A patient with ovarian cancer has elevated CA 15-3 but low CA-125 and CA-50 after chemotherapy. What is the most likely explanation?

The most likely explanation for elevated CA 15-3 levels in a patient with ovarian cancer who has low levels of CA-125 and CA-50 after chemotherapy involves the behavior and significance of these tumor markers in relation to the patient's condition. CA 15-3 is primarily associated with breast cancer, but it can be elevated in other malignancies, including ovarian cancer, particularly in cases of progression or recurrence.

In this scenario, the elevated CA 15-3 could indicate that the ovarian malignancy has recurred or that there is some degree of disease activity. On the other hand, low levels of CA-125 and CA-50 suggest that these specific markers for ovarian cancer are not indicating a recurrence or presence of residual disease at this time. Thus, it is reasonable to consider that while CA-125 and CA-50 are remaining low, the rise in CA 15-3 may reflect an ongoing pathological process, potentially due to metastatic activity or a more complex interaction of tumor biology.

The other options do not adequately explain the situation. Claiming that ovarian malignancy has recurred is the most straightforward interpretation given the context of the situation and the markers in question. It underscores the importance of understanding that while certain markers are more specific to particular