Glypican epitopes and uses thereof

An isolated epitope or epitope segment for an anti-glypican 1 (GPC-1) antibody located within a portion of the GPC-1 flexible loop defined by an amino acid sequence KVNPQGPGPEEK (SEQ ID NO:

• 1), wherein the isolated epitope or epitope segment consists of:
• (i) KVNPQGPGPEEK (SEQ ID NO:
• 1);
• (ii) a fragment of KVNPQGPGPEEK (SEQ ID NO:
• 1) consisting of VNPQGPGPEEK (SEQ ID NO:
• 2), VNPQGPGPEE (SEQ ID NO:
• 3), NPQGPGPEE (SEQ ID NO:
• 4), KVNPQGPGPE (SEQ ID NO:
• 5) or KVNPQGPGP (SEQ ID NO:
• 6);
• (iii) a variant of SEQ ID NO:
• 3 with a substitution at any one or more of:
• position 1, wherein V (val) is substituted with any other amino acid,
• position 2, wherein N (asn) is substituted with any other amino acid,
• position 3, wherein P (pro) is substituted with any other amino acid,
• position 4, wherein Q (gln) is substituted with any one of Y (tyr), A (ala), E (glu), V (val), M (met), F (phe), L (leu), I (ile), T (thr), or R (arg), position 5, wherein G (gly) is substituted with A (ala), S (ser), T (thr), H (his), W (trp), Y (tyr), F (phe), or M (met),
• position 8, wherein P (pro) is substituted with any other amino acid,
• position 10, wherein E (glu) is substituted with Q (gln), D (asp), F (phe), H (his) or M (met),
• (iv) a variant of SEQ ID NO:
• 4 with a substitution at any one or more of:
• position 1, wherein N (asn) is substituted with H (his),
• position 2, wherein P (pro) is substituted with any other amino acid,
• position 3, wherein Q (gln) is substituted with any one of N (asn), M (met), T (thr), S (ser), or R (arg),
• position 5, wherein P (pro) is substituted with A (ala),
• position 7, wherein P (pro) is substituted with any one of A (ala), D (asp), C (cys), E (glu), Z (glx), G (gly), H (his), K (lys), M (met), F (phe), P (pro), S (ser), T (thr), W (trp), or Y (tyr),
• position 9, wherein E (glu) is substituted with any other amino acid;
• or
• (v) a variant of SEQ ID NO:
• 5 or SEQ ID NO:
• 6 with a substitution only at any one or more of:
• position 1, wherein K (lys) is substituted with any one of W (trp), R (arg), L (lys), Y (tyr) or F (phe);
• position 3, wherein N (asn) is substituted with any one of H (his), P (pro) or D (asp);
• position 4, wherein P (pro) is substituted with any one of R (arg), K (lys), W (trp), S (ser), H (his) or N (asn);
• position 8, wherein G (gly) is substituted with any one of D (asp), E (glu), N (asn), Q (gln), K (lys), R (arg) or A (ala);
• position 9, wherein P (pro) is substituted with any one of M (met), A (ala), I (ile), K (lys), R (arg), Q (gln), S (ser), T (thr), or Y (tyr).