TISSUE	FIX	BLOCK	SECTION	ANALYSIS
A. MAMMARY TISSUE
1. Mammary masses, including adjacent uninvolved mammary tissue where possible, or contralateral mammary gland*	x	X		Diagnosis and molecular analysis
2. Representative mammary glands**: Thoracic (#2/3 or #7/8) And Inguinal (#5 or #10)	x	X	Longitudinally ("fried egg morphology)	Preneoplastic changes
3. Remaining mammary glands	x			More extensive survey of preneoplastic changes, if required later
B. ORGANS TO ANALYZE FOR METASTASES
1. Lung	x	X		Metastases
2. Lymph nodes (axillary and inguinal)***	x	X		Metastases
3. Liver	x	X		Metastases
4. Femur (including marrow)	x		Longitudinal	Metastases
5. Vertebrae, with spinal cord	x		X-section cervical, thoracic, lumbar	Metastases
6. Brain	x		Half, sagittal	Metastases
C. OTHER HORMONALLY SENSITIVE ORGANS
1. Uterus, both ovaries	x	X		Changes in other hormonally sensitive organs
2. Pituitary	x	X		Pituitary changes that might affect MG
D. THE REST
1. Other gross lesions	x	X		Additional effects of experimental intervention
2. Rest of the mouse, including eg. head skin with ears	x			To allow other organs to be worked up later if necessary, and for confirmation of animal ID

* For masses >0.5cm diameter, snap freeze half for molecular analysis and fix remaining half. Separately freeze some uninvolved tissue (can use contralateral gland).**In all mice, including those without gross lesions, take at least two mammary glands routinely. Be consistent about always taking the same gland. If the chosen gland has a lesion, harvest the contralateral gland. (The adjacent thoracic glands 2/3 or 7/8 can be harvested together)

***The axillary and inguinal lymph nodes can each be sepapately grouped with other tissues when blocked, for ease of identification and to reduce the number of blocks.