Prophylactic or therapeutic against exacerbation or recurrence of cancer, and screening method therefor

A method for screening a prophylactic or therapeutic agent against relapse or recurrence of cancer due to cells including dormant cancer stem cells in cancer tissue during chemotherapy, the method comprising:

• (a) allowing a chemotherapeutic agent to act on cancer organoids, resulting in death of most cells of the cancer organoids;
• (b) further incubating the cancer organoids, resulting in start of proliferation of cells including dormant cancer stem cells present in the cancer organoids;
• and
• (c) evaluating the proliferation of the cells including the dormant cancer stem cells,
• wherein the (a) or (b) is carried out in the presence of a test substance, and the fact that the proliferation of the cells including the dormant cancer stem cells is inhibited compared to that in the absence of the test substance indicates that the test substance is a prophylactic or therapeutic agent against relapse or recurrence of cancer due to cells including dormant cancer stem cells in cancer tissue during chemotherapy.

A method for screening a prophylactic or therapeutic agent against relapse or recurrence of cancer due to cells including dormant cancer stem cells in cancer tissue during chemotherapy, the method comprising:

• (a) allowing a chemotherapeutic agent to act on cancer organoids, resulting in death of most cells of the cancer organoids;
• (b) further incubating the cancer organoids, resulting in start of proliferation of cells including dormant cancer stem cells present in the cancer organoids;
• and
• (c) evaluating activation of YAP signaling in the cells including the dormant cancer stem cells,
• wherein the (a) or (b) is carried out in the presence of a test substance, and the fact that the activation of YAP signaling is inhibited compared to that in the absence of the test substance indicates that the test substance is a prophylactic or therapeutic agent against relapse or recurrence of cancer due to cells including dormant cancer stem cells in cancer tissue during chemotherapy.

A method for screening a prophylactic or therapeutic agent against relapse or recurrence of cancer due to cells including dormant cancer stem cells in cancer tissue during chemotherapy, the method comprising:

• incubating LGR5-positive p27-positive cancer stem cells dissociated into single cells in the presence of a test substance;
• and
• evaluating the proliferation of the LGR5-positive p27-positive cancer stem cells,
• wherein the fact that the proliferation of the LGR5-positive p27-positive cancer stem cells is inhibited compared to that in the absence of the test substance indicates that the test substance is a prophylactic or therapeutic agent against relapse or recurrence of cancer due to cells including dormant cancer stem cells in cancer tissue during chemotherapy.

A method for screening a prophylactic or therapeutic agent against relapse or recurrence of cancer due to cells including dormant cancer stem cells in cancer tissue during chemotherapy, the method comprising:

• incubating LGR5-positive p27-positive cancer stem cells dissociated into single cells in the presence of a test substance;
• and
• evaluating activation of YAP signaling in the LGR5-positive p27-positive cancer stem cells,
• wherein the fact that the activation of YAP signaling is inhibited compared to that in the absence of the test substance indicates that the test substance is a prophylactic or therapeutic agent against relapse or recurrence of cancer due to cells including dormant cancer stem cells in cancer tissue during chemotherapy.

A method for screening a prophylactic or therapeutic agent against relapse or recurrence of cancer due to cells including dormant cancer stem cells in cancer tissue during chemotherapy, the method comprising:

• incubating LGR5-positive p27-positive cancer stem cells dissociated into single cells in the presence of a test substance;
• and
• evaluating expression of COL17A1 in the LGR5-positive p27-positive cancer stem cells,
• wherein the fact that the expression of COL17A1 is elevated compared to that in the absence of the test substance indicates that the test substance is a prophylactic or therapeutic agent against relapse or recurrence of cancer due to cells including dormant cancer stem cells in cancer tissue during chemotherapy.

A method for screening a prophylactic or therapeutic agent against relapse or recurrence of cancer due to cells including dormant cancer stem cells in cancer tissue during chemotherapy, the method comprising:

• allowing a chemotherapeutic agent to act on cancer organoids in the presence of a test substance;
• and
• evaluating expression of COL17A1 in the cancer organoids,
• wherein the fact that the expression of COL17A1 is elevated compared to that in the absence of the test substance indicates that the test substance is a prophylactic or therapeutic agent against relapse or recurrence of cancer due to cells including dormant cancer stem cells in cancer tissue during chemotherapy.