Table 1.

Characteristics of 97 patients with carcinoma of unknown primary. cfDNA, cell‐free DNA; IHC, immunohistochemistry; MSI, microsatellite instability; NGS, next‐generation sequencing; TMB, tumour mutation burden. See Fig. S2 that describes overlap of test types.

Basic characteristics
Age at diagnosis, median (range), year	63 (21–95)
Woman, number (%)	59 (60.8%)
Histology, number (%)
Adenocarcinoma	52 (54%)
Neuroendocrine carcinoma	18 (19%)
Squamous cell carcinoma	10 (10%)
Poorly differentiated a	14 (14%)
Other b	3 (3%)
Molecular profiling
Number of patients who had tissue NGS, number (%)	74 (76%)
Median number of characterized alterations from tissue NGS (range)	4 (0–25)
Number of patients who had cfDNA, number (%)	72 (74%)
Median number of characterized alterations from cfDNA (range)	2 (0–9)
Immune profiling
Number of patients who had MSI testing	55 (N = 52 from tissue, N = 3 from cell‐free DNA)
Patients with MSI‐high/defect in a mismatch repair gene (%)	2/55 (3.6%)
Number of patients who had tissue‐based TMB testing	64
TMB‐Low (≤ 5 mutations·Mb−1) c	40/64 (62.5%)
TMB‐intermediate (6–19 mutations·Mb−1) c	18/64 (28.1%)
TMB‐high (≥ 20 mutations·Mb−1) c	6/64 (9.4%)
Patients with TMB ≥ 10 mutations·Mb−1	15/64 (23%)
Patients with NTRK fusion‐positive	None
Number of patients who had PD‐L1 testing by IHC	55
PD‐L1 positive d	17/55 (30.9%)
Number of patients who had comprehensive immune profiling by RNA sequencing	12

^a Not defined as adenocarcinoma, squamous cell carcinoma or neuroendocrine histology.

^b Sarcomatoid carcinoma, carcinoma (favoured but not limited to cholangiocarcinoma, hepatocellular carcinoma or breast primary), malignant epithelial neoplasm most consistent with gastrointestinal tract or biliary primary (N = 1 each).

^c Or as defined by the vendor/laboratory.

^d Defined as ≥ 1% by IHC from tumour (N = 16) or from tumour‐infiltrating lymphocyte (N = 1).