Eijiro Wakasugi

Midkine expression in human breast cancers : Expression of truncated form

The expression of midkine (MK), a growth/differentiation factor,was assessed in 34 surgically resected specimens ofprimary breast cancer or mastopathy. Using reverse transcriptase-polymerasechain reaction (RT-PCR) analysis, all of the non-cancerousand cancerous tissues were found to express MKexcept for one breast cancer specimen. Northern blotanalysis revealed that MK mRNA was also expressedin the normal breast tissues examined. Immunohistochemical analysisof the MK protein was performed on alimited number of the specimens, showing that somecancerous tissues were immunoreactive with anti-MK antibodies. Furthermore,using RT-PCR analysis, expression of not only thewild-type but also a truncated form of MK,which was recently found in various human tumorcell lines, was detected in 6 of 26cancerous tissues but not in non-cancerous tissues.

Expression of p21 (WAF1/CIP1) protein in clinical thyroid tissues

p21 (WAF1/CIP1) protein expression in various thyroid tissues, including thyroid carcinoma, was studied by means of immunohistochemistry using anti-p21 monoclonal antibody. Normal follicles and hyperplasias rarely expressed p21, whereas immunohistochemically positive cells were also too rarely found in follicular adenomas to justify these cases being classified as positive. Twenty eight of the 93 carcinomas examined (30.1%), however, were positive for p21. Of the p21-positive cases, 80% of the undifferentiated and 28.6% of the poorly differentiated carcinomas showed lesions co-expressing p21 and p53. If diffuse immunoreactivity of p53 reflects the p53 mutation, our results indicate that p21 in these carcinomas can be induced by p53-independent as well as by p53-dependent pathways. On the other hand, well-differentiated carcinomas did not co-express these two proteins and it therefore remains unclear whether p53-independent or p53-dependent pathways are predominant in this type of carcinoma. The incidence of expression of p21 was very similar in undifferentiated (26.3%), poorly (28.0%) and well-differentiated carcinomas (32.7%), even though they are characterised by different degree of malignancy. Furthermore, no correlation between p21 expression and either clinical parameters or patients prognosis could be established. These results suggest that p21 is only marginally related to the characteristics of thyroid carcinoma and can play only an adjuvant role in regulating the progression of this carcinoma.

The effect of local immunotherapy for breast cancer using a mixture of OK-432 and fibrinogen supplemented with activated macrophages

OK-432 is an immunomodulatory agent prepared from a strain ofStreptococcus pyogenes. We have previously reported that intratumoral injection of a mixture of OK-432 and fibrinogen (hereinafter referred to as OK/fbg) is very effective in the local immunotherapy for colorectal cancer. However, we found that the intratumoral injection of OK/fbg into tumor tissues of breast cancers did not always induce a strong antitumor effect. With conventional OK/fbg treatment, tumor necrosis observed in breast cancer tumors was significantly less than that in colorectal cancer tumors; the formation of fibrin meshwork and macrophage infiltration, in particular, were poor.In this study, the OK/fbg mixture was supplemented with activated macrophages for local immunotherapy of breast cancers. Macrophages were prepared from peripheral blood of breast cancer patients and activated with 0.05 mg/ml of OK-432. Between 2–7 days before operation, a single intratumoral injection of the above mixtures was done.The addition of activated macrophages to the OK/fbg mixture resulted in marked degrees of fibrin meshwork formation, macrophage infiltration and cancer cell necrosis.These findings suggest that the recruitment of macrophages in tumor stroma and their activation are necessary for sufficient induction of antitumor immunity, and supplementation of activated macrophages at the site of immune reaction may be an alternative method for reinforcement of the antitumor effect of local immunotherapy.

Expression of p16 and cyclin-dependent kinase 4 proteins in primary breast carcinomas

The immunolocalization of the p16 and cdk4 proteins was investigated in 65 retinoblastoma gene product (pRB)-positive and 20 pRB-negative breast carcinomas. These proteins were expressed in similar lesions in 84.6% of the pRB-positive and 100% of the pRB-negative carcinomas. Diffuse expression of p16 was observed in 73.8 and 70.0% of the pRB-positive and -negative cases, respectively. cdk4 and p16 expression was significantly more heterogeneous in tumors of larger sizes and/or at higher stages. These findings suggest that p16 can be induced regardless of pRB status and Rb gene function in primary breast carcinoma and that it modulates the cell cycle progression in association with cdk4.

Immunohistochemical study of cell cycle modulators in G1-S transition in clinical breast cancer tissue

In the present study, we investigated immunolocalization of the modulators of G1-S transition by using monoclonal or polyclonal antibodies for each of the modulators in 65 cases of clinical breast cancer. Two prominent cyclin dependent kinase (cdk)-cyclin complexes, cdk4-cyclin D and cdk2-cyclin E, were proved to have different modes of mutual expression. cdk4-positive lesions were found to equal cyclin D-expressing lesions in 55 cases, while the former were more extensive than the latter in 9 cases. On the other hand, cyclin E expression was detected in all the cases examined and was more dominant than that of cdk2/cdc2 in as many as 40 cases whereas the reverse was seen in only 1 case. Interestingly, cdk4 (p<0.01) and cyclin E (p<0.05) expressions showed an inverse relationship with the tumor size and the cancer stage. A similar tendency was also detected for two other positive modulators of G1-S transition, indicating that cell cycle progression must be regulated by the cancer itself once it has grown to a certain extent. p21, which has been regarded as a universal inhibitor of the cell cycle, was expressed in 43.1% of the cases examined and its immunoreactivity showed an inverse relationship with lymph node metastasis (p<0.05). It also tended to be absent more frequently in T3 or larger cancers and stage III cases. Moreover, two patients who died as a result of cancer and three patients with recurrence were all p21 negative, suggesting that p21 is prognosticably the most significant of all these modulators.

Clinicopathological findings and p53 expression of thyroid cancer in children

Although thyroid cancer tends to metastasize early in children, it is generally associated with a good prognosis. In this study, the expression of p53, mutations of which are found in many cancers, including anaplastic thyroid cancer, was examined to determine the relationship between cell proliferation and the clinical course of thyroid cancer. The clinicopathological findings and clinical courses of 15 children who underwent surgery before the age of 18 years at our hospital between 1972 and 1992 were examined, and the expression of p53 was studied using immunohistochemical techniques and an RNase protection assay. Postoperative follow-up ranged from 1 to 20 years, with a median of 12 years. No abnormal expression of p53 was detected in the thyroid cancer of any of the children tested, and none of them have died. The findings of this study therefore strongly suggest that p53 may play a role in the regulation of cell proliferation, and in this capacity slow the growth of and be related to the prognosis of differentiated thyroid cancer in children.