Hiroshi Sonoo

Clinicopathologic Characteristics and Prognosis of Breast Cancer Patients Associated with Pregnancy and Lactation: Analysis of Case-Control Study in Japan

Clinicopathologic characteristics and prognosis of breast cancer patients associated with pregnancy and lactation were clarified by means of a case‐control study of matched non‐pregnant and non‐lactating patients with breast cancer. From 18 institutions in Japan, a total of 192 subjects with breast cancer diagnosed during pregnancy (72 cases) and lactation (120 cases) were collected between 1970 and 1988, accounting for 0.76% of all breast cancer patients. The duration of symptoms was longer and tumor size was larger in the study subjects. Although the disease‐free interval was longer than that in the control patients, the survival time was shorter. There was no characteristic difference in histologic type. Vascular invasion and lymph node metastasis were found more frequently in the subjects. The positive rates of estrogen receptor and progesterone receptor were lower in the subjects. The 5‐ and 10‐year survival rates of the study patients were 65% and 55%, respectively, and these survivals were significantly lower than those of the control (P < 0.001). The survival rates were poorer in the subjects, in accordance with stage and lymph node metastasis. The results suggest that most of the patients with breast cancer diagnosed during pregnancy and lactation are in a more advanced stage because of a delay in detection and diagnosis, and hence have unfavorable prognosis. Therefore, it is important to diagnose and treat early for improvement of prognosis in patients with breast cancer during pregnancy and lactation.

Expression of vascular endothelial growth factor (VEGF) family members in breast cancer

Vascular endothelial growth factor (VEGF)‐A is known to play an important role in tumor angiogenesis. Three additional members of the VEGF family, VEGF‐B, ‐C and ‐D, have recently been discovered. VEGF‐C and VEGF‐D are ligands for VEGF receptor‐3, which is expressed in the endothelium of lymphatic vessels. The expression of VEGF‐C is known to be associated with the development of lymphatic vessels. Therefore, it is conceivable that VEGF‐C and VEGF‐D might play a role in the development of lymphatic vessels in solid tumors. To obtain some clue as to this role, we developed a semi‐quantitative reverse transcription‐polymerase chain reaction method to investigate the mRNA expression levels of each VEGF family member in breast cancer. All the VEGF family members were expressed at different levels in seven human breast cancer cell lines explored. Although VEGF‐A and VEGF‐B expressions were detected in both node‐positive and node‐negative breast tumors, VEGF‐C expression was detected only in node‐positive tumors. VEGF‐D expression was detected only in an inflammatory breast cancer and a tumor which developed an inflammatory skin metastasis. These findings suggest a possible relationship between the expression level of VEGF‐C and/or VEGF‐D and the development of lymphatic tumor spread.

Oral Uracil and Tegafur Compared With Classic Cyclophosphamide, Methotrexate, Fluorouracil As Postoperative Chemotherapy in Patients With Node-Negative, High-Risk Breast Cancer: National Surgical Adjuvant Study for Breast Cancer 01 Trial

PURPOSE The primary aim of this study was to compare the effectiveness of oral uracil-tegafur (UFT) with that of classical cyclophosphamide, methotrexate, and fluorouracil (CMF) given as postoperative adjuvant treatment to women with node-negative, high-risk breast cancer. PATIENTS AND METHODS Women with node-negative, high-risk breast cancer were randomly assigned to receive either 2 years of UFT or six cycles of CMF after surgery. The primary end point was relapse-free survival (RFS). Overall survival (OS), toxicity, and quality of life (QOL) were secondary end points. The hypothesis was that UFT was not inferior to CMF in terms of RFS. RESULTS Between October 1996 and April 2001, a total of 733 patients were randomly assigned to receive either treatment. The median follow-up time was 6.2 years. The RFS rates at 5 years were 88.0% in the CMF arm and 87.8% in the UFT arm. OS rates were 96.0% and 96.2%, respectively. The hazard ratios of the UFT arm relative to the CMF arm were 0.98 for RFS (95% CI, 0.66 to 1.45; P = .92) and 0.81 for OS (95% CI, 0.44 to 1.48; P = .49). The toxicity profiles differed between the two groups. The QOL scores were better for patients given UFT than those given CMF. CONCLUSION RFS and OS with oral UFT were similar to those with classical CMF. Given the higher QOL scores, oral UFT is a promising alternative to CMF for postoperative adjuvant chemotherapy in women with node-negative, high-risk breast cancer.

Anti-HER2 antibody enhances the growth inhibitory effect of anti-oestrogen on breast cancer cells expressing both oestrogen receptors and HER2

Anti-oestrogen is effective for the treatment of oestrogen receptor (ER)-positive breast carcinomas, butmost of these tumours become resistant to anti-oestrogen. It has been suggested that anti-oestrogen therapy may induce a HER2signalling pathway in breast cancer cells and this may cause resistance to anti-oestrogen. Thus, it is conceivable that combinedtherapy with anti-oestrogen and anti-HER2 antibody might be more effective. In the present study, we investigated the effect ofcombined treatment with a humanized anti-HER2 monoclonal antibody, rhumAbHER2 (trastuzumab), and an anti-oestrogen, ICI 182,780, onthe cell growth of three human breast cancer cell lines which respectively express different levels of ER and HER2. The combinedtreatment enhanced the growth inhibitory effect on ML-20 cells, which express a high level of ER and a moderate level of HER2, butshowed no additive effect on either KPL-4 cells, which express no ER and a moderate level of HER2, or MDA-MB-231 cells, which express no ER and a low level of HER2. It is also suggested that both the antibody and anti-oestrogen induce a G1–S blockade and apoptosis. These findings indicate that combined treatment with anti-HER2 antibody and anti-oestrogen may be useful for thetreatment of patients with breast cancer expressing both ER and HER2.

Hypoxia reduces hormone responsiveness of human breast cancer cells

Resistance to hormonal therapy frequently occurs following successful treatment in breast cancer. The mechanism responsible for this acquired resistance is still unknown. It has been suggested that a hypoxic tumor microenvironment promotes malignant progression of cancer, i.e., hypoxia may promote estrogen‐independent growth (a more malignant phenotype) of breast cancer. To clarify this hypothesis, the effects of hypoxia on the growth responses to hormonal agents and the expression levels of estrogen receptor (ER)‐α and progesterone receptor (PgR) were investigated in two human breast cancer cell lines, ML‐20 and KPL‐1. The expression level of ER‐α was significantly decreased by hypoxia (1% O2) in a tune‐dependent manner in both cell lines. Hypoxia also significantly reduced the growth‐promoting effect of estradiol (E2) and the growth‐inhibitory effects of an antiestrogen, ICI 182 780, and a progestin, medroxyprogesterone acetate, in both cell lines. In addition, hypoxia markedly suppressed the induction of PgR mRNA and protein by E2 in both cell lines. To clarify further the effect of hypoxia on ER‐α expression, the expression levels of hypoxia‐inducible factor‐la (HIF‐lα), a marker of hypoxia and ER‐α were immunohistochemically examined in 36 breast cancer specimens. ER‐α expression (both its proportion and intensity) was significantly lower in nuclear HIF‐lα‐positive tumors than in negative tumors. These findings indicate that hypoxia down‐regulates ER‐α expression as well as ER‐α function in breast cancer cells. These processes may lead to an acquired resistance to hormonal therapy in breast cancer

A Radicicol Derivative, KF58333, Inhibits Expression of Hypoxia-inducible Factor-1α and Vascular Endothelial Growth Factor, Angiogenesis and Growth of Human Breast Cancer Xenografts

A novel oxime derivative of radicicol, KF58333, binds to the heat shock protein 90 (Hsp90) and destabilizes its associated signaling molecules. These effects play a critical role in the growth inhibition of tumor cells. To further investigate the effects of this agent, it was administered to two human breast cancer cell lines, KPL‐1 and KPL‐4, both in vitro and in vivo. KF58333 dose‐dependently inhibited the growth and vascular endothelial growth factor (VEGF) secretion, concomitantly with a decrease in VEGF mRNA expression, in each cell line. This agent also suppressed the increase of VEGF secretion and expression induced by hypoxia (1% O2). Intravenous injections of this agent into nude mice bearing either KPL‐1 or KPL‐4 xenografts significantly inhibited the tumor growth associated with a decrease in the Ki67 labeling index and microvascular area and an increase in apoptosis and the necrotic area. These findings indicate that the antitumor activity of this radicicol derivative may be partly mediated by decreasing VEGF secretion from tumor cells and inhibiting tumor angiogenesis. To explore the action mechanisms of the anti‐angiogenic effect, the expression level of hypoxia‐inducible factor (HIF)‐lα was investigated. KF58333 provided a significant decrease in the HTF‐lα protein expression under both normoxic and hypoxic conditions. In contrast, the mRNA expression of HIF‐lα was not decreased by this agent. It is suggested that the post‐transcriptional down‐regulation of HIF‐lα expression by this agent may result in a decrease of VEGF expression and tumor angiogenesis.

Immunohistochemical Analysis of Ki-67, p53, p21, and p27 in Benign and Malignant Apocrine Lesions of the Breast: Its Correlation to Histologic Findings in 43 Cases

We examined Ki-67, p53, p21, and p27 immunolocalization in 43 cases of apocrine lesions of the breast and correlated these findings with histologic parameters to understand their biologic significance. Twenty cases were benign, 1 case was borderline, and 22 cases were diagnosed as malignant, including 9 intraductal and 13 invasive apocrine carcinomas. Both the ratio of Ki-67–positive cases (17 of 21 [88.9%] versus 1 of 19 [5.3%]; P < .001) and the Ki-67 labeling index of positive cases examined (15.0% versus 2.7%; P < .005) were significantly higher in malignant than in benign apocrine lesions. None of the benign or borderline cases was immunohistochemically positive for p53, but 15 of 22 malignant cases (68.2%) demonstrated p53 (P < .001). In addition, the ratio of p53-positive cases was significantly higher in high nuclear grade cases (11 of 13 [84.6%]) than in intermediate nuclear grade cases (4 of 9 [44.4%]; P < .05). P53 immunoreactivity was also positively correlated with the nuclear grade of carcinoma cases examined in this study. Neither p21 nor p27 demonstrated any correlation with histologic parameters or findings of the apocrine lesions. Results of these studies suggest that Ki-67 and p53 may be good markers for differentiation between benign and malignant breast apocrine lesions.

Additive antitumour effect of the epidermal growth factor receptor tyrosine kinase inhibitor gefitinib (Iressa, ZD1839) and the antioestrogen fulvestrant (Faslodex, ICI 182,780) in breast cancer cells

A high expression level of epidermal growth factor receptor (EGFR)/HER1 has been suggested to lead to a shorter survival time and resistance to endocrine therapy in patients with breast cancer. To test the hypothesis that inhibition of the EGFR signalling pathway affects the antitumour effect of endocrine therapy, an EGFR tyrosine kinase inhibitor (EGFR-TKI), gefitinib, and an oestrogen receptor (ER) antagonist, fulvestrant, were administered to human breast cancer cells. A total of five human breast cancer cell lines were used. The effects of single or combined treatments with gefitinib and/or fulvestrant on cell growth, cell cycle progression and apoptosis were analysed. Changes in the expression levels of cyclin-dependent kinase inhibitors, p21 and p27, an antiapoptotic factor, Bcl-2, and a proapoptotic factor, Bax, were also investigated. All cell lines tested were sensitive to gefitinib (50% growth inhibitory concentration, 10–28.5 μM). Breast cancer cell lines with a high expression level of HER1 or HER2 were more sensitive to gefitinib than the others. Gefitinib induced a significant G1–S blockade in ER-positive KPL-3C cells. Gefitinib induced significant apoptosis in HER1-overexpressing MDA-MB-231 cells. Gefitinib additively increased the antitumour effect of fulvestrant in all three ER-positive cell lines in a medium supplemented with 17β-oestradiol. The combined treatment promoted cell cycle retardation in KPL-3C cells, which is associated with an upregulation of p21 by fulvestrant and gefitinib, respectively. Apoptosis was associated with downregulation of Bcl-2 by gefitinib in MDA-MB-231 cells. These results suggest an additive interaction between the EGFR-TKI gefitinib and the antioestrogen fulvestrant in ER-positive breast cancer cells.

A new human breast cancer cell line, KPL-1 secretes tumour-associated antigens and grows rapidly in female athymic nude mice.

We recently established a new human breast cell line, designated KPL-1, which was derived from the malignant effusion of a patient with breast cancer. This cell line is highly tumorigenic and grows rapidly in female nude mice. Cytogenetic analysis indicated its human origin and revealed a hypertriploid modal number of chromosomes. Electron microscopic examination suggested that the KPL-1 cells are of epithelial origin. Immunohistochemical studies revealed that the cells express cytokeratin, carcinoembryonic antigen and CA 15-3. They also possess a large number of oestrogen receptors but not progesterone receptors. Interestingly, KPL-1 cells seem to grow oestrogen independently in vitro. No amplification of c-erbB-2, c-myc, H-ras and N-ras genes was detected. KPL-1 cells secrete a large amount of tissue polypeptide antigen (TPA). Although the secretion of CA 15-3 seemed to be constant throughout all cell growth phases, TPA secretion increased during the exponential growth phase and decreased during the plateau phase. Serum TPA levels significantly correlated with the volume of KPL-1 tumours transplanted into nude mice. These data suggest that this KPL-1 cell line may be useful for studying oestrogen-independent growth and the kinetics of tumour-associated antigens in vivo as well as in vitro.

A new human breast cancer cell line, KPL-3C, secretes parathyroid hormone-related protein and produces tumours associated with microcalcifications in nude mice.

Parathyroid hormone-related protein (PTHrP) is the main cause of humoral hypercalcaemia of malignancy (HHM). We recently established a new human breast cancer cell line, designated KPL-3C, from the malignant effusion of a breast cancer patient with HHM. Morphological, cytogenetic and immunohistochemical analyses indicated that the cell line is derived from human breast cancer. The KPL-3C cells stably secrete immunoreactive PTHrP measured by a two-site immunoradiometric assay, possess both oestrogen and progesterone receptors and are tumorigenic in female nude mice. The addition of phorbol-12-myristate-13-acetate to the medium significantly increased PTHrP secretion from the cells. In contrast, hydrocortisone, medroxyprogesterone acetate and 22-oxacalcitriol decreased PTHrP secretion in a dose-dependent manner. Unexpectedly, a number of microcalcifications were observed in the transplanted tumours. Radiographical examination indicated that the microcalcifications in the tumours are very similar to those commonly observed in human breast cancer. These findings suggest that this KPL-3C cell line may be useful for studying the regulatory mechanisms of PTHrP secretion and the mechanisms that lead to the deposition of microcalcifications in breast cancer.