Activation of EDTA-resistant gelatinases in malignant human tumors

Among the many proteases associated with human cancer, seprase or fibroblast activation protein alpha, a type II transmembrane glycoprotein, has two types of EDTA-resistant protease activities: dipeptidyl peptidase and a 170-kDa gelatinase activity. To test if activation of gelatinases associated with seprase could be involved in malignant tumors, we used a mammalian expression system to generate a soluble recombinant seprase (r-seprase). In the presence of putative EDTA-sensitive activators, r-seprase was converted into 70- to 50-kDa shortened forms of seprase (s-seprase), which exhibited a 7-fold increase in gelatinase activity, whereas levels of dipeptidyl peptidase activity remained unchanged. In malignant human tumors, seprase is expressed predominantly in tumor cells as shown by in situ hybridization and immunohistochemistry. Proteins purified from experimental xenografts and malignant tumors using antibody- or lectin-affinity columns in the presence of 5 mmol/L EDTA were assayed for seprase activation in vivo. Seprase expression and activation occur most prevalently in ovarian carcinoma but were also detected in four other malignant tumor types, including adenocarcinoma of the colon and stomach, invasive ductal carcinoma of the breast, and malignant melanoma. Together, these data show that, in malignant tumors, seprase is proteolytically activated to confer its substrate specificity in collagen proteolysis and tumor invasion

Successful osimertinib rechallenge after osimertinib-induced pneumonitis in a patient with lung adenocarcinoma

Pneumonitis is a serious adverse event of EGFR-TKI treatment. Although several cases of EGFR-TKI rechallenge after EGFR-TKI-induced pneumonitis have been reported, little is known about post-pneumonitis osimertinib rechallenge. We describe a 69-year-old never-smoking Japanese woman with postoperative recurrent lung adenocarcinoma retreated with osimertinib after osimertinib-induced pneumonitis. Although osimertinib rechallenge must be carefully chosen based on risk/benefit analysis, osimertinib rechallenge after osimertinib-induced pneumonitis may be an option, with limited alternative therapeutic options. Keywords: Osimertinib, Pneumonitis, Rechallenge, Corticosteroi

Successful retreatment with osimertinib after osimertinib-induced acute pulmonary embolism in a patient with lung adenocarcinoma: A case report

AbstractPulmonary embolism (PE) can be life-threatening, and it is challenging to diagnose because of its nonspecific signs and symptoms. PE is also an important potential risk of osimertinib treatment, however, clinical courses regarding retreatment after osimertinib-induced acute pulmonary embolism remain unclear. We described a 77-year-old woman with postoperative recurrent lung adenocarcinoma who developed osimertinib-induced acute PE. She received apixaban and was later successfully retreated with osimertinib. This case suggests that retreatment with osimertinib after osimertinib-induced acute PE may be a treatment option when alternative therapeutic options are limited

Transformation to small cell lung cancer after first-line afatinib treatment

Acquiring resistance to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) is inevitable. Transformation to small cell lung cancer (SCLC) is reported as a possible mechanism of this acquired resistance. We describe the case of a 35-year-old man with lung adenocarcinoma harboring EGFR exon 19 deletion. After 7 months of successful treatment with afatinib, he experienced relapse and rebiopsy revealed SCLC with EGFR exon 19 deletion. Tumor marker tests at this point showed normal levels of serum neuron-specific enolase and pro-gastrin releasing peptide. Our case highlights the importance of rebiopsy for revealing SCLC transformation, a potential mechanism of acquired resistance to afatinib as with other EGFR-TKIs, and normal-range values of tumor markers for SCLC cannot exclude the possibility of SCLC transformation. Keywords: Transformation, Small cell lung cancer, Adenocarcinoma, Rebiopsy, Acquired resistance, Afatini