A prediction model for breast cancer recurrence after adjuvant hormone therapy.

Hormone therapy with tamoxifen has long been the established adjuvant treatment for node-positive, estrogen-receptor-positive breast cancer in postmenopausal women. Since 30-40% of these patients fail to respond, reliableoutcome prediction is necessary for successful treatment allocation. Using pathobiological variables (available in mostclinical records: tumor size, nodal involvement, estrogen and progesterone receptor content) from 596 patients recruitedat a comprehensive cancer center, we developed a prediction model which we validated in an independent cohort of 175patients recruited at a general hospital. Calculated at 3 and 4 years of follow-up, the discrimination indices were 0.716[confidence limits (CL) 0.641, 0.752] and 0.714 (CL 0.650, 0.750) for the training data, and 0.726 (CL 0.591, 0.769) and0.677 (CL 0.580, 0.745) for the testing data. Waiting for more effective approaches from genomic and proteomic studies, amodel based on consolidated pathobiological variables routinely assessed at relatively low costs may be considered as thereference for assessing the gain of new markers over traditional ones, thus substantially improving the conventional use ofprognostic criteria.

Interchangeability and diagnostic accuracy of two assays for total and free prostate-specific antigen: two not always related items.

The variation between different PSA assays seems to influence the interpretation of individual PSA values and the clinical decisions about prostate cancer. One reason for this variability could be the different reactivity of antibodies for the various molecular forms of serum PSA; as a result, samples containing the same amount of tPSA but different proportions of fPSA can produce very different values. In this study, serum samples were collected prospectively from 152 consecutive patients referred to 2 institutions (Regional Hospital, Venice, 90 subjects; San Bortolo Hospital, Vicenza, 62 subjects) for PSA elevation and/or symptoms. Serum samples were assessed according to the manufacturers' instructions on the following 2 analyzers: the Immulite 2000 assay (Diagnostic Products Corporation, Los Angeles, USA), which measures tPSA and fPSA, and the ADVIA Centaur (Bayer Diagnostics, Tarrytown, USA), which assays tPSA and cPSA. cPSA values were transformed into fPSA by the equation fPSA=tPSA-cPSA. When taking Immulite tPSA and f/tPSA values as 100%, ADVIA Centaur values were 92.6% and 122%, respectively, which means that 20% of patients would be classified differently according to the traditional biopsy cutoff. In conclusion, there are considerable differences between the 2 methods, which could affect clinical decisions.

Prognostic significance of vascular endothelial growth factor protein in node-negative breast carcinoma.

BACKGROUND: The clinical outcome is generally positive for patients with node-negative breast carcinoma (i.e., those who do not have detectable metastases in the lymph nodes) who have been treated with surgery or surgery plus radiation therapy. In about 30% of the patients, however, the disease recurs, and they are at risk of death. Determination of valid new prognostic indicators would improve the ability to identify patients at high risk of recurrence. Breast cancer can entail substantial development of new blood vessels within the tumor tissue, and it is known that the growth and metastasis of solid tumors are dependent on such angiogenesis. The conversion of tumor cells to an angiogenic phenotype may be preceded by a change in the balance of angiogenic growth factors and angiogenesis inhibitors. PURPOSE: This study was conducted to determine if the levels of vascular endothelial growth factor (VEGF) protein, a potent endothelial growth factor and mediator of vascular permeability and angiogenesis, measured in the primary tumors of women with node-negative breast cancer are associated with known prognostic factors and patient survival. METHODS: By use of a selective enzymatic immunoassay, levels of VEGF protein were measured in cytosolic extracts of primary tumor tissue surgically obtained from 260 women with node-negative breast carcinoma who had been treated with surgery with or without radiation therapy but not with adjuvant therapy and who had been followed for a median time of 66 months. The relationships between VEGF concentrations and other prognostic dichotomous variables or clinical outcome were tested by the use of the Kolmogorov-Smirnov test and univariate and multivariate Cox analyses, respectively. The relationship between VEGF and hormone receptors (i.e., those for estrogen and progesterone) was examined by the use of Spearman's correlation analyses. All P values resulted from the use of two-sided statistical tests. RESULTS: Tumors from 247 (95%) of the 260 patients had detectable VEGF, ranging in concentration from 5.0 to 6523 pg/mg protein (median, 126.25 pg/mg protein). No statistically significant associations were found between VEGF and the other prognostic factors (e.g., age, menopausal status, histologic tumor type, tumor size, and hormone receptors) examined. Levels of VEGF were found to be prognostic for both relapse-free and overall survival in univariate and multivariate analyses (likelihood ratio tests; all four P values < .001). In the multivariate analysis, the first-order interaction term of VEGF and estrogen receptor was also prognostic for overall survival (likelihood ratio test; P = .05). CONCLUSIONS: The results show that cytosolic levels of VEGF in tumor tissue samples are indicative of prognosis for patients with node-negative breast carcinoma.

Detection of different estrogen receptor forms in breast cancer cytosol by enzyme immunoassay.

Estrogen receptors (ER) are routinely measured in tissue extracts from breast cancer using a radioligand binding assay (RBA) and an enzyme immunoassay (EIA). Although good correlation was found between the two methods, they are expected to measure, at least in part, different ER amounts in individual samples, because the RBA should detect unfilled ER only, whereas EIA should recognize both unfilled receptors and those filled by endogenous estrogens. The purpose of the present investigation was to evaluate if ER-EIA mainly detects ER filled by endogenous estrogens when using an estrogen-free buffer to dilute cytosol samples. Indeed, the commercially available EIA assay kit (ER-EIA; Abbott) is equipped with a sample dilution buffer containing a high concentration of 17beta-estradiol which should allow for the saturation of all the ERs. ER was measured in 57 cytosol samples from primary breast cancer with RBA and ER-EIA. In the latter case, samples were diluted using both the estradiol-rich dilution buffer of the kit and an estrogen-free low salt phosphate buffer. RBA and ER-EIA showed tightly correlated results. However, ER-EIA detected higher ER levels than RBA in the majority of cases. Results obtained by low salt ER-EIA were also correlated to both RBA and ER-EIA, showing, however, lower ER concentrations. ER levels measured by ER-EIA were not significantly different from the sum of ER concentrations found by RBA and low salt ER-EIA. These findings suggest that ER-EIA detects ER only in the conformational status that is achieved after saturation by estrogens. These findings were confirmed by sedimentation shift experiments, which showed that the monoclonal antibody D547 used in the kit binds ER in the occupied form only. This leads to the conclusion that ER-EIA detects functioning (in terms of binding with estradiol) ERs. From the present investigation, we suggest that it is possible and probably worthwhile to optimize the EIA method by using different buffers to measure: (a) the total number of ERs capable of binding estradiol; (b) the ER filled by endogenous estrogens; and (c) by difference, the unfilled ER concentrations.

High-titer HER-2/neu protein-specific antibody can be detected in patients with early-stage breast cancer.

PURPOSE: To evaluate HER-2/neu-specific antibody immunity in patients with breast cancer, to determine the rate of occurrence of serum antibodies to HER-2/neu in patients with breast cancer, and to relate the presence of specific immunity to overexpression of HER-2/neu protein in primary tumor. METHODS: The antibody response to HER-2/neu protein was analyzed in 107 newly diagnosed breast cancer patients. Sera was analyzed for the presence of HER-2/neu-specific antibodies with a capture enzyme-linked immunosorbent assay (ELISA) and verified by Western blot. Sera from 200 volunteer blood donors was used as a control population. RESULTS: The presence of antibodies to HER-2/neu correlated with the presence of breast cancer. HER-2/neu antibodies at titers of > or = 1:100 were detected in 12 of 107 (11%) breast cancer patients versus none of 200 (0%) normal controls (P < .01). The presence of antibodies to HER-2/neu also correlated to overexpression of HER-2/neu protein in the patient's primary tumor. Nine of 44 (20%) patients with HER-2/neu-positive tumors had HER-2/neu-specific antibodies, whereas three of 63 (5%) patients with HER-2/neu-negative tumors had antibodies (P = .03). The antibody responses could be substantial. Titers of greater than 1:5,000 were detected in five of 107 (5%). CONCLUSION: The presence of HER-2/neu antibodies in breast cancer patients and the correlation with HER-2/neu-positive cancer implies that immunity to HER-2/neu develops as a result of exposure of patients to HER-2/neu protein expressed by their own cancer. These findings should stimulate further studies to develop the detection of immunity to oncogenic proteins as tumor markers, as well as the development and testing of vaccine strategies to induce and augment immunity to HER-2/neu for the treatment of breast cancer or prevention of recurrent disease.

Comparison between two methods in the determination of circulating chromogranin A in neuroendocrine tumors (NETs): results of a prospective multicenter observational study.

Several methods for analyzing CgA using either monoclonal or polyclonal antibodies have been developed, which differ in their diagnostic performance. The present paper describes the results of a prospective multicenter study aimed at comparing the clinical value of the two most widely used commercially available CgA assay kits in patients affected by neuroendocrine tumors (NETs). Two hundred sixty-one patients from 40 different centers and 99 healthy subjects were evaluated. CgA levels were measured with two different methods, a two-step immunoradiometric assay (IRMA) and an enzyme-linked immunosorbent assay (ELISA). CgA was measured centrally by two reference laboratories, one of which used IRMA and the other ELISA, and it was measured by the participating institutions with the method routinely used by each of them. The major findings of the present study were: (i) the two assays for the determination of CgA present good diagnostic performance; (ii) both assays are robust and guarantee comparable results when applied in different settings (central vs local laboratory); (iii) the negative/positive cutoff points (87 ng/mL for IRMA and 21.3 U/L for ELISA) were established according to standardized criteria; (iv) the results obtained with the two assays in basal clinical samples of patients affected by NETs show an apparently satisfactory correlation (rs = 0.843, p < 0.0001). However, a possibly clinically meaningful 36% discordance rate was found. These findings support the hypothesis that the two CgA kits might provide partially different information.

c-erbB-2/neu protein expression, DNA ploidy and S phase in breast cancer.

DNA content and c-erbB2/neu protein (p185) expression were evaluated by flow-cytometry and ELISA, respectively, in 166 specimens of primary breast cancer. A non-diploid DNA content was found in 88 tumours (53%), with the DNA index ranging from 0.7-2.7. S phase fraction (SPF) evaluation, performed in 130 cases, showed significantly higher values in aneuploid than in diploid tumours (median values, 17.3% and 5.8%, respectively). Thirty-six tumours (21.6%) showed p185 overexpression, while 45 (27.1%) and 85 (51.3%) showed intermediate and low expression, respectively. A good correlation (P = 0.0023) was found between DNA content and p185 positivity. Tumours with high p185 values were mainly aneuploid, while tumours with intermediate or low expression had variable degrees of DNA content. Furthermore, p185 concentration was significantly higher in aneuploid than in diploid tumours (P = 0.009). The highest rate of p185 (+) cases and the highest p185 concentrations occurred in triploid (1.3 < D.I. < or = 1.7), compared to the other tumours. SPF values and p185 positivity rates were not significantly correlated in diploid and in aneuploid tumours.

Co-determination of the angiogenic factors thymidine phosphorylase and vascular endothelial growth factor in node-negative breast cancer: prognostic implications.

Experimental and clinical studies have shown that human breast cancer is an angiogenesis-dependent neoplasm. In fact, several authors have demonstrated that the determination in primary tumors of the degree of vascularization (microvessel counts) as well as of some angiogenic peptides is of prognostic value. However, which are the most important mediators of angiogenesis and their relationship with other relevant biological markers needs further investigation. In the series of 260 women with node-negative breast cancer (NNBC) on which we previously assessed vascular endothelial growth factor (VEGF), we have now also determined thymidine phosphorylase (TP) protein as well as p53 protein and Cathepsin-D cytosolic levels using immunometric methods. The median concentrations of TP, p53 and Cathepsin-D were 105.4U/mg (range 1.2-843.1), 0.22 ng/mg (range 0.0-41.65) and 33.80nmol/mg (range 4.20-216.0), respectively. We found that TP concentrations were associated with Cathepsin-D and p53, but not with VEGF. VEGF (p<0.0001) and p53 (p = 0.03 and p = 0.012, respectively) were found to be statistically significant prognostic variables for both relapse-free survival (RFS) and overall survival in univariate analysis. Conversely, TP and Cathepsin-D levels did not correlate with prognosis. In multivariate analysis for RFS, VEGF levels (p<0.0001), TP levels (p = 0.050) and their first-order interaction terms (p = 0.027) were statistically significant prognostic indicators. Cathepsin-D and p53 protein levels did not retain significance in the model inclusive of all the above variables. The predictive capability of the complete model was satisfactory (Harrell c statistic = 0.72). Moreover, these results suggest a possible potentiation of the capability of predicting the likelihood of recurrence by the co-determination of TP and VEGF. The probability of recurrence was particularly high in the patients with primary tumors characterized by elevated levels of both angiogenic factors. This is the first study showing in vivo that two different angiogenic peptides concur in the progression of human breast cancer. The biology and possible therapeutic implications of this observation are discussed.

Blood glutathione as a surrogate marker of cancer tissue glutathione S-transferase activity in non-small cell lung cancer and squamous cell carcinoma of the head and neck.

The identification of markers predicting the response to therapy is of the utmost importance in oncology. Several authors have suggested that increased levels of glutathione (GSH) and glutathione S-transferase (GST) activity might be meaningful predictors of poor responsiveness to chemotherapy in several human cancers, but the biological assays have not been standardised and published studies show conflicting evidence. The aim of the present study was to select a validated panel of tests to assess the GST/GSH system in a clinical setting. Matched blood and tissue samples (normal and malignant) from 52 cancer patients with either non-small cell lung cancer (NSCLC) or head and neck squamous cell carcinoma (SCCHN) were investigated. GSH levels and GST activity were higher in cancer tissues than in matched normal tissues in both malignancies. The difference was statistically significant in NSCLC (P=0.0004 and P=0.0002, for GSH and GST, respectively) and borderline in SCCHN (P=0.03 and P=0.02, for GSH and GST, respectively). Moreover a strong correlation was found between the GSH level in whole blood and GST activity in cancer tissue in both malignancies (P=0.003, r=0.53 in NSCLC, P<0.0001, r=0.89 in SCCHN). In conclusion, reliable and robust methods for routine use in tissue extracts and in whole blood have been validated. Our finding regarding the GSH level in blood indicates that circulating GSH could have a clinical relevance as a surrogate marker of GST activity in tumour tissue.

Comparison between single saturating dose ligand binding assay and enzyme immunoassay for low-salt extractable oestrogen and progesterone receptors in breast cancer: a multicentre study.

An excellent correlation between ligand binding assay (LBA) and enzyme immunoassay (EIA) for both oestrogen (ER) and progesterone (PR) receptors has been reported. Nevertheless, considering that the clinical value of any discrepancy between LBA and EIA probably varies with the receptor level, we undertook a collaborative study in which a single saturating dose (SSD) LBA and EIA were compared in different ER and PR dose ranges. The values of ER measured by EIA were higher in tumours with low or intermediate receptor content, causing a misclassification of ER status in 9% of cases (ER+: 77.5%, EIA, 68.8% SSD). In the case of ER, EIA values tended to be higher than SSD in all centres. For PR, EIA and SSD were generally more comparable (PR+: 66.0% EIA, 72.0% SSD, discordance rate 6%), with EIA showing, however, different trends in different centres. PR concentration was not significantly different in ER SSD-/EIA+ and in ER SSD+/EIA+ cases, suggesting that EIA detects at least in part integer ER. We conclude that although EIA may be a reliable methodological alternative to SSD, the two methods are not interchangeable until effective cut-off levels for clinical decisions are assessed for EIA.

Relationship between cathepsin D and other pathological and biological parameters in 1752 patients with primary breast cancer.

The relationship between cathepsin D and other pathological or biological prognostic parameters has not yet been defined through systematic studies in breast cancer. The aim of the present investigation was to define the relationship between cathepsin D and nodal status, tumour size, steroid receptors and tumour grade in a wide patient series. Cytosol cathepsin D was assayed with an immunoradiometric assay in tumour samples from 1752 patients. A statistically significant, but not biologically meaningful association was found between cathepsin D and both tumour size and grade. Cathepsin D was significantly higher in node-positive than in node-negative tumours. However, cathepsin D is not of great use in order to predict the risk of axillary metastases in individual patients, due to overlapping of cathepsin D values between node-positive and node-negative cases. A significant, direct association was found between cathepsin D and both oestrogen receptor and progesterone receptor cytosol levels. Nevertheless, preliminary data indicate that cathepsin D and steroid receptors provide independent prognostic information.

Prognostic role of serum CA15.3 in 362 node-negative breast cancers. An old player for a new game.

The aims of the present investigation were to evaluate the association between serum CA15.3 levels and other biological and clinical variables and its prognostic role in patients with node-negative breast cancer. We evaluated 362 patients operated upon primary breast cancer from 1982 to 1992 (median follow-up 69 months). Serum CA15.3 was measured by an immunoradiometric assay. The association between variables was investigated by a Principal Component Analysis (PCA) and the prognostic role of CA15.3 on relapse-free survival (RFS) was investigated by Cox regression models adjusting for age, oestrogen receptor (ER), tumour stage, and ER x age interaction, with both the likelihood ratio test and Harrell's c statistic. The prognostic contribution of CA 15.3 was highly significant. Log relative hazard of relapse was constant until approximately 10 (U/ml) of CA15.3 and increased thereafter with increasing marker levels. CA15.3 showed a significant contribution using as a cut-off point a value of 31 U/ml. However, the contribution to the model of the marker as a continuous variable is much greater. From these findings, we can conclude that: (i) CA15.3 is a prognostic marker in node-negative breast cancer; (ii) its relationship with prognosis is continuous, with the risk of relapse increasing progressively from approximately 10 U/ml.

Endogenous interleukin-12: relationship with angiogenic factors, hormone receptors and nodal status in human breast carcinoma.

Interleukin-12 (IL-12) is known to be a key cytokine for regulating immune response, but it is also known to provide some other biological function including inhibition of angiogenesis. We have determined using an enzymatic immunoassay the endogenous levels of IL-12 in 390 cytosols of primary breast cancers previously tested also for the angiogenic peptides, vascular endothelial growth factor (VEGF) and thymidine phosphorylase (TP). The concentration of IL-12 ranged from 0 to 7.6 ng/mg protein, and 124 (31.8%) out of 390 cancers showed a detectable dose (>0.1 ng/ml). There was no statistical association of IL-12 levels with tumor size and menopausal status. IL-12 levels tended to be higher in the tumors of node-positive patients as compared to those of node-negative ones (t-test, p=0.082). In addition, IL-12 levels were inversely associated with hormone receptor status, particularly progesterone receptor expression (p=0.0013). There was a significant inverse association between IL-12 and TP concentration (p=0.0007). The proportion of tumors with detectable levels of IL-12 and low levels of either VEGF or TP was higher among the patients with node-negative as compared to those with node-positive disease. On the contrary, the proportion of tumors with no detectable IL-12 and high levels of either VEGF or TP was higher in node-positive versus node-negative cancers. In conclusion, our study evaluated the balance between pro-angiogenic factors (TP and VEGF) and IL-12, as a detectable naturally occurring inhibitor of angiogenesis, in the same series of node-negative and node-positive breast cancers. Further studies are warranted to investigate the biological and clinical significance of the co-determination of pro and contra angiogenic factors in human breast carcinoma.

Epidermal growth-factor receptor and erbb2 protein in colorectal tissue - comparison between cancer and normal mucosa.

Epidermal growth factor receptor (EGFr) and p185neu protein were measured in 55 samples of carcinoma and 55 of normal colorectal mucosa from the same patient, using a ligand binding assay and an ELISA method respectively. The binding characteristics of EGFr were similar in cancer and normal tissue. The concentrations of both EGFr and p185 showed gaussian distribution and were not significantly different between normal and cancer tissue, although a trend toward higher levels of EGFr in normal mucosa was found. Moreover, no significative variations were found in the ratios between cancer and normal tissue after desaturation of the EGFr. No correlations were found between EGFr and p185 and the main clinopathological parameters.

Progesterone receptor determined by immunocytochemical and biochemical methods in human breast cancer.

Immunocytochemical assay (ICA) of the progesterone receptor (PgR) was performed on 152 patients with stage I-II breast cancer. We employed the rat monoclonal antibody KD-68 and a peroxidase/antiperoxidase displaying system. The results obtained by ICA (Pg(RICA)) were compared with those by the biochemical dextran-coated charcoal assay (PgRDCC). Comparing the two methods we found an overall agreement (accuracy) of 77.5%, a PgR(ICA) sensitivity of 83.5% and a specificity of 73%. Both methods were significantly associated with oestrogen receptor expression, detected by DCC (P less than 0.001 for PgRDCC and P = 0.0014 for PgR(ICA)). No significant association was found between PgR(ICA) or PgRDCC and the other clinicopathological features analysed. After a median follow-up of 36 months, the overall survival probability was 91% in PgRDCC-positive versus 81.5% in PgRDCC-negative patients (log-rank test, chi 2 = 0.91) compared to 87.5% in PgR(ICA)-positive versus 82% in PgR(ICA)-negative ones (log-rank test, chi 2 = 0.93). Disease-free survival probability was 74.5% in both PgRDCC-positive and PgRDCC-negative patients (log-rank test, chi 2 = 0.02) compared to 78% in PgR(ICA)-positive versus 71.5% in PgR(ICA)-negative cases (log-rank test, chi 2 = 0.37). The present study demonstrates that ICA is a reliable method to detect PgR, correlating well with the DCC assay. Moreover, the ICA assay seems to provide clinical information complementary to the biochemical method. The definition of its prognostic value in operable breast cancer needs additional studies, particularly in node-negative patients.

Epidermal growth-factor receptors and erbb2 protein expression in esophageal cancer and normal mucosa.

The epidermal growth factor receptor (EGFr) and the erbB2 protein (p185) concentrations were assessed in 31 esophageal cancer specimens and in the corresponding normal mucosa, in order to investigate the possible links with the main clinical and pathological parameters. Detectable and high affinity EGFr was found in 27/31 cancer and in 18/31 normal tissue samples. EGFr concentrations were not significantly different between cancer and normal tissue, although a trend toward higher levels in cancer was found. No relationships were found with histologic type, tumor bulk, lymph node status, pathologic stage, ploidy and type of surgical resection. A significant negative correlation between EGFr levels and overall survival was found. Detectable levels of p185 were found in all the tissues examined, but the expression was higher in adenocarcinoma than in squamous cell carcinoma samples. The EGFr role in malignant transformation still has to be established, but the determination could be of clinical use. As for p185, its role in the onset of esophageal cancer could be confined to the subgroup of the adenocarcinomas.

Dynamic use of tumor markers, rationale-clinical applications and pitfalls.

The dynamic evaluation of tumor markers is a promising area of investigation which is expected to provide clinical information when serial samples are available from the same patient. This is feasible in the post-operatory evaluation, during the follow-up after the treatment for to the primary tumor and in the monitoring of the treatment for metastatic disease. Variations among serial samples may be assessed using both empirical and mathematical approaches. Empirical approaches rely on overcoming a given percentage usually chosen on the base of arbitrary decisions. Mathematical approaches include the actual half-life, the doubling time, a dose/time regression analysis and the calculation of the critical difference. The two former are currently used in clinical practice whereas the two latter are still matter of investigation. As concerns the assessment of the radicality of the surgery for the primary tumor, the serum markers are used in germ cell tumors and in prostate cancer. The half-life of the markers is the decision criteria used in germ cell cancers, while in prostate cancer PSA is expected to be undetectable more than 30 days after the radical prostatectomy. Tumor markers are currently used during the follow-up of several malignancies after the treatment for primary tumor. Although several samples are available, decision criteria are still based on positive/negative cut-off values in several instances. Promising dynamic approaches are under investigation and are expected to lead to earlier and probably more accurate information concerning the disease progression. A critical point still under debate is the actual impact of tumor markers on patients' survival in malignancies incurable when metastatic, such as colorectal cancer and breast cancer. This matter urgently demands perspective clinical studies. Finally, the dynamic use of tumor markers is now commonly applied in the monitoring of the therapy for metastatic malignancies. In this clinical setting mathematical criteria are used for ovarian and and germ cell tumors with promising results. Nevertheless, the use of empirical criteria, namely the percentage of variation between two consecutive samples, is successfully used for the monitoring of the therapy of metastatic breast cancer. In conclusion, when several samples are available from an individual patient they may be evaluated according to dynamic criteria instead of referring to a conventional positive/negative cut-off point. Although mathematical decision criteria are expected to provide more reliable data, empirical approaches are used as well and provide useful information in decision making.

ErbB2 assay in breast cancer: possibly improved clinical information using a quantitative method.

ErbB2/neu protein (p185) expression was evaluated by ELISA in 115 breast cancer specimens. Distribution was subdivided in quartiles and showed a distinct behaviour in comparison with both clinico-biological parameters and clinical outcome. In particular, intermediate concentration groups showed a significantly better disease-free survival than the low and high concentration groups (p = 0.02). We classified the patients as "low risk" (64 samples with p185 concentrations between 2150 and 30000 U/mg of proteins) and "high risk" on the basis of the results of the multivariate analysis. The p185 grouped as described showed a significant relationship with the disease free survival in multivariate analysis. Although the data must be considered as preliminary, they suggest the possibility of identifying more appropriately the high risk patients through the biochemical determination of p185.

Immunoenzymatic assay of erbB2 protein in cancer and non-malignant breast tissue. Relationships with clinical and biochemical parameters.

The erbB2-encoded protein p185 was determined in 130 breast cancer specimens and in 29 non-malignant breast tissues using a recently available ELISA method. The assay showed good characteristics of precision and accuracy. In the non-malignant tissue p185 concentrations were normally distributed and directly correlated with estrogen receptors (ER) and progesterone receptors (PR). In cancer tissue p185 showed higher concentrations than in non-malignant tissue. No relationships were found between p185 and the main clinical and pathological parameters, except that a direct association with nuclear grade was found. We have categorized the breast cancer samples according to p185 concentrations as p185-negative (concentrations lower than the higher non-malignant tissue) and p185-positive. Our data suggested a different behaviour of p185 in samples with low or high p185 concentrations. Indeed, in p185-negative samples the concentrations were directly correlated with both ER and PR. Conversely, p185-positive samples were directly associated with node status and pT, and inversely associated with ER and PR.