Understanding chemoresistance profiles of
brain tumors may aid in more educated selection of chemotherapeutic regimens for clinical trials and patient treatment. Although the literature contains many reports of the application of drug resistance assays, little is known about extreme drug resistance (EDR) in
primary brain tumors. We undertook this study to determine chemoresistance profiles for
brain tumors. From September 1991 to February 1998, we collected 64
brain tumor specimens from patients admitted to the Johns Hopkins Hospital.
Tumors were classified according to the revised World Health Organization system.
Brain tumor specimens were tested against 13 different chemotherapeutic agents using an extreme drug resistance assay. Results were reported as percent cell inhibition (PCI) (compared to control cultures). A drug resistance profile (extreme, intermediate, or low) was determined based on statistical comparison to a historical database of
tumor specimens tested against the same panel of chemotherapeutic agents.
Brain tumor specimens were classified histologically as
Grade IV astrocytoma (
glioblastoma multiforme, n = 35), Grade II/III
astrocytoma (n = 11),
oligodendroglioma (n = 6),
meningioma (n = 9),
hemangiopericytoma (n = 2), and
ependymoma (n = 1). A large percentage of
glioblastomas displayed extreme drug resistance to
paclitaxel (69%, n = 35), SN38 (75%, n = 28), and
vincristine (38%, n = 29). The majority of Grade II/III
astrocytomas displayed extreme drug resistance to
carboplatin (67%, n = 6),
cisplatin (60%, n = 10), and
paclitaxel (60%, n = 10). In a similar fashion,
oligodendrogliomas displayed extreme drug resistance to
vincristine (60%, n = 5) and
paclitaxel (50% n = 6). Most
meningiomas displayed extreme drug resistance to
vincristine (75%, n = 8),
dacarbazine (63%, n = 8), and 4-HC (50%, n = 8). Through the continued analysis of
brain tumor specimens and compilation of data from multiple institutions, chemoresistance profiles could assist in the development of rationale clinical trials and treatment regimens for patients with
brain tumors.