Influence of the vascular endothelial growth factor-A (VEGF-A) 936C>T germinal polymorphism on tumoral VEGF-A expression in head and neck cancer patients (HNCP)

6050

Background: VEGF-A is a potent inducer of endothelial cell growth and tumor neo-vascularisation. We previously reported that tumoral VEGF-A expression is linked to overall survival in HNCP (Onesto et al. Br J Cancer 2006). The present purpose was to extend this study by analyzing VEGF-A gene polymorphisms since functional VEGF-A polymorphisms associated with serum VEGF-A and risk of cancer have been described. Methods: VEGF-A polymorphisms in position (relative to translation initiation) −2578C>A (promoter region), − 1498T>C (promoter region), −634G>C (5’UTR) and 936C>T (3’UTR) were analyzed (PCR-RFLP) in tumoral genomic DNA from 49 Caucasian HNCP (34 men, 15 women; 16 T1-T2, 33 T3-T4; 31% N0). Tumoral VEGF-A expression was measured with an ELISA kit. Results: Genotype distributions agreed with those predicted by the Hardy-Weinberg equilibrium. A linkage disequilibrium was observed between −2578C>A and −634G>C (p<0.001) as well as between −2578C>A and −1498T>C (p<0.001). Of note, tumoral VEGF-A expression was influenced by the 936C>T polymorphism, with a median at 540 pg/mg in CT+TT patients (N = 5) versus 940 pg/mg in CC patients (N = 44) (p = 0.064). VEGF-A expression was not related to any other polymorphisms. None of the analyzed polymorphisms was linked to node involvement or to tumor size. Unlike tumoral VEGF-A expression, the analyzed genotypes were not related to patient survival. Conclusions: In addition to the known influence of tumor hypoxia, the present data suggest that the 936C>T polymorphism can modulate tumoral VEGF expression, with the presence of the T allele associated with decreased VEGF-A expression. Determination of this germinal polymorphism may thus provide an easily accessible test that deserves further investigation as a potential factor to aid anti-angiogenic treatment selection.

No significant financial relationships to disclose.

Phenotypic and genotypic characteristics of epidermal growth factor receptor (EGFR) in colorectal cancer patients

4110

Background: Colorectal tumors express EGFR and are responsive to anti-EGFR therapies. However, there is no tumoral predictive factor for anti-EGFR therapy in colorectal cancer and EGFR gene copy number is currently a good candidate. The aim of this study was to examine relationships between EGFR germinal polymorphisms, EGFR gene copy number and EGFR expression. Methods: Eighty primary colorectal tumors were analyzed along with 39 normal mucosas. Tumor staging was : 4 stage 0, 13 stage I, 22 stage II, 23 stage III and 18 stage IV. EGFR -216G>T and -191C>A genotypes were analyzed by PCR-RFLP, CA-repeats polymorphism in intron 1 by fluorescent genotyping and gene copy number was measured by PCR amplification. EGFR expression was quantified with the reference Scatchard binding assay giving high- and low-affinity sites along with Kd values (Francoual M et al. Ann Oncol 17, 2006). Results: The number of CA- repeats varied from 14 to 21. Considered genotypes were superimposable between tumoral and normal tissues. A linkage disequilibrium was noted between -216G>T and -191C>A genotypes (p = 0.011). CA-repeats polymorphism and -216G>T genotype were not independent (p = 0.002). No relationship was observed between any of the analyzed EGFR genotypes and EGFR expression. EGFR expression was not related to gene amplification. EGFR gene amplification in tumor and normal tissue varied over a 4.7- and 2.9-fold range, respectively, and were not correlated. The mean value of the tumor/normal mucosa amplification ratio was 1.16 (range 0.55–2.68) and 14% of patients exhibited lower amplification in the tumor relative to the normal mucosa (ratio < 0.75). The mean ratio of high-affinity sites between tumor and normal mucosa was 1.20 (range 0.03–13.33). Conclusions: In colorectal tumors, neither EGFR gene amplification nor EGFR germinal gene polymorphisms influenced EGFR expression quantified with a specific ligand-binding assay.

No significant financial relationships to disclose.

Hand-foot syndrome (HFS) in patients receiving capecitabine: A pharmacological explanation

2019

Background: Use of the oral fluoropyrimidine capecitabine, which generates 5FU in tumor tissues, is currently expanding. HFS is frequently associated with administration of capecitabine. However, the underlying pharmacological mechanism of HFS is still not elucidated. In a previous experimental study, we ruled out a possible implication of 5FU catabolites (FUH2 and FBAL) in the etiology of HFS (Anti-Cancer Drugs 15: 969, 2004). The aim of this study was to investigate expression levels of thymidine phosphorylase (TP, the main activating enzyme of capecitabine) and dihydropyrimidine dehydrogenase (DPD, the rate-limiting enzyme of 5FU catabolism) in skin samples from the palm area of the hand (target zone) and from the back (control zone). Methods: Paired-skin biopsies have been planned in 12 healthy volunteers, in agreement with the local ethical committee. Expressions of TP, DPD, and Ki67 (cell proliferation marker) were analyzed by a two-step immunohistochemical method using specific monoclonal antibodies (from Calbiochem for TP, Roche for DPD and Dako for Ki67) and immunoperoxydase revelation (kit ABC Vectastain). Results: Data from the first four subjects indicate no significant difference in the strong Ki67 staining between control and target zones. TP was markedly expressed in the basal layer of the epidermis (BLE), with similar staining in control and target zones. Interestingly, in 3 cases out of 4, DPD was strongly expressed (2+, 3+) in the BLE of the control zone and much less (0, 1+) in the paired-target zone. Definitive data on 12 subjects will be presented. Conclusions: This preliminary original observation suggests that capecitabine may be locally activated in the skin due to high TP expression. The relative absence of DPD expression in the palm area may explain the specificity of HFS, which may result from a lack of local 5FU catabolism. These new data open the way to a possible pharmacological approach to limit HFS.

No significant financial relationships to disclose.

Enzyme-linked immunosorbent assay for pharmacological studies targeting hypoxia-inducible factor 1alpha

Hypoxia-inducible factor 1 (HIF-1) activates the transcription of a wide range of genes related to oxygen delivery and metabolic adaptation under hypoxic (low-oxygen) conditions. HIF-1 is, in fact, a heterodimer of two subunits, HIF-1alpha and HIF-1beta. The only analytical methods available for measuring HIF-1alpha levels in tumors are immunohistochemistry and Western blotting. Immunohistochemistry has the advantage of allowing the identification and direct examination of HIF-1alpha-expressing cells, but has the intrinsic limitation, as for Western blotting, of being nonquantitative. We developed and validated an enzyme-linked immunosorbent assay (ELISA) approach to measure HIF-1alpha levels in cultured tumor cell lines in vitro. HIF-1alpha was expressed in thirteen tumor cell lines grown under hypoxic conditions; however, the levels differed strongly between cell lines. These data point to intrinsic differences between cell lines for the induction of HIF-1alpha under hypoxic conditions. The ELISA developed in the present study is thus an interesting alternative to other analytical methods used to measure HIF-1alpha protein levels and should be useful in preclinical pharmacological studies targeting HIF-1alpha.

The relationship of epidermal growth factor receptor levels to the prognosis of unresectable pharyngeal cancer patients treated by chemo-radiotherapy

The aim of this study was to analyse prognostic factors for time to treatment failure (TTF) and overall survival (OS) in patients with unresectable cancer of the pharynx. A twice daily (b.i.d.) radiotherapy with concomitant cisplatin-5-fluorouracil chemotherapy was administered to 77 consecutive patients (68 males, 9 females; median age: 56 years). The studied factors were: age, gender, tumour differentiation, tumour volume, initial hemoglobin level, karnofsky index (KI), primary tumour location, T, N, epidermal growth factor receptor (EGFR) level in the tumour (fmol/mg protein). KI and EGFR level were significant predictors in a multivariate analysis for TTF (P=0.004 and P=0.0001) and OS (P=0.004 and P=0.0001). In order to select subgroups with different outcomes, a stratification of patients was performed based on the EGFR value: patients with tumour EGFR levels <35 fmol/mg protein, between 35 and 275 fmol/mg protein and >275 fmol/mg protein had 95%, 51% and 16% 3 year OS rates, respectively (log rank test; P=0.0001). Interestingly, for patients exhibiting a complete response (CR) after concomitant b.i.d. chemo-radiotherapy, patients with EGFR levels <35 fmol/mg protein were all alive at 3 years; in contrast, there was only 70 and 13% 3 year survival rates for patients with EGFR tumour levels between 35 and 275 fmol/mg protein and above 275 fmol/mg protein, respectively. EGFR determination appears to be a powerful prognostic parameter in unresectable pharyngeal cancer patients treated by concomitant chemo-radiotherapy.

Epidermal growth factor receptor expression in 780 breast cancer patients: a reappraisal of the prognostic value based on an eight-year median follow-up

PURPOSE

Because new therapeutic approaches target tumors expressing epidermal growth factor receptor (EGFR), the aim was to undertake a thorough analysis of the expression profile of EGFR in breast cancer and to reassess its prognostic value.

PATIENTS AND METHODS

Tumor EGFR levels were determined by a specific ligand binding assay in 780 consecutive breast cancer patients followed in our institute between 1980 and 1993. Mean age was 61 years (25-85 years). All patients had undergone tumor resection with axillary lymph node dissection: 373 patients (47.8%) underwent mastectomy, 37 (5%) subcutaneous mastectomy and 370 (47.2%) tumorectomy.

RESULTS

EGFR levels ranged between non-detectable up to 789 fmol/mg protein. EGFR median value was 9 fmol/mg protein and only a small proportion of patients exhibited a relatively marked EGFR expression. There was no link between tumor size, grade, node status and EGFR tumoral levels. There was a constant and significant decrease in EGFR tumoral levels according to patient age. A significant inverse relationship was found between estradiol receptors (ER) and EGFR. Median follow-up was 97 months with a minimum at 4 months and a maximum at 228 months. From univariate analysis it was found that histological grade, tumor size, node status and ER status were all significant predictors of survival, considering metastasis-free as well as overall survival. Using multivariable analysis, only histological grade, tumor size and node status remained independent predictors of survival.

CONCLUSION

EGFR determination is of limited value as a prognostic indicator in breast cancer.

Synergistic efficacy of 3n-butyrate and 5-fluorouracil in human colorectal cancer xenografts via modulation of DNA synthesis

BACKGROUND & AIMS

Butyrate, produced in the colon lumen, maintains mucosal cell homeostasis. Poorly diffusible, its access is compromised in growing colon cancers and absent in distant metastases. Butyrate regulates DNA synthesis. We postulated that systemic administration of butyrate should reduce colon cancer growth and enhance 5-fluorouracil (5-FU) efficacy.

METHODS

A stable derivative of butyrate (3n-But) was used. The antitumoral efficacy of 5-FU and 3n-But, alone or combined, was evaluated in human colorectal cancers (hCRCs) subcutaneously, orthotopically, or intrasplenically grafted into nude mice. Thymidylate synthase (TS) and thymidine kinase (TK) mRNA expression, proliferation, apoptosis, and cell cycle alterations were studied.

RESULTS

In vivo, 5-FU alone inhibited growth of only 3 of the 12 hCRCs tested and 3n-But alone had no effect; the 5-FU/3n-But combination inhibited growth of all 16 hCRCs tested. The hCRCs differed in their p53 and microsatellite instability status. 5-FU/3n-But decreased TK and TS mRNA expression by 20- and 40-fold, respectively, and TS activity by 75%, stopped cell proliferation without affecting cell differentiation, and significantly enhanced apoptosis. 3n-But potentiated the efficacy of Tomudex and methotrexate, 2 TS inhibitors, but not that of oxaliplatin. In vitro, 5-FU/3n-But inhibited [3H]thymidine but not bromodeoxyuridine incorporation and induced apoptosis in hCRC cell lines. Cells treated with 5-FU/3n-But did not accumulate in G1 nor in S phase of the cell cycle, while 5-FU and 3n-But arrested the cycle in S and in G1 phase, respectively. 3n-But prevented the cell rescue from 5-FU-induced cytotoxicity by uridine or thymidine.

CONCLUSIONS

3n-But and TS inhibitors acted synergistically against colorectal cancers, independently of the genetic alterations of the hCRCs. The mechanism of action of 5-FU/3n-But could be enhanced reduction of TS and prevention of thymidine salvage in DNA synthesis.

P53 determination alongside classical prognostic factors in node-negative breast cancer: an evaluation at more than 10-year follow-up

BACKGROUND

There is heterogeneity of methods and conflicting results concerning the prognostic value of p53 in node-negative breast cancer. The clinical value of a quantitative method for measuring tumoralp53 content still needs to be evaluated.

PATIENTS AND METHODS

A long-term retrospective study was conducted on 297 node-negative patients with a median follow-up greater than 10 years (11 years, 101-172 months). Classic prognostic factors were considered including age, tumor size, histoprognostic grade and estradiol (ER) and progesterone receptors (PR). In addition, the value of p53 determination (immunoluminometric assay in tumor cytosol) was assessed for this long follow-up period.

RESULTS

p53 concentrations were significantly linked to the histological grade (P = 0.001), to tumor size (P = 0.02) and ER status (P = 0.01). Higher p53 tumoral concentrations were found in tumors with large size, pejorative histological grade and negative ER status. In contrast, p53 tumoral concentrations were not influenced by menopausal or PR status. Multivariate Cox analysis demonstrates that tumor size was the only significant predictor of disease-free survival (P = 0.049) with a risk factor at 1.38. As regards specific survival, univariate Cox analysis indicates that p53 taken as a continuous variable is a significant predictor (P = 0.024) together with histological grade, tumor size and ER status. In a multivariate Cox analysis there were two significant and independent variables for predicting overall survival: tumor size (P = 0.031) and, ER status (P = 0.015) with the highest risk factor (RR = 2.14).

CONCLUSIONS

The present investigation points out that the prognostic power of p53 tumor determination evaluated at more than 10 years median survival is not higher than the well-recognized classic prognostic factors in node-negative breast cancer. The present data highlight the need to assess the prognostic value of potentially new biological factors in node-negative breast cancer on cohorts of patients followed over periods in excess of 10 years.

P53 determination alongside classical prognostic factors in node-negative breast cancer: an evaluation at more than 10-year follow-up

BACKGROUND

There is heterogeneity of methods and conflicting results concerning the prognostic value of p53 in node-negative breast cancer. The clinical value of a quantitative method for measuring tumoralp53 content still needs to be evaluated.

PATIENTS AND METHODS

A long-term retrospective study was conducted on 297 node-negative patients with a median follow-up greater than 10 years (11 years, 101-172 months). Classic prognostic factors were considered including age, tumor size, histoprognostic grade and estradiol (ER) and progesterone receptors (PR). In addition, the value of p53 determination (immunoluminometric assay in tumor cytosol) was assessed for this long follow-up period.

RESULTS

p53 concentrations were significantly linked to the histological grade (P = 0.001), to tumor size (P = 0.02) and ER status (P = 0.01). Higher p53 tumoral concentrations were found in tumors with large size, pejorative histological grade and negative ER status. In contrast, p53 tumoral concentrations were not influenced by menopausal or PR status. Multivariate Cox analysis demonstrates that tumor size was the only significant predictor of disease-free survival (P = 0.049) with a risk factor at 1.38. As regards specific survival, univariate Cox analysis indicates that p53 taken as a continuous variable is a significant predictor (P = 0.024) together with histological grade, tumor size and ER status. In a multivariate Cox analysis there were two significant and independent variables for predicting overall survival: tumor size (P = 0.031) and, ER status (P = 0.015) with the highest risk factor (RR = 2.14).

CONCLUSIONS

The present investigation points out that the prognostic power of p53 tumor determination evaluated at more than 10 years median survival is not higher than the well-recognized classic prognostic factors in node-negative breast cancer. The present data highlight the need to assess the prognostic value of potentially new biological factors in node-negative breast cancer on cohorts of patients followed over periods in excess of 10 years.

Application of an original RT-PCR-ELISA multiplex assay for MDR1 and MRP, along with p53 determination in node-positive breast cancer patients

The long-term prognostic value of tumoural MDR1 and MRP, along with p53 and other classical parameters, was analysed on 85 node-positive breast cancer patients receiving anthracycline-based adjuvant therapy. All patients underwent tumour resection plus irradiation and adjuvant chemotherapy (the majority receiving fluorouracil-epirubicin-cyclophosphamide). Median follow-up for the 54 alive patients was 7.8 years. Mean age was 53.7 years (range 28-79) and 54 patients were post-menopausal. MDR1 and MRP expression were quantified according to an original reverse transcription polymerase chain reaction multiplex assay with colourimetric enzyme-linked immunosorbent assay detection (beta2-microglobulin as control). P53 protein was analysed using an immunoluminometric assay (Sangtec). MDR1 expression varied within an 11-fold range (mean 94, median 83), MRP within a 45-fold range (mean 315, median 242) and p53 protein from the limit of detection (0.002 ng mg(-1)) up to 35.71 ng mg(-1) (mean 1.18, median 0.13 ng mg(-1)). P53 protein was significantly higher in oestrogen receptor (ER)-negative than in ER-positive tumours (P = 0.039). The higher the p53, the lower the MDR1 expression (P = 0.015, r= -0.27). P53 was not linked to progesterone receptor (PR) status, S phase fraction, or MRP Significantly greater MDR1 expression was observed in grade I tumours (P = 0.029). No relationship was observed between MDR1 and MRP. Neither MDR1 nor MRP was linked to ER or PR status. Unlike MDR1, MRP was correlated with the S phase: the greater the MRP, the lower the S phase (P = 0.006, r = -0.42). Univariate Cox analyses revealed that MDR1, MRP, p53 and S phase had no significant influence on progression-free or specific survival. A tendency suggested that the greater the p53, the shorter the progression-free survival (P = 0.076 as continuous and 0.069 as dichotomous).

[Immunohistochemical evaluation of the in vitro bromodeoxyuridine labeling index. 236 breast cancers studies by image analysis]

We studied with computerized image analysis 236 breast cancer samplings after in vitro bromodeoxyuridine incorporation and immunohistochemical revelation. Labeling index values were compared with the usual prognostic factors and with the other studies in the literature. We established a positive correlation between labeling index and tumor size, histoprognostic grading, phase S and DNA index. A high labeling index was correlated with the absence of hormonal receptors but not correlated with the other prognostic factors. These results on tumor kinetics are similar to those obtained by flow cytometry and from other studies in the literature. However, this technic using optical microscopy allows for reliable selection of tumoral cells. Furthermore, the semi-automated image analysis provides an objective and reproducible evaluation of the labeling index.

A multifactorial approach including tumoural epidermal growth factor receptor, p53, thymidylate synthase and dihydropyrimidine dehydrogenase to predict treatment outcome in head and neck cancer patients receiving 5-fluorouracil

The prognostic value of tumoural epidermal growth factor receptor (EGFR), p53, thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) was analysed on 82 advanced head and neck cancer patients (71 men, 11 women; mean age 59). Induction treatment was cisplatin-5-FU +/- folinic acid (61 patients, Chem group) or concomitant cisplatin-5-FU-radiotherapy (21 patients, RChem group). EGFR (binding assay), p53 protein (Sangtec immunoluminometric assay), TS and DPD activities (radioenzymatic assays) were measured on biopsies obtained at time of diagnosis. Significant positive correlation was demonstrated between p53 and EGFR. In the RChem group, p53 was higher in non-complete responders (median 1.03 ng mg(-1)) than in complete responders (median 0.08 ng mg(-1)) (P = 0.057). Univariate Cox analyses stratified on treatment group showed that specific survival (33 events) was significantly related to T staging, p53 taken as continuous or categorial (below vs over 0.80 ng mg(-1)) variable, and EGFR (below vs over 220 fmol mg(-1)); survival increased when EGFR and p53 were below thresholds. Multivariate stepwise analysis including T staging, EGFR and p53 revealed that T staging and EGFR were independent predictors of survival; relative risks were 3.68 for T staging and 2.65 for EGFR. Overall, EGFR remained an independent prognostic factor when response to treatment and T staging were considered in the multivariate analysis.

Combination of irinotecan (CPT11) and 5-fluorouracil with an analysis of cellular determinants of drug activity

We evaluated the combination SN38 (7-ethyl-10-hydroxycamptothecin) -5fluorouracil (5FU) +/- folinic acid (FA) on six human colon cancer cell lines expressing spontaneous sensitivity to both drugs. Tumoral parameters potentially related to drug sensitivity were investigated: topoisomerase I (topo I) cleavable complexes formed with SN38, thymidylate synthase (TS) activity, folylpolyglutamate synthetase activity and dihydropyrimidine dehydrogenase activity. Drugs (SN38 and/or 5FU +/- FA) were applied for 72 hr, either sequentially or together. The concentration ratio between SN38 and 5FU was 100. Cytotoxicity (MTT [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide] test), DNA flow cytometry and isobologram analysis (Chou and Talatay) were performed. Based on 5FU IC50 values and isobologram analyses, the most cytotoxic schedule was SN38 followed by 5FU - FA, with high synergistic effects. Flow cytometry indicated that SN38 induced a more or less marked S-G2 block in all cell lines. Sensitivity to SN38, 5FU +/- FA, or combinations were not linked to the potential above-cited tumoral parameters. Interestingly, an inverse correlation was demonstrated between TS activity and topo I cleavable complexes (r2 = 0.78, P = 0.019). These data emphasize the critical importance of the irinotecan-5FU schedule and strongly support this association for the treatment of potentially 5FU-sensitive tumors.

Epidermal growth factor receptor and labeling index are independent prognostic factors in glial tumor outcome

The aim of this study was to perform a multivariate analysis including clinical and biological prognostic factors on glial tumor outcome. Seventy-nine patients were analyzed (48 men and 31 women; mean age = 56 years, range = 16-77 years): 7 had a benign glial tumor (grades 1 and 2), 21 had an anaplastic glial tumor (grade 3), and 51 had a glioblastoma (grade 4). Median follow-up was 17.9 months for patients who survived (50 patients died). Biopsies were obtained at time of diagnosis (complete tumor resection in 62 patients and stereotaxic biopsies in 17 patients). Epidermal growth factor receptor (EGFR) was measured by a binding assay, and labeling index (LI) was measured by tritiated thymidine incorporation. EGFR varied from 4 to 73,110 fmol/mg protein (mean = 3912 fmol/mg protein; median = 374 fmol/mg protein; n = 79). LI varied between 0.1 and 16.5% (mean = 6.2%; median = 5.2%; n = 40). Log10 EGFR was significantly and positively correlated with patient age. LI was significantly different according to tumor histology. Univariate Cox analysis (end point was cancer death) showed that age (P = 0.027), log10 EGFR (P = 0.025), and LI (P = 0.0019) were significant continuous variables, the survival being shortened when the covariable increased; tumor resection (P = 0.015, relative risk = 0.45) and histology (P = 0.0009) were significant categorical factors. A multivariate Cox analysis (forward selection) including age, histology, tumor resection, log10 EGFR, and LI revealed that log10 EGFR, LI, and tumor resection were the only independent significant predictors of survival. This multivariate approach reveals that the clinical prognostic factors of glial tumors, namely age and tumor histology, disappear, to the benefit of intrinsic characteristics of the tumor, i.e., EGFR expression and LI, suggesting that coupled EGFR and LI determination could be a useful tool for better evaluation of glial tumor outcome.

Comparison between short or long exposure to 5-fluorouracil in human gastric and colon cancer cell lines: biochemical mechanism of resistance

Recent preclinical and clinical data indicate that the main mechanisms of 5-fluorouracil (5-FU) cytotoxicity depend on the mode of administration. To gather further insight into the major causes of acquired 5-FU resistance, drug-sensitive human gastric (M2), colon (HT29) and breast (MCF7) cancer cell lines were repeatedly exposed to a fixed concentration of 5-FU given either for 1 or 24 h. Although equieffective doses (IC50) of 5-FU were used, resistance to a 1 h exposure of 5-FU developed faster in all models than to a 24 h exposure. Cell lines with acquired resistance to a 1 h application of 5-FU were only partly cross-resistant to a 24 h exposure, whereas lines with resistance to protracted application of 5-FU displayed significant cross-resistance to the 1 h schedule. Resistance to methotrexate was only seen in cell lines with acquired resistance to 24 h of 5-FU. All 5-FU-resistant cell lines showed reduced incorporation of 5-FU into cellular RNA. Furthermore, elevations of thymidylate synthase were seen in all cell lines with resistance to 24 h of 5-FU but also in one cell line with resistance to a bolus schedule. No alterations in folylpolyglutamate synthase developed in the resistant cell lines. These data support the concept that the main mechanisms of 5-FU cytotoxicity depend on the mode of application. Incorporation of fluorouridine triphosphate into RNA appears to be the most important mechanism of action for 5-FU bolus schedules, whereas inhibition of thymidylate synthase becomes more important as the infusion time is prolonged. These data could have implications on the interaction of 5-FU given at different schedules with various other cytostatic agents.

A clinically applicable assay for tumoral thymidylate synthase combining reverse transcriptase-PCR and high-performance liquid chromatography

The main clinically relevant cellular target of 5-fluorouracil (5-FU) is the enzyme thymidylate synthase (TS). Both preclinical data and clinical data in digestive tract cancer indicate that an increased amount of TS in tumours can predict for 5-FU resistance. We developed an automated method combining the principle of RT-PCR coupled with HPLC separation and quantification. The RT-PCR HPLC method was applied to TS determination in tumoral biopsies from patients with colorectal cancer. The PCR samples were separated and quantified using a polystyrene divinylbenzene C 18 column. Within 22 min, it was possible to elute 18 peaks representing DNA sizes ranging from 34 to 622 bp. Both separation and quantification of beta 2 microglobulin (beta 2m, internal standard) and TS PCR products were achieved in approximately 10 min per sample. Validation of the RT-PCR HPLC method was established by comparing RT-PCR quantification of TS after electrophoresis and HPLC and by comparing the RT-PCR quantification of TS after HPLC with the classical biochemical method. The proposed HPLC method offers a 10-50 fold sensitivity advantage over electrophoresis. In addition, this RT-PCR HPLC procedure allows not only the quantification of TS expression but also the direct collection of unaltered amplified DNA sequence which could be useful for sequencing analysis, since TS mutations have been described. The present RT-PCR HPLC method for determining TS expression in tumoral biopsies is a valuable analytical approach as it is specific, sensitive and clinically applicable.

Decreased folylpolyglutamate synthetase activity in tumors resistant to fluorouracil-folinic acid treatment: clinical data

Thymidylate synthase (TS) is the main target for fluorouracil (FU). Optimal cellular concentrations of reduced folates in polyglutamated forms [via folylpolyglutamate synthetase (FPGS)] are necessary for achieving maximal TS inhibition. The aim of this multicentric prospective study was to analyze the link between clinical response to FU therapy for liver metastases of colorectal carcinoma and tumoral TS and FPGS activities. Forty-four advanced colorectal cancer patients (15 women and 29 men; median age 63, range, 27-78 years) receiving a standard FU-folinic acid protocol were included. A single hepatic tumoral biopsy was obtained systematically at the time of diagnosis. For 24 patients, a biopsy in the primary colon tumor was available. TS and FPGS activities were measured by radioenzymatic assays. Clinical response on hepatic metastases was 1 complete response, 12 partial responses, 14 stabilizations, and 17 progressions. In hepatic biopsies, TS activity (median, 185; range, <10-3111 fmol/min/mg protein) and FPGS activity (median, 1270; range, <400-3730 fmol/min/mg protein) exhibited a wide variability. TS activity in primary tumors (median, 461; range, 35-2565 fmol/min/mg protein) was significantly higher than in hepatic metastases. No difference was observed between primaries and metastases for FPGS. FPGS activity expressed in liver metastases was significantly correlated to that expressed in primaries. The distribution of TS activity in liver metastases was not significantly different between responsive and nonresponsive patients. However, FPGS activity measured in liver metastases was significantly higher in responsive patients (median, 1550 fmol/min/mg protein) than in nonresponsive patients (median, 1100 fmol/min/mg protein). A discriminant analysis revealed that 24 of the 25 patients exhibiting a liver FPGS activity </=1100 fmol/min/mg protein and/or a liver TS >320 fmol/min/mg protein were nonresponding patients. These data establish for the first time the potential importance of tumoral FPGS activity for assessing FU-folinic acid responsiveness in the clinical setting.

Improvement of quality control for steroid receptor measurements: analysis of distributions in more than 40000 primary breast cancers. French Study Group on Tissue and Molecular Biopathology

All French laboratories that routinely assay estradiol (ER) and progesterone (PR) receptors participate in the European EORTC quality control program based on twice-yearly analysis of 5 cytosolic preparations. This system has considerably reduced inter-laboratory variations, but does not cover all aspects of these assays. Analysis of receptor value distributions is also crucial to ensure that receptor measurements remain stable with time, independently of the laboratory and assay method. This study involved 83907 receptor assays carried out in the last 17 years by 17 laboratories belonging to the French Study Group on Tissue and Molecular Biopathology. The assays were based on radioligand binding (RLA) or immunoenzymology (EIA). For each laboratory, the medians and positivity rates were analysed according to two totally objective criteria, the patient's age and the year of assay, and according to histological grade and histological type of the tumor in order to verify the correlations classically described. Age-related distributions varied little between laboratories, compared with data published by 7 European EORTC laboratories [1]. The results remained relatively stable with time in the RLA method for ER and PR, and in the EIA method for PR. Median ER-EIA data showed a marked increase between 1987 and 1989, mainly due to changes in the quality of Abbott reagents during this period. Otherwise, this analysis confirms previous pathophysiological observations.

[EGF receptor, a prognostic factor in epidermoid cancers of the upper aerodigestive tracts]

EGFR was determined, before treatment; in tumors biopsies obtained from 109 consecutive patients with head and neck cancer (100 men and nine women), using iodine labelled recombinant EGF. The median age of the study population was 60 years. EGFR levels varied from 2 to 2302 fmol/mg membrane protein (median 71). There was a significant difference of distribution for EGFR levels between stages I and II tumors and stages III and IV tumors (P = 0.03). The EGFR cut-off value for overall survival was 120 fmol/mg protein and the median follow-up was 18 months (3-35) EGFR overexpression was associated with shorter relapse-free (P = 0.0125) and overall survival (P = 0.028). By multivariate analysis the only significant variables were EGFR for relapse-free survival and tumor staging and EGFR for overall survival. Analyzed in 60 patients treated by first-line chemotherapy CDDP-5FU, the longest survival was achieved for patients who had a complete response to chemotherapy and the lowest EGFR levels (P = 0.018). EGFR expression in the primary tumor allows survival among first line chemotherapy responder categories to be discriminated.

Determination of oestrogen receptors by enzyme immunoassay. Technical differences between laboratories and their consequences

When multicentre breast cancer trials are performed, receptor analyses must be comparable both over time and in the participating laboratories. However, we show for the first time a high variability for the distribution of oestradiol receptor (ER) values measured by enzyme immunoassay (EIA) from 1987 to 1991. This variability could be explained by calibration changes in the immunoassay kits. We have also analysed the influence on ER-EIA levels of technical differences between laboratories apart from the assay itself. Many steps emerged as being critical, i.e. homogenisation buffer, homogenisation procedure and cytosol dilution. Finally, we show that addition of 4-monohydroxytamoxifen increases the apparent ER content measured by EIA in 92% of cytosols. Thus, many factors must be controlled to ensure high precision with ER-EIA assays. We have to be particularly cautious with the conformational changes that could occur during cytosol preparation and that could also pre-exist in the tumour samples. Quality controls of cytosol preparation are essential.

Expression of epidermal growth factor receptor and survival in upper aerodigestive tract cancer

PURPOSE

To determine the expression of epidermal growth factor receptor (EGFR) in head and neck squamous cell carcinoma and to evaluate its prognostic value.

MATERIALS AND METHODS

EGFR was determined in tumor biopsies obtained from 109 consecutive patients with head and neck cancer (100 men, nine women). Control biopsies were obtained from 94 patients in a symetric nontumoral area of the same anatomic site. EGFR was measured by a binding assay using human recombinant iodine 125-EGF.

RESULTS

The presence of detectable EGFR levels was found in all explored tumors with highly marked differences between patients (median, 71 fmol/mg protein; range, 2 to 2,302). In 93 of 94 cases, EGFR levels were higher in tumor samples as compared with healthy control zones. There was no significant difference in EGFR expression according to the various anatomic sites explored or tumoral differentiation status. There was a significant difference of distribution for EGFR levels between stages I and II tumors and stages III and IV tumors. The tumor EGFR levels were not linked to the response to first-line chemotherapy by cisplatin (CDDP) and fluorouracil (5FU). Survival was assessable for 103 patients for overall survival and for 81 patients for recurrence. EGFR overexpression was associated with shorter relapse-free (P = .0125) and overall survival (P = .028) rates. By multivariate analysis, the only significant variable was EGFR for relapse-free survival and tumor staging for overall survival. The association of EGFR to tumor staging markedly improves the significance for overall survival predictability (P = .002).

CONCLUSION

EGFR determination deserves particular attention in head and neck cancer, since it independently carries a strong prognostic value.

[Demonstration and characterization of EGF receptors in cancer of the uterine cervix]

Epidermal Growth Factor in a polypeptide growth factor of which receptor EGFR has a prognosis value for some malignant tumours. Data are limited concerning the EGFR value in cervix tumours. EGFR was measured in biopsies obtained in cervix cancer patients before any treatment. Twenty-two patients (18 squamous carcinomas, 4 adenocarcinomas) were studied. EGF binding was characterized in seven tumour samples. Scatchard representation identified a single family of binding sites. Kd value revealed high affinity for EGF binding: 0.645 +/- 0.769 nmol/l. EGFR values were determined by a simplified competition method using a radiolabeled ligand. EGFR was found to be more elevated in tumours (n = 20) than in normal tissue (n = 4): (59.5 vs 10.5 fmol/mg proteins). There was a tendency for higher EGFR values in squamous tumours (m = 83.5 fmol/mg proteins) as compared to adenocarcinomas (m = 35.5 fmol/mg proteins), P = 0.09. There was no difference in the distribution of EGFR values according to tumour differentiation and staging. This work confirms the presence of EGFR in cervix tumours. Interestingly, we found that tumours with high EGFR values were more radiosensitive than tumours with low values.

Characterization, quantification, and potential clinical value of the epidermal growth factor receptor in head and neck squamous cell carcinomas

Epidermal growth factor (EGF) stimulates the growth of several types of epithelial tissues and possesses a strong mitogenic activity that is mediated through its cell surface receptor (EGFR). The aim of this study was to characterize EGFR and measure its levels in head and neck tumors biopsies (70 patients); use of a simplified competition technique with a radiolabeled ligand allowed evaluation of functional EGFR. Five samples (4 tumors and 1 control) were used to characterize EGF binding. Graphic representation identified a single family of binding sites. Kd values revealed high affinity for EGF binding: mean Kd, 0.156 +/- 0.108 nM (0.095-0.347 nM). EGF-binding characteristics (Kd) were similar in nontumoral tissue samples (controls) and in tumor material. In 59 of 60 cases, EGFR levels were higher in the tumor than in the corresponding controls. A significant correlation was found between EGFR levels and tumor size and stage. Controls exhibited a trend toward higher EGFR levels in elevated sizes and stages. According to a cutoff EGFR value of 100 fmol/mg protein, which separated all controls from tumors, EGFR-positive tumors (greater than 100 fmol/mg protein) had a greater probability of complete response to chemotherapy than EGFR-negative tumors; other tumor characteristics, such as the degree of tumoral differentiation, tumor size, or stage, were unable to operate such a discrimination in the response to chemotherapy. EGFR may thus be an interesting biological marker for head and neck cancer.

Epidermal growth factor receptor assay: validation of a single point method and application to breast cancer

Epidermal growth factor (EGF) is a 6000 kDa peptide which exerts its biological effects by binding to a specific cell membrane receptor (EGF-R). Extensive studies on EGF-R in breast tumors have demonstrated the prognostic value of such assays. EGF-R measurement is also reportedly potentially useful in other tumors. Classically, the EGF-R content of tumor cell membrane preparations is evaluated by competition between a given concentration of labeled ligand and various concentrations of unlabeled ligand. The large quantity of tumor tissue required (approx. 0.5 g) is a serious limitation for wide-spread use of EGF-R assays. In order to validate a miniaturized EGF-R assay method, the principle of a single-dose technique (SD) using a single concentration of labeled ligand (1 nM) was investigated in the present work. Only 100-150 mg wet tissue were required for routine analysis by the SD method. The correlation between the SD method and Scatchard analysis calculated from 41 different breast carcinoma samples was very satisfactory (r = 0.973, p less than 0.001). Analysis of intra-assay and inter-assay reproducibility revealed a comparable EGF-R status in given samples. The correlation between EGF-R levels and steroid receptors was investigated in 105 individual breast tumors. EGF-R levels were inversely correlated with the estradiol receptor values. No correlation was found with progesterone receptors. The simplified SD method for EGF-R measurement appears suitable for large scale clinical studies aimed at investigating the potential utility of this biological tumor marker.

Oestrogen and progesterone receptor status in bone biopsy specimens from patients with breast cancer

Of 16 breast cancer patients with histologically proven, tumour-infiltrating biopsy specimens most had low ER and PR values; the ER and PR contents varied between 0 and 135 and 0 and 44 fmol/mg protein, respectively. With the conventional clinical threshold of 10 fmol/mg protein, 8 specimens (50%) were ER-PR-, 4 (25%) ER-PR+, 3 (19%) ER+PR+ and 1 (6%) ER+PR-. ER levels were significantly lower in the tumoral bone lesion compared with the primary tumour. For 15 patients with negative biopsies and without endocrine treatment, ER and PR concentrations were quantifiable (2 fmol/mg protein or more) in 9 (60%) and 11 cases (73%), respectively. 8 of 9 patients over 55 (89%) were ER+ (2 fmol/mg protein or more). Conversely, for patients under 55, 1 of 6 (17%) was ER+ (P less than 0.001). Results for PR were similar. These data strongly suggest that steroid receptors are present in healthy bone tissue.

Steroid receptors in human osteoblast-like cells

The presence and functions of steroid receptors were evaluated in three human osteosarcoma cell lines (OS1 = SA OS; OS2 = HOS TE 85, and OS3 = MNNG HOS TE 85). The human breast cancer cell line MCF-7 was used as internal control for oestrogen receptors (E2R). High and low affinity sites were characterised. The high affinity sites had a similar dissociation constant in all four cell lines. In contrast, the number of sites per cell was higher in MCF-7 cells. E2 did not significantly modify the number of progesterone receptors (PgR) per cell in any of the osteosarcoma lines. As expected, E2 increased the number of PgR sites per MCF-7 cell. 4-hydroxytamoxifen decreased the growth of MCF-7 cells only. OS1 and OS2 were sensitive only to the highest concentration tested, which produces only non-specific cytotoxic effects. Thus E2R and PgR were found in osteoblast-like cells, but the function of E2R in such cells remains unknown.

Tamoxifen metabolism: pharmacokinetic and in vitro study

The qualitative and quantitative importance of tamoxifen (TMX) metabolism in vivo led us to investigate further the metabolic profile of this major anti-oestrogenic drug in a significant group of 81 breast cancer patients and to evaluate the respective in vitro activity of each metabolite. TMX and its four metabolites described until now (NDT, 4-OHT, Y, Z) were measured in blood (HPLC method) at the time of first drug intake and at the steady state. Between these two states, the unchanged drug relative proportion dropped from 65% to 27%. Demethylation was the major metabolic pathway. For 13 clinically evaluable patients, there was no significant difference in the distribution of serum levels of TMX and metabolites as a function of response to treatment. In vitro studies were performed on two human breast cancer cell lines: MCF-7, oestrogen receptor and progesterone receptor positive (ER+, PR+) and CAL-18 B (ER-, PR-). Cytostatic effects were evaluated by the tritiated thymidine incorporation test. TMX and all metabolites were active on these two cell lines, but the 50% inhibitory concentrations (IC50) were 4-250-fold higher in CAL-18 B than in MCF-7, depending on the metabolite considered. For the MCF-7 cells only, the antiproliferating activity was parallel to the relative binding affinity for ER. Moreover, for the MCF-7 cells only, the effects of these drugs were partially reversed by oestradiol (E2), the higher the metabolite affinity for ER, the lower the reversal efficacy. These compounds were tested in mixtures at proportions duplicating those found in patients after initial drug intake (mixture D1), and the steady state (mixture Css). The mixtures were also compared to the equimolar unchanged drug. No differences were seen among these three experimental conditions for either MCF-7 or CAL-18 B. A dose-effect relationship was noted. Overall, TMX and its metabolites exert a dual effect: when concentrations are below a threshold between 2 x 10(-6) and 10(-5) M, the drugs are mainly cytostatic; this effect is related to their affinity for ER. At higher relevant clinical concentrations, a cytotoxic activity is observed and it appears independent of the presence of ER.

HPLC micromethod for simultaneous measurement of estradiol, progesterone, androgen and glucocorticoid receptor levels. Application to breast cancer biopsies

Estradiol (ER), progesterone (PR), androgen (AR) and glucocorticoid receptor (GR) levels were assayed in 25 breast cancer tumors. The tissue was pulverized and homogenized in buffer, then divided into two parts: one was assayed by the standard dextran-coated charcoal method (DCC), with Scatchard plot analysis, the other was assayed by a micromethod developed in our laboratory, as described below: --incubation of the cytosol with several ligands (labelled and unlabelled) selected to avoid unwanted cross-reactions --DCC separation, followed by extraction of all receptor-bound steroids by precipitation of proteins with methanol/TCA --separation of these steroids on a high pressure liquid chromatography (HPLC) column using a methanol/water solvent --collection of the fractions of the column outlet and counting. Use of three labelled ligands and appropriate unlabelled ligands allowed assays of the four receptors. This micromethod was highly correlated with the standard method: ER = 0.985 (P less than 0.001); PR = 0.999 (P greater than 0.001); AR = 0.989 (P less than 0.001); GR = 0.867 (P less than 0.001). Thresholds of positivity were not modified. This micromethod allowed simultaneous measurement of several receptors in 40 mg biopsy specimens and can be applied to other hormone-dependent tissues.

Optimised analysis of tamoxifen and its main metabolites in the plasma and cytosol of mammary tumours

Recent biochemical and pharmacological findings concerning tamoxifen (TMX) have proven that both the unchanged drug and the main metabolites, N-desmethyltamoxifen (NDT) and 4-hydroxytamoxifen (4OHT) are biologically active. An HPLC method based on on-line post-column UV irradiation with fluorescence detection is described. Optimized conditions allowed complete and rapid separation of TMX 4OHT, NDT and two other recently reported metabolites, Y and Z. This method was applied to plasma and cytosol drug and metabolite analyses. In plasma, from the moment of initial drug administration until the steady state (after 1 month or more of continuous oral TMX treatment), the values of NDT to TMX ratios were completely reversed: 22 to 215 in mean %, P less than 0.01. The presence of metabolites Y and Z is significant. 4OHT, hardly detectable at the first dose, was measured at the steady state with high interpatient variability. It is hypothesized that metabolite evolution with time may be due to auto-induction of drug metabolism. In cytosols, which were all obtained during continuous TMX treatment, the ratios between TMX and metabolites were comparable to those observed in plasma, but with greater interpatient variability. Metabolite Y was not detectable in cytosols. This variability was not linked to the levels of cytosolic oestradiol receptors before initiation of treatment.

Simultaneous micro measurement of steroid receptors in breast cancer

The oestradiol (RE) and progesterone (RP) receptor levels were analyzed in 26 tumour fragments (200-500 mg) from breast cancer patients. After pulverization of tissue, one part was analyzed by the routine dextran-coated charcoal (DCC) method and the other by a micromethod as follows: (i) cytosol incubation using the DCC method but in the simultaneous presence of [3H]oestradiol and [3H]R5020 (ii) extraction of the steroids bound to the receptor by precipitation with ethanol/TCA (iii) high pressure liquid chromatography (HPLC) on a modular system, with a C185 microns column and an elution by gradient mixture methanol/water. The fractions were collected and the radioactivity counted. The separation of oestradiol from R 5020 was rapid and complete. In addition dexamethasone was separated by this system making possible triple measures of RE, RP and glucocorticoid receptors. A highly significant correlation was obtained between the 2 methods: RE = 0.996, P less than 0.001; RP r = 0.975, P less than 0.001, implying that the thresholds of positivity, i.e. for therapeutic decisions, remain unchanged. Simultaneous measurement of RE and RP in a single needle biopsy is possible with this micromethod.

Thyroid activity during hepatocarcinogenesis by N-2-fluorenylacetamide in the male rat

During chemical hepatocarcinogenesis by N-2-fluorenylacetamide, the hormonal status of male Sprague Dawley rats is modified. The histological study of the thyroid gland demonstrates a decreased activity evidenced by an augmentation of the follicle size and a reduced size of follicular epithelium. The level of T3 and T4 reflects in part this decreased activity. Comparison with female rats treated in the same conditions shows an opposite effect of N-2-fluorenylacetamide. Indeed in the female, the thyroid gland presented an hyperactive state accompanied by a drastic decrease of serum T3 and T4. This difference in thyroid activity might take an important part in the mechanism responsible for the sex difference in liver cancer induction by N-2-fluorenylacetamide.

Thyroid activity during hepatocarcinogenesis by N-2-fluorenylacetamide

During chemical carcinogenesis by N-2-fluorenylacetamide, the hormonal status of female Sprague Dawley rats is largely modified. Thyroids present a modified activity which is evidenced by the histological study as well as T4 and T3 assays. In hypophysis, thyrotropic cells were found in an hyperactive state, a fact which is in agreement with the changes observed in thyroid follicles size and epithelial cells demonstrating an hyperactivity of thyroid glands. Despite this histological result, T4 serum level was lowered. T3 level was also decreased but to a lesser extent. We suggest that the low thyroid hormone level play a role in the relative protection of females versus males toward liver cancer induction by chemicals.