti-inflammatory drugs, short-chain fatty acids, bile salts and anthraquinolones on apoptosis in the gastrointestinal tract are reviewed.

Enhanced cellular proliferative activity and cell death in chronic thyroiditis and thyroid papillary carcinoma

For the analysis of cellular proliferative activity and cell death in thyroid diseases, the Ki-67 labeling index, bcl-2 protein expression and cell death of follicular epithelia by immunohistochemistry and in situ DNA nick-end labeling methods were evaluated in normal thyroid tissues as well as in surgical specimens from cases of Hashimoto's disease (16 cases), focal lymphocytic thyroiditis (13 cases), Graves' disease (15 cases), follicular adenoma (20 cases) and papillary carcinoma (43 cases). Cellular proliferative activity and cell death were both enhanced in cases of thyroiditis, including Hashimoto's disease and focal lymphocytic thyroiditis. Thyroids from patients with follicular adenoma and papillary carcinoma also showed increased cellular proliferative activity and cell death. In addition, predominant high cellularity and partial loss of bcl-2 protein expression in papillary carcinoma suggested that the overgrowth and dedifferentiation were associated with malignancy.