Urokinase receptor and colorectal cancer survival

Letters to the Editor

Urokinase receptor and colorectal survival

cancer

system is actively involved in tumour invasion and metastasis. The factors that participate in the plasminogen activation cascade consist of and the urokinase-type (u-PA) tissue-type (t-PA) plasminogen activators and at least two inhibitors (PAI-1 and PAI-2) which regulate the conversion of plasminogen to the broad spectrum proteinase plasmin. In many human tumours an impressive increase in u-PA has been found to be associated with a less pronounced increase in the inhibitors PAI-1 and/or PAI-2. Moreover, recent survival studies identified u-PA, PAI-1, and PAI-2 as independent prognostic factors in disease-free or overall survival of patients with breast, gastric (Nekarda et al, Jan 8, p 117), and colorectal cancer.1-3 However, the activity of u-PA is regulated not only by the inhibitors but also by, perhaps more importantly, the urokinase receptor (u-PAR). Several studies indicate an enhanced expression of u-PAR in human malignancies by in-situ hybridisation, by immunohistology of tissue sections, or by antigen determination with a ligand (u-PA) binding or enzyme-linked immunosorbent assay (ELISA).4,5 We evaluated the contribution of the u-PAR antigen to 5-year overall survival in 161 patients with colorectal cancer. Representative parts of the completely resected tumours were extracted in Tris/HCl Tween 80 buffer (pH 7-5) and the supernatants were analysed for u-PAR content by a recently developed ELISA (American Diagnostica, Greenwich CT, USA). The tumours were classified according to the modified Dukes’ stage and histologically evaluated for differentiation grade. Clinical data such as age, sex, and tumour localisation were also registered. Optimum dichotomisation of the variables and univariate and multivariate analysis were done with Cox’s proportional hazards model and the EGRET statistical package (SERC,

SIR-The

plasminogen activation

Seattle, WA, USA).

Dukes’

Staget

Age‡ uPAR§

CD vs AB

3.2

2.0

C vs B B2 vs Bl C2 vsCl

(21-50, p<0.001) 2.5 (15-40, p<0.001) 2.0 (08-49, p=0.1) 2.5 (1.2-5-4, p=0.02)

(1.3-3.2, p=0.002) 2.3 (1.3-3.9, p=0.002) 4.1 (16-107, p=0.004) 1.5 (07-31, p=0.3)

2.6 (14-51,

p=0.004) 3.0 (1-4-6-3,

p=0.003) 1.8 (07-49, p=0.3) 10,8 (31-376, p<0.001)

Values are hazard ratios (95% CI, p value). *Other variables included were sex, and localisation and differentiation of tumour. tDukes’ stage: A n=7, 81 n=21, B2 n=59, Cl n=17, C2 n=37, D n=20. *--66.1 vs <66.1 yr. §4’1 vs <4.1 ng/mg protein.

Table: Multivariate colorectal cancer*

analysis of (sub)groups of patients with

Determination of the optimally discriminating u-PAR concentration in relation to the overall survival in the univariate analysis revealed an optimum at 4-11 ng/mg protein (figure). At this cut-off point a subgroup of patients was identified that had a significantly worse 5-year overall survival (2 of 13 patients [15’4%]) compared with the reference group (66 of 148 patients [44-6%]; data not shown). Multivariate analysis including sex, localisation of the tumour (left vs right side), and differentiation grade (poor vs moderate-well) revealed Dukes’ stage, age, and u-PAR concentration to be independent and significant prognostic factors for 5-year overall survival (table). Moreover, multivariate analysis of subgroups of patients according to Dukes’ stage identified the u-PAR concentration as an independent prognostic factor in the comparison of patients with Dukes’ stage C versus B and stage C2 versus C1 (survival of patients according to high vs low u-PAR 182% vs 48-8% and 0% vs 34-0%, respectively). In conclusion, this study shows that a high u-PAR concentration in colorectal tumours is an independent prognostic factor for 5-year overall survival. The identification of a high-risk group according to u-PAR values might also be applicable to other tumours such as breast and stomach. Eventually these high u-PAR high-risk patients might be treated by adjuvant therapy or perhaps even by urokinase receptor antagonists, given the important role of u-PAR in tumour invasion and metastasis.’ We thank Dr Johan H J M van Krieken (Department of Pathology), Dr Jan H Verheijen (TNO-PG), and Dr Cornelis J H van de Velde and Dr Kees Welvaart (Department of Surgery). This study was supported by a grant from the Dutch Cancer Society (NKB-KWF oaa 92-18).

Cornelis FM Sier, Martine M Heerding, Gerrit Griffioen, Cornelis B H W Lamers, Hein W Verspaget Department of Gastroenterology, University Hospital 1-C4P, 2333 AA Leiden,

SJam Ganesh, Netherlands

1

et al. Both the cytosols and detergent of breast cancer tissues are suited to evaluate the prognostic impact of urokinase-type plasminogen activator and its inhibitor, plasminogen activator inhibitor type 1. Cancer Res 1994; 54: 2527-30. Bouchet C, Spyratos F, Martin PM, et al. Prognostic value of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitors PAI-1 and PAI-2 in breast carcinomas. Br J Cancer 1994; 69: 398-405.

Jänicke F, Pache L, Schmitt M, extracts

Figure: Hazard ratios and p values according to univariate Cox’s analysis based on increasing cut-off values of u-PA receptor Dotted line indicates p=005.

2

401

3

4

Ganesh S, Sier CFM, Griffioen G, et al. Prognostic relevance of plasminogen activators and their inhibitors in colorectal cancer. Cancer Res (in press). Pyke C, Kristensen P, Ralfkiær E, et al. Urokinase-type plasminogen activator is expressed in stromal cells and its receptor in cancer cells at invasive foci in human colon adenocarcinomas. Am J Pathol 1991; 138: 1059-67.

5

Fazioli F, Blasi F. Urokinase-type plasminogen activator and its receptor: new targets for anti-metastatic therapy? Trends Pharmacol Sci

1994; 15: 25-29.

Effect of menstrual phase on treatment of breast cancer

surgical

SIR-Veronesi and colleagues’ report from the National Cancer Institute in Milan (June 18, p 1545) confirms the effect of timing of surgery in the menstrual cycle for women with operable breast cancer. The nature of the findings were broadly similar to those reported from Guy’s Hospital.’1 Despite acknowledging that the Milan study is the largest so far, Astrow in his accompanying commentary, was sceptical of the findings. Lack of survival data was one reason given for this scepticism. However, disparity between relapse-free and overall survival data is hardly ever seen in breast cancer, and the pattern of recurrence related to days in the menstrual cycle (figure 1 in Veronesi’s report) matches our

original report very closely. Astrow also cites conflicting reports from other centres as a reason for rejecting this finding. This argument reiterates that of McGuire, which has already been effectively refuted.2 To emphasise this point, we have carried out a meta-analysis of published work. We previously conducted a smaller overview in 1991 and showed that overall there was a significant effect of timing of this surgery. The larger metaanalysis includes the Milan results (figure). The overall effect of timing of surgery was significant (p=002), with an average odds reduction of 16% for treatment in the luteal phase of the menstrual cycle. The test for heterogeneity in the observed/expected deaths was significant (X2 test, p=0-000005), showing that the scatter of results is

Figure: Overview of published work on timing of surgery in cancer (5-year survival results)

breast

Individual studies with odds ratios and 99% Cis

publication.

402

are

ordered

by year of

normally distributed (four trials

have include an odds ratio of 1, which is equivalent to no effect). Thus there is a significant effect of timing of surgery averaged over all the studies, and there are differences between centres that cannot be explained as chance findings. We have discussed the findings with most of the authors of the studies in this overview. It is noteworthy that the large centres that have reported positive findings (Guy’s, NCI Milan, Memorial Sloan Kettering) all have a very structured approach to surgical management, with the use of tumour excision for primary diagnosis in most cases during the study period. Our recent finding that serum levels of progesterone at the time of diagnosis had a prognostic impact is further evidence of the importance of timing of surgery.3 On the basis of this overview, surgeons should consider altering their practice now. If still unconvinced, they should register all premenopausal patients in prospective studies. An answer to this question is needed as soon as possible, since it could potentially save a substantial number of lives.

unexpected

and

not

99% CI which do

not

Ian S Fentiman, W M ICRF Clinical

1

2 3

Gregory, M A Richards Oncology Unit, Guy’s Hospital, London SE1 9RT,

UK

Badwe RA, Gregory WM, Chaudary MA, et al. Timing of surgery during menstrual cycle and survival of premenopausal women with operable breast cancer. Lancet 1991; 337: 1261-64. Gregory WM, Richards MA, Fentiman IS. Optimal timing of initial breast cancer surgery. Ann Intern Med 1992; 116: 268-69. Badwe RA, Wang DY, Gregory WM, et al. Serum progesterone at the time of surgery and survival in women with premenopausal operable breast cancer. Eur J Cancer 1994; 30A: 445-48.

SIR-We were puzzled that Veronesi and colleagues in their report of the Milan study draw an inference from their findings in breast cancer patients that is at variance with current understanding of the metastatic process. The fact that menstrual cycle timing seemed to have an effect only in patients with node-positive disease does not suggest that the effect is due to interference with the involved lymph-nodes. Involved nodes are an indicator of invasive and metastatic potential, and are therefore commonly associated with tumours that display properties known to be necessary for this process, such as expression of relevant adhesion molecules or enzymes, some of which Astrow discusses. Such cells may be more likely to be shed into the circulation during removal of the primary tumour, or might have better survival potential once shed, and modulation of either of these by hormonal fluctuations would account for Veronesi and colleagues’ findings without the need to postulate a role for metastasis from lymph-node metastases. The importance of cell shedding during cancer surgery remains neglected, principally because it does not accord with present emphasis on the importance of the properties rather than the number of cells shed. There is no logical reason for dismissing as unimportant the increased cell shedding during tumour handling, which has been known for many years to be associated with increased metastasis in animals.’ The neglect of this factor can be partly explained by the failure of earlier efforts to show increased cell shedding during cancer surgery in women, which fell into disrepute when the techniques used were invalidated.2 We have completed investigation of 18 women having operations for primary breast cancer. A fine catheter was placed in the third part of the ipsilateral subclavian vein via an antecubital approach, with radiological control. Blood samples were withdrawn before, during, and 24 h after surgery. Tumour cells were detected by differential density centrifugation and cytospin preparation followed by immunocytochemical staining with MNF116, an anti-