Tissue-type plasminogen activator (tPA) in breast cancer: relationship with clinicopathological parameters and prognostic significance

BACKGROUND

Tissue-type plasminogen activator (tPA) is a serine protease primarily involved in the intravascular dissolution of blood clots. High intratumoral tPA levels are associated with prognosis in several human tumors. In addition, tPA has been shown to be an estrogen-inducible protein in human breast cancer cell lines. The aim of the present study was to analyze the cytosolic tPA content in primary breast carcinomas and its potential clinical value.

MATERIALS AND METHODS

tPA was measured by a solid-phase enzyme immunoassay in tumor cytosol samples obtained from 800 patients with breast cancer. The median follow-up period was of 49.2 months.

RESULTS

Cytosolic tPA levels ranged widely in breast carcinomas (median: 3.9; range: 0.1- 315.3 ng/mg protein). tPA levels were significantly lower in large tumors, as well as in those showing poor differentiation, estrogen (ER) or PgR-negativity, aneuploidy, or a high S-phase fraction. In addition, low tPA intratumoral levels were associated with a high probability of both shortened relapse-free and overall survival in all patients and in the subgroup with node-negative tumors. However, our results did not show any significant relationship between intratumoral tPA levels and prognosis in the different subgroups of patients, stratified according to the type of systemic adjuvant therapy received (chemotherapy, tamoxifen or chemotherapy plus sequential tamoxifen).

CONCLUSION

The results of the present investigation indicate that low intratumoral tPA levels are associated with aggressiveness and poor prognosis in breast cancer patients. However, the study suggests that tPA levels do not predict response to systemic adjuvant therapy.

Clinical Significance of Epidermal Growth Factor Receptor Content in Gastric Cancer

The objective of this work was to evaluate the epidermal growth factor receptor (EGFR) content in gastric cancer, its possible relationship with clinicopathological parameters of tumors and its prognostic significance. Membranous EGFR levels were examined by radioligand binding assays in 110 patients with gastric cancer. The mean follow-up period was 30.7 months. EGFR levels of tumors ranged widely, from 0.3 to 510 fmol/mg protein. EGFR levels were significantly higher (p<0.0005) in neoplastic tissue than in paired adjacent mucosa samples (median) (n= 84; 8.7 vs. 3.9 fmol/mg protein). Intratumoral EGFR levels were significantly correlated with tumor stage (p<0.05), and were higher in patients with stage III tumors (median) (7.6, 6.4, 12.3 and 7.5 fmol/mg protein for stages I, II, III and IV, respectively). In addition, the tumor/mucosa ratios of the EGFR content were significantly higher (p<0.05) in patients with stage III tumors (1, 1.8, 3.9, and 0.92, respectively). Although there was no significant relationship between EGFR levels of tumors and overall survival, the results suggest a role for EGFR in tumor progression of gastric cancer.

Estrogen and Progesterone Receptors in Colorectal Cancer and Surrounding Mucosa

In this prospective study we have quantified by means of ELISA-methods the cytosolic content of estrogen (ER) and progesterone receptors (PgR) in tumoral tissue and paired normal mucosa from 163 patients with resectable colorectal cancer. Survival analysis was performed in a subgroup of 120 patients and the mean follow-up period was 24.9 months. The cutoff for ER and PgR levels was set at 1 fmol/mg protein. On the basis of this cutoff 20.9% of the cancers were ER positive and 25.8% were PgR positive; normal adjacent tissue presented ER in 18.4% and PgR in 24.5%. Our results did not show any significant correlation between ER and PgR levels in neoplastic tissues. Howewer, a correlation was found in normal mucosa samples (p=0.02). Statistical analysis showed that there was no correlation between tumor ER and PgR content and patient age or sex, tumor location, Dukes’ stage, histological differentiation, DNA ploidy status and S-phase fraction. Furthermore, the results did not show any statistical differences in relapse-free and overall survival curves calculated for patients classified according to the hormone receptor content of their tumors.

ER and PgR were detected at low levels in normal and neoplastic colorectal tissues without any significant relationship to either clinicopathological tumor characteristics or patient outcome. Their possible role in colorectal cancer remains to be elucidated.

Prognostic significance of tissue-type plasminogen activator (tPA) content in gastric cancer and surrounding mucosa

AIMS

We analyzed the tPA content in primary gastric carcinomas and surrounding mucosa in order to assess the relationship between tPA content, clinicopathological tumor characteristics, and estrogen and progesterone receptor content. We evaluated the prognostic value of this serine protease in gastric cancer patients.

PATIENTS AND METHODS

122 resected gastric neoplasms and 95 adjacent mucosa samples were studied. The tPA content was measured in cytosol by an ELISA method. Cytosolic ER and PgR were measured with a solid phase enzyme immunoassay.

RESULTS

Cytosolic tPA levels in neoplastic tissues (median 1.0 ng/mg prot) were significantly lower (p=0.002) than those found in paired mucosa samples (median 2.3 ng/mg prot). There was no significant association between tPA levels and clinicopathological parameters or PgR content, but tPA levels were significantly correlated with ER content. The intermediate-tPA-content group, corresponding to samples with between 0.3 and 1.70 ng/mg protein, proved to have a significantly high risk of relapse.

CONCLUSIONS

We found a wide variability in tPA levels in gastric carcinoma and adjacent mucosa samples, with significantly decreased levels in tumors and a significantly positive relationship between tPA levels and ER status. There was a non-monotonic relationship between tPA levels and prognosis in patients with gastric cancer.

[Analysis of the cytosolic content of the pS2 protein in breast cancer]

OBJECTIVE

To analyze pS2 cytosolic levels in breast carcinomas and their correlation with different clinical characteristics of the patients and their tumours.

MATERIAL AND METHODS

Cytosolic pS2 levels were measured by radioimmunometric assay in tumours from 168 breast cancer patients.

RESULTS

The pS2 values ranged from 0 to 251 ng/mg protein (mean SD: 21.8 38.1; median: 7.9 ng/mg protein). These protein levels were significantly (p < 0.05) higher in premenopausal patients (27.6 45.2) than in postmenopausal patients (19.5 33.8). Intratumour pS2 levels were also significantly (p < 0.05) correlated with histologic grade of the tumours, and were higher in well diferentiated tumours (grade I: 28.8 42.8) than in moderately differentiated tumours (grade II: 19.7 35.6) and than in poorly differentiated tumours (grade III: 18.9 37.3). Similarly, significant differences in pS2 content were found between positive estrogen receptor (ER) tumours and ER-negative tumours (29.1 46.5 vs 11.3 15.9, respectively; p<0.0001), as well as between positive progesterone receptor (PR) tumours and PR-negative tumours (29.1 49.8 vs 15.3 21.5, respectively; p < 0.05).

CONCLUSIONS

The results suggest that pS2 may be a useful prognostic marker in breast cancer, and may also be useful to identify patients who are likely to benefit from hormone therapy.