David T. Kiang

Gross cystic disease fluid protein-15 as a marker for breast cancer: Immunohistochemical analysis of 690 human neoplasms and comparison with alpha-lactalbumin

The identification of metastatic carcinoma of the breast may be difficult in the absence of a previous history of breast cancer. Various immunophenotypic markers have been introduced to aid in this process. A monoclonal antibody directed at a 15-kilodalton (kd) gross cystic disease fluid protein (GCDFP-15) was applied immunohistochemically to paraffin sections of 105 breast cancers and 585 nonmammary malignancies in order to assess its value in this context. In addition, GCDFP-15 was compared with another putative mammary epithelial marker, alpha-lactalbumin (ALA), with respect to sensitivity and specificity for a diagnosis of breast carcinoma. Overall, the rates of specificity and sensitivity and the predictive value of a positive result for GCDFP-15 were 95%, 74%, and 74%, respectively. Corresponding statistical parameters for ALA were 50%, 50%, and 23%. A consistent congruency between the reactivity patterns of primary and metastatic breast cancers was noted for GCDFP-15 but not for ALA. Besides mammary carcinomas, the major tumor types that expressed GCDFP-15 were carcinomas of the salivary glands, sweat glands, and prostate. Since the latter three types of lesions are unlikely to be diagnosed as metastatic breast cancer, statistical indices were recalculated after exclusion of these three tumor types. Following this exclusion, the adjusted rate of specificity of GCDFP-15 and the predictive value of a positive result for a diagnosis of metastatic carcinoma of the breast were each 99%. In contrast, predictive parameters for ALA were not altered. These results show that GCDFP-15 is a specific marker for breast cancer and is superior to ALA in this respect.

Familial pyrimidinemia and pyrimidinuria associated with severe fluorouracil toxicity.

RAPIDLY growing tumor cells depend on a high rate of pyrimidine synthesis for the generation of RNA and DNA. Fluorouracil is a pyrimidine-base analogue that acts as an antimetabolite to block the s...

Down-regulation of type I insulin-like growth factor receptor increases sensitivity of breast cancer cells to insulin.

The type I insulin-like growth factor receptor (IGF1R) and insulin receptor (IR) are structurally and functionally related heterotetrameric receptors. Activation of IGF1R has been shown to regulate breast cancer cell biology, and it has become an attractive therapeutic target. Most strategies have focused on targeting IGF1R alone without affecting IR levels given the known physiologic functions of IR. Human breast cancer cell lines and tissues revealed mRNA expression of both IGF1R and IR. Because alphabeta chains of IGF1R and IR form hybrid receptors, we hypothesized that agents solely targeting IGF1R may affect tumor biology mediated by IGF1R/IR hybrids and IR. We used small interfering RNA (siRNA) technology to specifically down-regulate IGF1R by 60% to 80% in the MDA-435/LCC6 cell line, which was sufficient to diminish activation of IGF1R by IGF-I. IGF1R down-regulation by siRNA did not affect IR levels but, interestingly, sensitized cells to insulin activation of downstream signaling pathways in several breast cancer cell lines. IGF1R siRNA treatment diminished hybrid receptor formation, suggesting that specific down-regulation of IGF1R resulted in enhanced holo-IR formation. In addition, IGF1R down-regulation increased insulin binding consistent with the formation of an increased number of holo-IR on the cell surface. Accordingly, insulin-stimulated glucose uptake was enhanced on IGF1R down-regulation. In conclusion, our data suggest that specific siRNA targeting of IGF1R alone in breast cancer increases insulin sensitivity. Because IR also activates signaling pathways similar to IGF1R in breast cancer cells, agents targeting both receptors may be necessary to disrupt the malignant phenotype regulated by this growth factor system.

Factors affecting estrogen receptors in breast cancer

Estrogen receptor contents (ER), determined by a sucrose gradient method in 250 primary or metastatic breast cancers, were analyzed with respect to the influence of the patients menopausal status, chemotherapy, and tissue sampling. The incidence of the presence of estrogen receptors (ER+) increased in the order of para‐, pre‐ and postmenopausal status of the patient, suggesting that a tumor occurring at the paramenopausal phase tends to be a hormoneindependent type. Chemotherapy did not alter the incidence of ER(+), nor the quantity of ER in metastatic lesions. Multiple biopsies done simultaneously or sequentially in the same patient are consistent in their qualities and quantities of ER, provided histologic confirmation and examination of the amount of cellularity are included in the process of interpretation.

Tumor marker kinetics in the monitoring of breast cancer

Controversy exists in using carcinoembryonic antigen (CEA) for monitoring the clinical course of breast cancer. In this study, the kinetics of two plasma tumor markers, CEA and CA15‐3, immediately after the initiation of chemotherapy were assessed in 30 patients with advanced breast cancer. Four distinct kinetic patterns were seen. Two patterns fitted the expected relationship where the plasma marker increased during tumor progression (nine patients), and declined in tumor regression (five patients). The third pattern was paradoxical in that objective tumor regression in eight patients was associated with an acute surge of these markers followed by a steady decline. The doubling times for both CEA and CA15‐3 were immediately shortened four‐fold after therapy suggesting tumor cytolysis in treatment responders. Equally paradoxical was the fourth pattern where tumor progression in eight patients was associated with a rapid and transient decline of markers followed by rebounds. Such a rapid decline may be due to a suppression of marker release, as demonstrated in an in vitro study. Adequate knowledge of these putative paradoxical patterns will permit their effective use in monitoring the disease course and perhaps in the early prediction of the therapeutic response.

Immunoassayable insulin in carcinoma of the cervix associated with hypoglycemia

Immunoassayable insulin was elevated in the plasma and in the primary and metastatic lesions of a patient with carcinoma of the cervix. The release of insulin from the tumor tissue could have been the important factor in precipitating acute episodes of hypoglycemia in this patient.

Combination versus successive single agent chemotherapy in lymphocytic lymphoma.

Fifty‐three patients with advanced lymphocytic lymphoma were randomly assigned to treatment with the combination cyclophosphamide, vincristine, and prednisone (CVP) or the same agents used successively in maximal doses (C‐V‐P). Complete remissions occurred in 68% with CVP and 48% with C‐V‐P. For patients with nodular lymphoma, the complete remission rate was 81% with CVP and 46% with C‐V‐P. In patients with diffuse lymphoma a complete remission rate of 50% was obtained with both regimens. The median duration of response was longer for patients who obtained complete remission with CVP (37+ months) than for those entering remission with C‐V‐P (25+ months). More patients treated with CVP still survive. Current results suggest that CVP is a better induction regime than C‐V‐P in patients with nodular lymphoma. However, in patients with diffuse lymphocytic lymphoma, neither regimen results in more than 50% complete remissions or significant numbers of prolonged responses. More effective therapy is needed.

A Randomized Trial of Chemotherapy and Hormonal Therapy in Advanced Breast Cancer

We randomized 81 postmenopausal women with advanced breast cancer, whose tumors were rich in estrogen receptors or of unknown estrogen-receptor status, to receive either estrogen therapy alone or estrogen therapy combined with chemotherapy. An additional 31 patients, whose tumors were poor in estrogen receptors, were randomized to receive either chemotherapy alone or estrogen combined with chemotherapy. The median duration of follow-up was 87 months. In the receptor-rich group, the survival of the 21 patients receiving combined therapy was significantly longer than that of 19 patients receiving estrogen as initial therapy (followed by chemotherapy after failure or relapse). The median survivals were 72 and 29 months, respectively (P = 0.05 by the generalized Wilcoxon method). Among 41 patients with tumors of unknown receptor status, a survival advantage from combined therapy over chemotherapy was seen in the first two years and then disappeared. The survival in 31 patients with receptor-poor tumors was uniformly short regardless of the therapeutic method. We conclude that combined therapy offers a survival advantage in postmenopausal patients with receptor-rich tumors.

Additive growth-inhibitory effects of DL-α-difluoromethylornithine and antiestrogens on MCF-7 breast cancer cell line

We studied the growth inhibitory effects of DL-alpha-difluoromethylornithine, and antiestrogens (tamoxifen, 4-hydroxytamoxifen, trioxifene, keoxifene, and LY117018) as single agents and in combinations on the proliferation of a breast cancer cell line, MCF-7. At 0.1 mM difluoromethylornithine, the proliferation of MCF-7 cells was inhibited to 75 +/- 6% of the controls. Treatment of the cells with 0.1 microM 4-hydroxytamoxifen reduced cell growth to 72 +/- 4%. Combination of 0.1 mM difluoromethylornithine and 0.1 microM 4-hydroxytamoxifen reduced cell growth to 38 +/- 5%, indicating additive growth inhibitory effects. Similar additive effects were observed with all 5 antiestrogens in combination with difluoromethylornithine.

Estrogen receptor status and response to chemotherapy in advanced breast cancer

Tumor estrogen receptor status in women with advanced breast cancer was correlated with clinical response to cytotoxic chemotherapy in a retrospective study. Following an extramural review of the clinical data of 40 patients, 26 responded to chemotherapy (65%). The response rate in 19 receptor‐rich tumors was 89% and in 21 receptor‐poor tumors, 43% (P < 0.01). The lowest response rate (14%) was observed in seven postmenopausal patients with receptor‐poor tumors. Clinical characteristics of patients and variants in chemotherapy programs failed to explain the favorable response of receptor‐rich tumors to cytotoxic chemotherapy.