The Inhibin B test plays a key role in the diagnosis and monitoring of specific types of ovarian tumors. It is particularly useful in detecting granulosa cell tumors and mucinous epithelial ovarian tumors, which are known to overexpress inhibin B. Elevated levels of inhibin B in patients with these tumors can aid in both the initial diagnosis and the ongoing monitoring of tumor progression or recurrence, providing valuable insight into the management of these conditions.