Table 3. Univariate and multivariate analyses for clinical outcomes according to the classification based on the biomarker immunoprofiling in patients with salivary duct carcinoma.

		Overall survival						Progression-free survival
		Univariate analysis			Multivariate analysis			Univariate analysis			Multivariate analysis
	n (%)	HR	95% CI	P	HR	95% CI	P	HR	95% CI	P	HR	95% CI	P
Revised classification†
Apocrine A	36 (24)	1.00	–	–	1.00	–	–	1.00	–	–	1.00	–	–
Apocrine B	28 (18)	2.20	1.01–4.79	0.047*	1.75	0.78–3.92	0.178	2.49	1.33–4.68	0.004*	1.80	0.91–3.59	0.093
Apocrine HER2	53 (35)	1.87	0.93–3.78	0.080	2.19	0.97–4.95	0.058	1.92	1.09–3.39	0.025*	2.35	1.21–4.55	0.012*
HER2-enriched	17 (12)	2.60	1.14–5.91	0.023*	4.57	1.60–13.05	0.004*	2.19	1.05–4.55	0.037*	3.29	1.40–7.74	0.006*
Double negative	16 (11)	3.52	1.55–7.99	0.003*	2.36	0.94–5.90	0.067	4.80	2.42–9.49	<0.001*	3.01	1.36–6.65	0.006*
Di Palma classification‡
Luminal AR positive	64 (43)	1.00	–	–	1.00	–	–	1.00	–	–	1.00	–	–
HER2 positive	70 (47)	1.45	0.87–2.42	0.156	1.83	0.97–3.45	0.061	1.32	0.87–2.01	0.194	1.82	1.11–3.00	0.019*
Basal-like	11 (7)	2.69	1.16–6.21	0.021*	1.53	0.60–3.87	0.374	3.76	1.91–7.38	<0.001*	2.63	1.22–5.68	0.014*
Intermediate	5 (3)	2.18	0.76–6.28	0.149	1.92	0.63–5.83	0.251	2.37	0.93–6.02	0.069	1.43	0.51–4.02	0.493

* Statistically significant (P < 0.05)

†Apocrine A, AR+/HER2−/Ki-67-low; Apocrine B, AR+/HER2−/Ki-67-high; Apocrine HER2, AR+/HER2+; HER2-enriched, AR−/HER2+; Double negative, AR−/HER2− (including basal-like [AR−/HER2−/EGFR and/or CK5/6+] and unclassified [others]).

‡Luminal AR positive, AR+/HER2−; HER2 positive, AR any/HER2+; Basal-like, AR−/HER2−/EGFR and/or CK5/6+; Intermediate, negative for all markers.

Abbreviations: HR = hazard ratio; CI = confidence interval; HER2 = human epidermal growth factor receptor 2; AR = androgen receptor; EGFR = epidermal growth factor receptor; CK = cytokeratin.