Midkine expression in human breast cancers: Expression of truncated form

Abstract

The expression of midkine (MK), a growth/differentiation factor, was assessed in 34 surgically resected specimens of primary breast cancer or mastopathy. Using reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, all of the non-cancerous and cancerous tissues were found to express MK except for one breast cancer specimen. Northern blot analysis revealed that MK mRNA was also expressed in the normal breast tissues examined. Immunohistochemical analysis of the MK protein was performed on a limited number of the specimens, showing that some cancerous tissues were immunoreactive with anti-MK antibodies. Furthermore, using RT-PCR analysis, expression of not only the wild-type but also a truncated form of MK, which was recently found in various human tumor cell lines, was detected in 6 of 26 cancerous tissues but not in non-cancerous tissues.

Truncated midkine as a marker of diagnosis and detection of nodal metastases in gastrointestinal carcinomas

“…In all of ten patients with nodal involvement, both primary tumour and metastatic lymph node expressed truncated MK. On the other hand, in three samples from hepatic metastatic sites (cases 2, 40 and 47), full-size MK was expressed but the truncated type was not (Figure 4) Miyashiro et al, 1996Miyashiro et al, , 1997. These results are British Joumal of Cancer (1998) 78(4), 472-477…”

“…A truncated form of MK mRNA, which encodes MK devoid of the N-terminally located domain, was found in Wilms' tumour, pancreatic carcinoma, gastric carcinoma, colon carcinoma and breast carcinoma but not in adjacent normal tissue Miyashiro et al, 1996Miyashiro et al, , 1997. The truncated MK is essentially composed of functionally important C-terminally located domain (Muramatsu et al, 1994;Kojima et al, 1995c), and is shortlived because of the lack of N-terminally located domain, which protects the C-terminally located domain from protease attack (Matsuda et al, 1996).…”

Pleiotrophin, A Multifunctional Tumor Promoter Through Induction of Tumor Angiogenesis, Remodeling of the Tumor Microenvironment, and Activation of Stromal Fibroblasts

“…As cited above, both Ptn (and Mk) are expressed in many breast cancers and in cell lines derived from breast cancers. 14,51,[55][56][57][72][73][74][75][76][77][78][79] Targeting PTN has reversed the malignant phenotype of human breast cancer cells. 51 Recently, PTN expression was demonstrated in human breast cancers using immunohistochemistry coupled with enhancers of the signal generated by horseradish peroxidase.…”

Promotion of self-renewal of embryonic stem cells by midkine

“…It is highly expressed during midgestation and down-regulated at birth [5] . MK is expressed in multiple types of tumors and functions to promote their proliferation and metastasis [6][7][8][9][10][11] . As many cancer-related molecules play significant roles in ESCs and EC cells are considered transformed ESCs, we set out to characterize the expression and function of MK in an in vitro ESC culture system.…”