An isolated nucleic acid encoding a C-terminal fragment of paraspeckle component 1 （PSPC1） is disclosed. The C-terminal fragment of the PSPC1 comprises an extension of more than 10 but no greater than 131 amino acid residues with its C-terminal amino acid identical to the C-terminus of the PSPC1 sequence SEQ ID NO: 3 and exhibits a biological activity against tumor cells. The tumor cells are associated with either PSPC1 or protein tyrosine kinase 6 （PTK6）, or both. The anti-tumor activity is at least one selected from the group consisting of: （a） suppressing tumor cell growth； （b） suppressing tumor cell progression； （c） suppressing tumor cell metastasis； （d） decreasing PSPC1 expression； and （e） decreasing oncogenic PTK6 expression in cytoplasm. Also disclosed is a peptide comprising a C-terminal fragment sequence of PSPC1. A reagent kit and method for predicting tumor progression, metastasis, and prognosis in a cancer patient are also disclosed.本發明揭示一種經分離之核酸，其編碼轉移的旁斑成分1（PSPC1）的C端片段。PSPC1的C端片段包含一大於10個但不超過131個胺基酸殘基的延伸，其中其C端胺基酸等同於PSPCl序列SEQ ID NO: 3的C端，且呈現對抗腫瘤細胞之生物活性。腫瘤細胞結合於PSPC1或蛋白質酪胺酸激酶6（PTK6）、或兩者。抗腫瘤活性係至少一選自於由：（a）抑制腫瘤細胞生長；（b）抑制腫瘤細胞進程；（c）抑制腫瘤細胞轉移；（d）減少PSPC1表達；以及（e）減少細胞質中致癌性PTK6的表達所組成群組。本發明亦揭示一種包含PSPC1之C端片段序列的胜肽。本發明亦揭示用於預測癌症病患之腫瘤進展、轉移、及預後的試劑套組及方法。
