NOVEL ANTI-MALIGNANT TUMOR AGENT

The present invention provides an anti-tumor agent which is a molecular targeted drug for a malignant tumor and is highly safe. An anti-malignant tumor agent characterized by comprising, as an active ingredient, a substance capable of targeting a ribosome protein of which the expression is increased in a malignant tumor cell. The substance capable of targeting a ribosome protein of which the expression is increased in a malignant tumor cell according to the present invention is considered as a substance involved in a biological defense mechanism that is believed to be provided intrinsically in a living body and can prevent the development of diseases even if a cancer cell is generated. Specifically, the ribosome protein of which the expression is increased is RPL29 and/or RPS4X. A substance capable of targeting RPL29 and/or RPS4X is an anti-RPL29 antibody and/or an anti-RPS4X antibody, a substance capable of activating or enhancing an endogenous anti-RPL29 antibody and/or an endogenous anti-RPS4X antibody occurring in a living body, a substance capable of inducing the production of an anti-RPL29 antibody and/or an anti-RPS4X antibody in a living body, or an antagonist of RPL29 and/or RPS4X. The present invention also provides a method for testing an malignant tumor, in which an anti-RPL29 antibody titer and/or an anti-RPS4X antibody titer is employed as a measure.