Gene-specific methylation status
		All breast cancer cases			Methylated breast tumor			Unmethylated breast tumor
Genes	Body mass index	ER+PR+/ all others	OR	(95% CI)	ER+PR+/ all others	OR	(95% CI)	ER+PR+/ all others	OR	(95% CI)	p for interaction
APC
	BMI(<25kg/m^2)	79/80	1.00	reference	41/39	1.00	reference	38/41	1.00	reference	0.266
	BMI (25-29.9kg/m^2)	77/50	1.55	(0.96, 2.49)	35/27	1.24	(0.64, 2.43)	42/23	1.89	(0.95, 3.75)
	BMI (≥30kg/m^2)	73/39	1.89	(1.15, 3.12)	35/22	1.51	(0.76, 3.02)	38/17	2.39	(1.16, 4.92)
BRCA1
	BMI (<25kg/m^2)	87/82	1.00	reference	51/45	1.00	reference	36/37	1.00	reference	0.300
	BMI (25-29.9kg/m^2)	82/56	1.36	(0.86, 2.10)	46/36	1.12	(0.62, 2.03)	36/20	1.84	(0.89, 3.80)
	BMI (≥30kg/m^2)	78/41	1.79	(1.10, 2.91)	44/23	1.70	(0.89, 3.24)	34/18	1.93	(0.93, 4.04)
CDH1
	BMI (<25kg/m^2)	78/80	1.00	reference	6/7	1.00	reference	72/73	1.00	reference	--
	BMI (25-29.9kg/m^2)	70/48	1.48	(0.91, 2.41)	3/5	not estimated		67/43	1.57	(0.95, 2.60)
	BMI (≥30kg/m^2)	76/38	2.05	(1.25, 3.38)	4/2	not estimated		72/36	2.03	(1.21, 3.40)
CYCLIND2
	BMI (<25kg/m^2)	78/80	1.00	reference	15/17	1.00	reference	63/63	1.00	reference	0.763
	BMI (25-29.9kg/m^2)	70/48	1.48	(0.91, 2.41)	18/14	1.46	(0.54, 3.93)	52/34	1.51	(0.86, 2.64)
	BMI (≥30kg/m^2)	76/38	2.05	(1.25, 3.38)	18/9	2.26	(0.78, 6.56)	58/29	2.00	(1.13, 3.52)
DAPK
	BMI (<25kg/m^2)	78/80	1.00	reference	11/10	1.00	reference	67/70	1.00	reference	0.290
	BMI (25-29.9kg/m^2)	70/48	1.48	(0.91, 2.41)	10/9	1.02	(0.29, 3.62)	60/39	1.59	(0.94, 2.69)
	BMI (≥30kg/m^2)	76/38	2.05	(1.25, 3.38)	17/6	2.59	(0.73, 9.18)	59/32	1.93	(1.12, 3.34)
ESR1
	BMI (<25kg/m^2)	86/82	1.00	reference	40/36	1.00	reference	46/46	1.00	reference	0.004
	BMI (25-29.9kg/m^2)	82/55	1.41	(0.89, 2.22)	39/15	2.33	(1.11, 4.93)	43/40	1.05	(0.58, 1.92)
	BMI (≥30kg/m^2)	78/41	1.81	(1.12, 2.94)	33/24	1.24	(0.62, 2.48)	45/17	2.63	(1.32, 5.25)
GSTP1
	BMI (<25kg/m^2)	78/80	1.00	reference	18/16	1.00	reference	60/64	1.00	reference	0.224
	BMI (25-29.9kg/m^2)	70/48	1.48	(0.91, 2.41)	19/16	1.04	(0.40, 2.68)	51/32	1.69	(0.96, 2.98)
	BMI (≥30kg/m^2)	76/38	2.05	(1.25, 3.38)	20/14	1.28	(0.49, 3.33)	56/24	2.49	(1.38, 4.51)
HIN
	BMI (<25kg/m^2)	78/80	1.00	reference	46/33	1.00	reference	32/47	1.00	reference	0.130
	BMI (25-29.9kg/m^2)	70/48	1.48	(0.91, 2.41)	48/32	1.07	(0.56, 2.02)	22/16	2.00	(0.91, 4.40)
	BMI (≥30kg/m^2)	76/38	2.05	(1.25, 3.38)	54/19	2.03	(1.02, 4.05)	22/19	1.72	(0.80, 3.70)
p16
	BMI (<25kg/m^2)	75/80	1.00	reference	1/3	not estimated		74/77	1.00	reference	--
	BMI (25-29.9kg/m^2)	75/50	1.59	(0.98, 2.57)	2/3	not estimated		73/47	1.61	(0.98, 2.63)
	BMI (≥30kg/m^2)	71/39	1.94	(1.17, 3.20)	3/2	not estimated		68/37	1.91	(1.15, 3.19)
PR
	BMI (<25kg/m^2)	87/82	1.00	reference	9/18	1.00	reference	78/64	1.00	reference	--
	BMI (25-29.9kg/m^2)	82/56	1.36	(0.86, 2.16)	6/7	1.71	(0.44, 6.61)	76/49	1.25	(0.76, 2.04)
	BMI (≥30kg/m^2)	78/41	1.79	(1.10, 2.91)	8/1	not estimated		70/40	1.43	(0.86, 2.38)
RARB
	BMI (<25kg/m^2)	78/80	1.00	reference	18/27	1.00	reference	60/53	1.00	reference	0.598
	BMI (25-29.9kg/m^2)	70/48	1.48	(0.91, 2.41)	17/19	1.30	(0.53, 3.18)	53/29	1.60	(0.89, 2.88)
	BMI (≥30kg/m^2)	76/38	2.05	(1.25, 3.38)	18/12	2.25	(0.87, 5.78)	58/26	1.97	(1.09, 3.57)
RASSF1A
	BMI (<25kg/m^2)	78/80	1.00	reference	64/67	1.00	reference	14/13	1.00	reference	--
	BMI (25-29.9kg/m^2)	70/48	1.48	(0.91, 2.41)	61/43	1.50	(0.89, 2.52)	9/5	not estimated
	BMI (≥30kg/m^2)	76/38	2.05	(1.25, 3.38)	67/26	2.69	(1.53, 4.75)	9/12	0.67	(0.21, 2.15)
TWIST
	BMI (<25kg/m^2)	78/80	1.00	reference	9/17	1.00	reference	69/63	1.00	reference	0.317
	BMI (25-29.9kg/m^2)	70/48	1.48	(0.91, 2.41)	12/10	2.44	(0.73, 8.13)	58/38	1.38	(0.81, 2.35)
	BMI (≥30kg/m^2)	76/38	2.05	(1.25, 3.38)	13/7	3.51	(1.03, 11.96)	63/31	1.86	(1.07, 3.22)

Table 3: Age-adjusted odds ratios (ORs) and 95% CIs (CIs) for the association between postmenopausal body mass index (BMI) and ER+PR+ breast cancer (vs. all others cases: ER-, PR-, ER+PR-, ER-PR+) considering gene-specific methylation status of the tumor (methylated vs. unmethylated), the Long Island Breast Cancer Study Project (1996-1997).