MTUS2 and cholesteryl ester measurement: In the comparison of seven CE samples and 18 non-CE samples in the secretory phase, eight genes were upregulated in the CE group: two immunoglobulin genes (IGHG4 and JCHAIN) and six non-immunoglobulin genes (OVGP1, MTUS2, CLIC6, ACSM1, MESP1, and LTF) (Figure 6B).