PhD defence L. (Lucia) Suzuki

The number of new patients with an adenocarcinoma of the esophagus (EAC) and its precursor lesion, Barrett's esophagus, is increasing rapidly. Endoscopic treatment is still possible at an early stage, but a more advanced stage requires highly invasive treatment. In this thesis, several biomarkers are evaluated, so that in the future the most optimal treatment strategy can be chosen for each patient.
It appears that the presence of many tumor buds, scored according to the Ohike method and a low OLFM4 expression, in patients with so-called early carcinomas (pT1b EAC), are independent risk factors for metastases. In advanced EAC patients treated with surgery alone, an abnormal immunohistochemical staining pattern of p53 appears to be an independent risk factor for poor prognosis. In addition, the staining pattern correlates well with the mutation status of the TP53 gene. Currently, however, most patients with advanced EAC are pretreated with chemoradiation (nCRT) prior to removal of the esophagus. To date, the effect of this on the expression of biomarkers and their prognostic value is unknown. This thesis describes that aberrant p53 and SOX2 expression remains largely the same after nCRT. This thesis emphasizes that the analysis of only a single biomarker is unlikely to predict the progression, presence of metastases or recurrence risk in an individual patient. It is much more likely that a combination of multiple risk factors, or biomarkers, will provide a better estimate. This thesis describes some (additional) promising markers that can be used for this purpose.

The PhD defences do not take place publicly in the usual way in the Senate Hall at campus Woudestein or in the Professor Andries Querido Room at the Erasmus MC. The candidates will defend their dissertation either in a small group or online.