Molecular tumor profiling (MTP) is a potentially powerful diagnostic tool for identifying the tissue of origin in patients with cancer of unknown primary (CUP). However, validation of the accuracy and clinical value of MTP has been difficult because the anatomic primary site in most patients is never identified. From March 2008 through January 2010, clinicopathologic data from 171 CUP patients who had MTP (CancerTYPE ID; bioTheranostics, Inc, San Diego, CA) performed on archived material were evaluated. The accuracy of MTP diagnoses was evaluated by comparison with 1) latent primary tumor sites found months/years later; 2) initial single diagnoses by immunohistochemistry (IHC); and 3) additional directed IHC and/or clinicopathologic findings evaluated after MTP diagnoses. A single MTP diagnosis was made in 144 of 149 patients with adequate tumor specimens. Eighteen of 24 patients with latent primaries discovered months to years later had correct diagnoses by MTP (75%), and these diagnoses compared favorably with IHC. Single IHC diagnoses matched MTP diagnoses in 40 of 52 patients (77%). IHC predictions of 2 or more possible primaries compared poorly with MTP diagnoses. However, additional targeted IHC and clinical/histologic evaluation supported the MTP diagnosis in 26 of 35 patients (74%). Clinical features were usually consistent with MTP diagnoses (70%). The diagnostic accuracy of this MTP assay was supported by a high level of agreement with identified latent primaries (75%), single IHC diagnoses (77%), and additional directed IHC and/or clinical/histologic findings (74%) prompted by the MTP diagnoses. MTP complements standard pathologic evaluation in determining the tissue of origin in patients with CUP, particularly when IHC is inconclusive.

Introduction.: This retrospective, multi-institutional study evaluated the accuracy of tissue-of-origin prediction by molecular profiling in patients with carcinoma of unknown primary site (CUP). Methods.: Thirty-eight of 501 patients (7.6%) with CUP, seen in 2000–2008, had their latent primary site tumor subsequently identified during life. Twenty-eight of these patients (73.7%) had adequate initial tissue biopsies available for molecular profiling with a reverse transcriptase-polymerase chain reaction (RT-PCR) assay (Cancer Type ID; bioTheranostics, Inc., San Diego, CA). The assay was performed on formalin-fixed paraffin-embedded biopsy specimens in a blinded fashion, and the assay results were compared with clinicopathologic data and the actual latent primary sites. Results.: Twenty of the 28 (71.4%) RT-PCR assays were successfully completed (eight biopsies had either insufficient tumor or poorly preserved RNA). Fifteen of the 20 assay predictions (75%) were correct (95% confidence interval, 60%–85%), corresponding to the actual latent primary sites identified after the initial diagnosis of CUP. Primary sites correctly identified included breast (four patients), ovary/primary peritoneal (four patients), non-small cell lung (three patients), colorectal (two patients), gastric (one patient), and melanoma (one patient). Three predictions were incorrect (intestinal, testicular, sarcoma) in patients with gastroesophageal, pancreatic, and non-small cell lung cancer, respectively, and two were unclassifiable in patients with non-small cell lung cancer. Clinicopathologic findings were helpful in suggesting the correct primary site in some patients and appear to complement the molecular assay findings. Conclusions.: These data validate the reliability of this assay in predicting the primary site in CUP patients and may form the basis for more successful site-directed therapy, when used in concert with clinicopathologic data.

Purpose: This study was conducted to assess the safety, tolerability, pharmacokinetics, and pharmacodynamics of the i.v. pan-aurora kinase inhibitor PHA-739358, danusertib, in patients with advanced solid tumors. Experimental Design: In part 1, patients received escalating doses of danusertib (24-hour infusion every 14 days) without filgrastim (granulocyte colony-stimulating factor, G-CSF). Febrile neutropenia was the dose-limiting toxicity without G-CSF. Further dose escalation was done in part 2 with G-CSF. Blood samples were collected for danusertib pharmacokinetics and pharmacodynamics. Skin biopsies were collected to assess histone H3 phosphorylation (pH3). Results: Fifty-six patients were treated, 40 in part 1 and 16 in part 2. Febrile neutropenia was the dose-limiting toxicity in part 1 without G-CSF. Most other adverse events were grade 1 to 2, occurring at doses ≥360 mg/m² with similar incidence in parts 1 and 2. The maximum tolerated dose without G-CSF is 500 mg/m². The recommended phase 2 dose in part 2 with G-CSF is 750 mg/m². Danusertib showed dose-proportional pharmacokinetics in parts 1 and 2 with a median half-life of 18 to 26 hours. pH3 modulation in skin biopsies was observed at ≥500 mg/m². One patient with refractory small cell lung cancer (1,000 mg/m² with G-CSF) had an objective response lasting 23 weeks. One patient with refractory ovarian cancer had 27% tumor regression and 30% CA125 decline. Conclusions: Danusertib was well tolerated with target inhibition in skin at ≥500 mg/m². Preliminary evidence of antitumor activity, including a partial response and several occurrences of prolonged stable disease, was seen across a variety of advanced refractory cancers. Phase II studies are ongoing. (Clin Cancer Res 2009;15(21):6694–701)

This paper explores the enigma of cancer of unknown primary (CUP) in relation to rapidly improving molecular diagnostic approaches. It is based on the first global collaboration meeting on improving research and clinical outcomes in CUP organized by the CUP Foundation. We review the difficulties of classifying this widely heterogeneous disease and the available diagnostic and pathological evaluative techniques, focusing on molecular profiling. Retrospective studies in CUP patients are shown to provide indirect validation of the accuracy of several platforms of gene expression profiling assays that may identify CUP subsets that respond favorably to active chemotherapy regimens. This review concludes that the recent major improvements in pathologic and molecular diagnostics, coupled with new improved therapies for several specific advanced solid tumors, need to be harmonized with more evidence from clinical–translational trials. All patients with CUP could thus be appropriately managed without the constant uncertainty that has previously severely hampered patient care and optimal outcomes. The longer-term objective is to understand the biology of highly metastatic disease, leading to the development of future global therapeutic programs. Current clinical studies, such as CUP-ONE, will address some of these issues.